LHC - the last chance for all theories of everything? [Archive]

tom.stoer

Aug22-09, 05:46 AM

I think the things that the LHC should be able to prove or disprove, at least to some degree, is the Higgs boson and supersymmetry. And even if in these cases there may well be ways out if they don't find them at the energy levels of the LHC (theorists who love SUSY will just claim its at a higher energy scale). All we can really do is hope that they find something significant so that governments continue to fund fundamental physics experiments otherwise we may enter an age where there is relatively little empirical evidence to guide new theories.

That's the very core of the discussion. The LHC can find evidence for entities like Higgs, SUSY, etc. iff they are in the LHC's energy range.

For the SM Higgs it's pretty clear: if the LHC does not prove its existence it automatically disproves the SM. For all other topics it can only push the limits of their "existence" to higher energies.

So that automatically means the LHC will be absolutely mute about any "ToE". It can support theories with respect to their low energy regime, but nothing else.

For example string theory (with small extra dimensions): as its low energy limit is a certain SUGRA, the LHC cannot distinguish between the two scenarios "ST is the ToE" and "SUGRA is the ToE".

My conclusion is that something like a ToE cannot exist in a physical sense:
a) you can only "prove", support or disprove a theory in a very restricted sense = in certain regimes
b) a ToE should be able to tell you why it is the ToE; I don't think that ST does only because it is allowed to exist in a 10-D spacetime: it does not tell you why other approaches must fail
c) in a certain sense the discussions regarding duality show that there may be not one fundamental theory but only certain dual descriptions of something we like to call "reality" - whatever that means;
look at QFT: what are the fundamental entities of a "quantum ontology"? state vectors in Fock space and field operators - or path integrals and "trajectories in field configuration space";
look at ST: there are dualities between very different string theories, compactifications etc.
so in terms of ontology this question is undecidable;
d) any mathematical approach to a ToE is not able to prove why this approach must be mathematical at all

marcus

Aug22-09, 07:00 AM

Tom
How does your perspective compare with the one Weinberg presented towards the end of his 6 July Cern talk?

I expect you may have watched it but in case not I'll get the link.
http://cdsweb.cern.ch/record/1188567/

I mentioned in this 11 July post
http://physicsforums.com/showthread.php?p=2268482#post2268482
that to save time you can drag the time button to minute 58 (if you want to skip the historical part) and get to the core message
which is in the last 12 minutes.

The slides are here:
http://itpworkshop.unibe.ch/MaKaC/getFile.py/access?contribId=126&sessionId=19&resId=0&material Id=slides&confId=2

There was further discussion here:
http://physicsforums.com/showthread.php?t=324841

The title of the Cern talk was "The Quantum Theory of Fields--Effective or Fundamental?"

tom.stoer

Aug24-09, 03:55 PM

Marcus, which statement or perspective do you mean?

The first one regarding the LHC energy range?
The LHC can find evidence for entities like Higgs, SUSY, etc. iff they are in the LHC's energy range.

The second one regarding the low energy limit?
So that automatically means the LHC will be absolutely mute about any "ToE". It can support theories with respect to their low energy regime, but nothing else.

Or my general conclusion regarding possible existence (or non-existence) of a ToE
My conclusion is that something like a ToE cannot exist in a physical sense: ...

marcus

Aug24-09, 04:14 PM

Tom I often find your informed opinion on things very helpful but in this case what you say does not make sense to me and I contrast it with the cautious optimism in Weinberg's talk.

...
My conclusion is that something like a ToE cannot exist in a physical sense:
a) you can only "prove", support or disprove a theory in a very restricted sense = in certain regimes
b) a ToE should be able to tell you why it is the ToE; I don't think that ST does only because it is allowed to exist in a 10-D spacetime: it does not tell you why other approaches must fail
c) in a certain sense the discussions regarding duality show that there may be not one fundamental theory but only certain dual descriptions of something we like to call "reality" - whatever that means;
look at QFT: what are the fundamental entities of a "quantum ontology"? state vectors in Fock space and field operators - or path integrals and "trajectories in field configuration space";
look at ST: there are dualities between very different string theories, compactifications etc.
so in terms of ontology this question is undecidable;
d) any mathematical approach to a ToE is not able to prove why this approach must be mathematical at all

I think Weinberg was using a very pragmatic idea of a ToE when he referred to "how nature is". Talking about a predictive theory that appears good to arbitrary high energy.
The commonsense view of science as a process and a community---not as an ultimate.
A theory is a ToE if it acts like a ToE and most of the community accepts it provisionally as such.
And he was saying that string may be irrelevant. String may not turn out to be "how nature is". He suggested an alternative line he is currently pursuing based on asymsafe qg and quantum field theory.

Therefore I think your references to string theory (ST) in your quote may be irrelevant and distracting. Maybe I will take them out and look at the bare bones skeleton of the argument, minus the flesh of that example.

==skeleton argument==
My conclusion is that something like a ToE cannot exist in a physical sense:
a) you can only "prove", support or disprove a theory in a very restricted sense = in certain regimes

b) a ToE should be able to tell you why it is the ToE

c) in a certain sense the discussions regarding duality show that there may be not one fundamental theory but only certain dual descriptions of something we like to call "reality" - whatever that means;
look at QFT: what are the fundamental entities of a "quantum ontology"? state vectors in Fock space and field operators - or path integrals and "trajectories in field configuration space"

d) any mathematical approach to a ToE is not able to prove why this approach must be mathematical at all
==end of excerpt==

Let me think a bit about this
d) is right of course. physical theories are mathematical. the fact that math works to describe regularity in nature is a mystery. but we do not have to address that. A ToE is just a physical theory that works predictively to arbitrary high energy, it does not have to explain all the mysteries.
Like "why does existence exist?" That is a good question but ToE does not have to address it.

c) does not have to worry us. There can be alternative equivalent formulations of the regularities in nature. Sometimes we eventually find that one is better. Sometimes we find a more general mathematics that comprehends both. It is OK. There can still be a ToE even if it comes in several equivalent formulations.

b) pragmatically, I do not see why any physical theory has to explain why it is an adequate theory. If something works and acts like a ToE then it is a ToE.
It does not have to contain a "theory of theories". Science is a communal process governed in part by tradition---and the tradition says that a theory is accepted provisionally until and if a better one is found. That is as good as it gets, in the tradition. All acceptance by the community is provisional. No acceptance is ultimate. So b) is no problem.

a) What you say here is absolutely right, except that we do not know in advance the ultimate limit that we can probe empirically.
Clever ways of testing a model may be invented which surprise us and which go beyond the domain of verifiability that we would have expected.
Pragmatically, the meaning of infinity is "way beyond what anybody expected".
If an theory predicts accurately way beyond what anybody ever thought we would be able to test, because of some clever ways to test that people think up, then it will be acting like a ToE. Predictive out to arbitrarily high energies. It's possible that humans will get such a theory. I don't think that on purely logical grounds you can deny us the possibility. :biggrin:

But I like your argument and think that it is one worth making.

tom.stoer

Aug25-09, 02:44 AM

Marcus,

thanks for the very first sentence of you post :-)

Of course I will try to respond carefully. First of all I was trying to go beyond a purely physical (positivistic) concept of a theory. If we restrict the meaning of ToE to "it predicts experimental results accurately" the all you comments are right - or the other way round - my comments a) to d) are somehow irrelevant.

What I was trying to do is to enlarge the concept of a ToE towards an ontology. That does not mean that we must decsribe nature in terms of things, objects and so an, but at least in terms of structures, laws, relations etc. So w/o knowing in detail what a quantum object "really is", we have a gut feeling, that there is some underlying "quantum ontology".

However quantum mechanics does not tell us what this really is and why it is as it is.

The only theory that tries to go into that direction is string theory. It provides a rather large (and rather un-explored) theoretical framework, which allowes one to restrict its application due to certain consistency conditions. Of course there is still a long way to go - and to be honest I doubt that string theory will do the job - but is is definitly the first theory that at least tries to answer such questions.

Regarding the details:

... Weinberg was using a very pragmatic idea of a ToE when he referred to "how nature is". Talking about a predictive theory that appears good to arbitrary high energy.
OK; here Weinberg restricts himself more than I would prefer; Of course he is right in terms of a scientific program, but I would not call the result a "ToE".

And he was saying that string may be irrelevant. String may not turn out to be "how nature is". ...
Therefore I think your references to string theory (ST) in your quote may be irrelevant and distracting.
see above

d) is right of course ... but ToE does not have to address it.
OK; let's drop d) as it may be too metaphysical and focus on a) - c)

c) does not have to worry us. There can be alternative equivalent formulations of the regularities in nature. Sometimes we eventually find that one is better. Sometimes we find a more general mathematics that comprehends both. It is OK. There can still be a ToE even if it comes in several equivalent formulations.
That's not the point. In terms of purely physical applications you are right, but not in terms of a more fundamental ontology. Look at Maxwells equations: let us assume for a moment that the 4D Minkowski formulation is not known. Then assume that somebody explores the 4D formulation together with Lorentz symmetry, fieldstrength tensor, 4-potentials and gauge symmetry. I would call that a step towards the knowledge what "nature really is".

b) pragmatically, I do not see why any physical theory has to explain why it is an adequate theory. If something works and acts like a ToE then it is a ToE.
It does not have to contain a "theory of theories".
See above; it's especially here where my comments regarding ST apply. As another example I could use Bell's theorem; it is negative in the sense that it tells was what "nature not is". But it reveales some deeper knowledge about the classical and the quantum world and excludes a huge set of "theoretical approaches".

a) What you say here is absolutely right, except that we do not know in advance the ultimate limit that we can probe empirically.

Here we have to be rather careful. If we believe in a theory to be the ToE just because of its support from the LHC, than our belief goes beyond the experimental knowledge.

Assume for a moment that we do not know that GR + QFT are incompatible. Then we could call GR + SM a ToE, simply because all experimental predictions are correct (the problem with 3 generations, Higgs etc. does not apply in the context of argument a). Nevertheless it is no ToE, because:
- we will find inconsistencies at higher energies (argument a)
- it does not explain the particle content, symmetry etc. (arguments b - c)

Of course the LHC could provide mechanisms to test the theory beyond the LHC's energy scale, e.g. due to loop effects that already allowed us to restrict the allowed mass range of the Higgs even if this range is not covered my already operating accelerators. That is not my point.

Predictive out to arbitrarily high energies is a very good starting point. For such a theory I would agree to call it a ToE (of course still with some limitations from b - c). So I think we can agree on a common understanding of a ToE restricted to a pragmatic perspective.

Nevertheless I would like to go beyond that perspective. I know that this is a fundamental clash within the community.
A) we all "agree" that we should use the QM / QFT framework in a pragmatic way - and must not / cannot try to describe nature "as it really is"; photons "are" not the lines within Feynman diagrams, ...
B) All researches trying to understand (e.g.) how QCD works are true believers that quarks, gluons etc. are "real physical entities" - whatever that means - and I am sure sure they would deny that these entities are only mathematical tools to describe scattering cross sections w/o any underlying realistic interpretation.

Of course nobody as of today knows what these "quantum entities / quantum ontology really is", but nevertheless all major research programs are driven by the idea to "understand more about their existence / being".

marcus

Aug25-09, 10:53 AM

I think I understand what you are saying.
There is no clear connection that I can point to, but it made me think of the philosophical seriousness of the physicists of the 1900-1925 generation. What would some of them say to you, if you could talk with them?

There is a tradition of wanting more from physics than a predictive mathematical model and wanting an ontology, which says what really is really there, really.

This is an appealing quest, and probably as old as Anaximander. There is no cure for this desire. I hope there will always people who want this. I am happy to differ with you as to the basic goal and admit you have a good idea.

I will simply tell you mine, for comparison.
If it were possible I would like to see an accurate nonsingular testable dynamics of geometry-and-matter.

In this dynamics, geometry and matter would be (different aspects of) the same thing. So it would be completely natural that they interact and influence each other.

This dynamics would not break down or blow up at singularities. It would continue on through.

I am unprejudiced as to what "dynamics" means. For me, I do not care what the mathematical formalism is. Mathematics evolves in a kind of Darwinian way to meet the needs of physicists and satisfy the rational demands of mathematicians. It mutates, proliferates, survives---the future course of its evolution is not predictable. I do not insist on a Lagrangian although that would be nice. There will be some adequate formalism.

And I find that I do not care if such a thing is final. I kind of hope it is not. And that the people who have it will not see it as final or complete.

For me there is only one revolution, and that is the one we are in. I would love to see it finally carried through, and I relish every step along the way. But since scientific revolutions are so much fun, I trust that this one will not be the last.

tom.stoer

Aug26-09, 02:31 AM

Hey Marcus,

I don't think we disagree; we are just discussing on different levels. I fully agree with your concepts and requirements for a ToE. But as soon as the dust settles I would like to understand more about the Why - not only the How.

Why is spacetime a 4D manifold with SO(3,1)?
What is the reason / origin for the gauge symmetries of the SM
What are the reasons for three fermion generations, flavour symmetry and Higgs?
What are the underlying / unifying concepts?
Why is it This way - and not That way?

So this can be seen as a second level with explanations, restrictions, consistency conditions etc.

Maybe we should not focus on ontology, or rather restrict it to a negative approach telling us what nature Not is.

Dmitry67

Aug26-09, 03:34 AM

Why is it This way - and not That way?

Do you know how Max Tegmark answered that question?

tom.stoer

Aug28-09, 02:00 PM

no; please explain!

Dmitry67

Aug28-09, 03:28 PM

no; please explain!

http://arxiv.org/abs/0704.0646

Stephen Hawking famously asked “what is it that breathes fire into the equations and makes a universe for them to describe?” [93]. In the context of the MUH, there is thus no breathing required, since the point is not that a mathematical structure describes a universe, but that it is a universe

...

As a way out of this philosophical conundrum, I have suggested [12]) that complete mathematical democracy holds: that mathematical existence and physical existence
are equivalent, so that all mathematical structures have the same ontological status. This can be viewed as a form of radical Platonism, asserting that the mathematical
structures in Plato’s realm of ideas, the Mindscape of Rucker [6], exist “out there” in a physical sense [9], casting the so-called modal realism theory of David Lewis [92]
in mathematical terms akin to what Barrow [7, 8] refers to as “ in the sky”. If this theory is correct, then since it has no free parameters, all properties of all parallel universes (including the subjective perceptions of SAS’s in them) could in principle be derived by an infinitely
intelligent mathematician.

tom.stoer

Aug28-09, 05:05 PM

OK, I did neither study nor understand the paper within a few hours, but one first comment is in order: personally I do not think that mathematical and physical "existence" have the same ontological status nor do I believe that (all) pure mathematical entities are physically real. Example: I would not say that the SU(3) "exists" and that this can be proved or derived from QCD.

All I believe is that there is "something out there" independent from our mind - a "physical reality" - simply because of the fact that we all agree on some fundamental experiences / phenomena / measurements which is hardly thinkable with radical idealism = w/o any mind-independent entities or structures. Why should totally independent human minds agree on some structures if not because a mind-independent reality? We all agree on the SU(3) structure fundamental to QCD because there is "something" = a "quark" that forces a human brain to form an "SU(3) idea". We cannot neither separate the physical existence of "quarks" from the "SU(3) idea", nor can we identify them.

I do not know what a quark really "is", nor do I know what the ontological status of the SU(3) "is". I just think that the "physical existence of quarks" is represented by the human mind (or brain - if you want to avoid another discussion regarding mind :-) by something like an "SU(3) structure".

Dmitry67

Aug29-09, 12:46 PM

I strongly recommend reading it. Last summer I was really shocked... I was thinking about it over and over again...

Regarding the "physical reality". Even the either is gone, people are still trying to find tooth wheels behind the curtain. Max Tegmarks hypothesis is not only that ALL mathematical systems have the same physical existence (and therefore an answer to the famous question “Did God have a choice when he created a Universe" is negative) but also that TOE can be expressed in a form of pure equations, it is a pure mathematical system. Everything: the number of dimensions, space, time, particles must emerge from these formulas. No words are required.

tom.stoer

Aug29-09, 01:04 PM

marcus

Aug29-09, 02:08 PM

Finbar

Aug29-09, 04:37 PM

Bee Hossenfelder's comment on Tegmark MathUniverse idea:
http://backreaction.blogspot.com/2007/09/imaginary-part.html

If you are looking to understand the reason why NORDITA institute at Stockholm University hired Bee Asst. Prof. right out of Perimeter postdoc,
then you just have to read that one blog post. Even without other reasons it is enough by itself.

Pretty funny. Tegmart seems to be arguing for dualism...

There exists an external physical reality completely
independent of us humans.

On one hand you have "us humans" on the othere "an external physical reality".

This is retarded. What!? No really? What?

tom.stoer

Aug29-09, 05:44 PM

There exists an external physical reality ... completely independent of us humans.

I would agree, except for the "completely independent ...". There is definitly a physical reality, but if it is independent from any perception is not clear to me. Especially in quantum mechanics it's o longer clear how to make a cut and define exactly this external physical reality.

Compare this to a rainbow: a rainbow somehow exists independent from our perception of the rainbow, but the independent existence reduces the rainbow to a collection of raindrops, light rays and geometrical concepts. This collection could be called its reality / existence, but it can hardly be called rainbow ...

Unfortunately for the physical reality of quantum objects we are not able to say what corresponds to the raindrops, light rays etc. Atoms? quarks? fields? quanta? operators and Hilbert spaces?

Finbar

Aug29-09, 09:04 PM

I would agree, except for the "completely independent ...". There is definitly a physical reality, but if it is independent from any perception is not clear to me. Especially in quantum mechanics it's o longer clear how to make a cut and define exactly this external physical reality.

Compare this to a rainbow: a rainbow somehow exists independent from our perception of the rainbow, but the independent existence reduces the rainbow to a collection of raindrops, light rays and geometrical concepts. This collection could be called its reality / existence, but it can hardly be called rainbow ...

Unfortunately for the physical reality of quantum objects we are not able to say what corresponds to the raindrops, light rays etc. Atoms? quarks? fields? quanta? operators and Hilbert spaces?

external to what?????????

There is only one reality; not two.

There is no cut.

tom.stoer

Aug30-09, 03:53 AM

Do you know the concept of radical idealism?

Kant claimed that there is a "thing-in-itself" which is independend from the human mind, but inaccessible in terms of phenomenology. Nevertheless this "thing-in-itself" is the core of his ontology. Kant was already on the way to idealism.

Other philosophers claimed that there does not exist any mind-independent reality. Berkeley for example claimed that there is no mind-independent reality. For Berkeley there is no existence that is not held by the mind. All existence boils down to "being poerceived". The continuous existence of the universe is guarantueed due to its continuous perception by god.

Please answer the following question: "Does the moon exist even if nobody looking at it?"

If you answer is "yes", then you tend to a realist ontology which means that you believe in a reality that is external and more ore less independent to you. That does not automatically mean that the moon you are talking about (you perception of the moon) and the "moon-in-itself" are the same entity. They are not!

If your answer is "no" then you tend to an idealist ontology which means that you believe in the moon's existence basically within your mind. Radical idealism droped the idea of a "moon-in-itself", not only as accessible but even as existing. So the moon is reduced to a collection of thoughts.

(Radical) positivism is not so different from radical idealism. It says that all reasoning is based on experience and perception and that you cannot go beyond that experience to some metaphysical concept like a "thing-in-itself", ontology, existence etc. Positivism is often seen as a philosophical interpretation of quantum mechanics. Q.M. is then seen as a science that makes physical predictions about measurements, but not about existence, ontology etc. If you take Feynman's reasoning about philosophy seriously ("should up and calculate") you tend towards positivism / idealism.

Now the problem for me is that even if I deny that q.m. can tell us anything regarding "reality", I have the feeling that there is something behind this "empirical film" of the world. The reason is very simple: I believe that all physicists (not only here on earth) come to more or less the same conclusions if they study physical experiments. But as their minds are independent entities (you can study Bell's inequality and Aspects experiments together with Axpect's group here on earth and you can do it in the Andromeda galaxy) this identical conclusions on the meaning of q.m. is a hint towards a mind-independent "reality" beyond the different "empirical films".

This mind-independent reality is not (necessarily) same same as the mind-dependent one. In terms of Kant I would say that the mind-dependent reality is something like an (entangled) world of Hilbert state vectors. Mind-independent reality is inaccesible to us as we cannot avoid the filtering of the reality by our "mind-internal processes".

So if you can roughly agree that the moon exists even if you are not looking at it then you agree that there is an external reality - the moon-in-itself. This external reality has an independent existence - it will stay as it is even if all physicists stop looking at it and thinking about it. And it is the very entity that guarantuees that if we re-start looking at it that we will again see the "same moon".

I agree that the term "cut" is problematic. It's more a paradigm shift when you try to move from the q.m. description of the world to the thing-in-itself (or whatever you prefer; I would not call it that way as it seems that I tend to Kantianism).

The next problem is that I do not know to which entity the external q.m. reality boils down if I start to remove the "empirical film". I know that the rainbow reduces to something like a collection of raindrops etc - but as I said this is no longer a rainbow the very concept of a rainbow must include its perception.

Now we come to the problem of the q.m. meaning of "external". Assume for a moment that the mind-dependent reality of the q.m. world is the Hibert space. Then it's unclear how to define "external to us" as I would agree that we are of course part of a larger Hilbert space (the Hilbert space of the observed q.m. entity plus the laboratory plus the physicist).

Now look at an object that was hidden beyond the particle horizon of the universe and that becomes visible right NOW caused by the expansion of the universe (neglect inflation = neglect the fact that the object was visible some times earlier). I truly believe that this object (as it is perceived by us) has a mind-independent existence external to you and me - and "is" therefore a real physical entity (thing-in-itself). Its causal history is independent, it is not entangled with "our sector of the Hilbert space", it has never been perceived by us.

So my conclusion is a) that there is a mind-independent, external reality but b) that we cannot even know about the very concept / meaning / notion of its existence. We do not know to what the "rainbow" reduces - but we are definitly sure that its reduction causes it to lose its "rainbowness".

Dmitry67

Aug30-09, 08:22 AM

Before I start reading: one central question is if and how the ToE explains its own uniqueness.

Assume for a moment that the SM + a UV complete version of GR would be the ToE. How would this theory e.g. explain the SU(3) symmetry of QCD? the 3 families of fermions? the Higgs boson? Why not SU(4)? why not 4 generations? ...

So if the ToE is a mathematical framework - why is she exactly THIS framework and not something else?

Or do you say that all mathematical structures have the same "degree of existence". Then why do we observe in our universe an SU(3) structure and not SU(4)? Doesn't this idea of structures "having equal rights" lead to something like a mathematical multiverse w/o any explanation which structure comes to "true physical existence"?

Max's article is full of interesting ideas, for example, that WHOLE is simpler then a part of it. Like number 488583299394839304 is more complicated then the set of ALL integers.

So, returning to your question, there are several levels of TOE. *ANY* mathematical system IS a Universe (he calls it Level 4 Multiverse) For example, Conway game of Life IS a Universe. Including ours. There is nothing special about SU(3). Why not SU(4)? Well, may be there is a Universe with SU(4), other types of particles, different types of beings there. But more likely almost all other universes are sterile, because they can not generate intelligent life - we know how many conditions must be satisfied to create us, humans.

It leads to a very interesting question. Is TOE of our universe the simplest non-sterile universe?

tom.stoer

Aug30-09, 06:00 PM

*ANY* mathematical system IS a Universe (he calls it Level 4 Multiverse) For example, Conway game of Life IS a Universe. Including ours.
I would agree if we talk about platonism where all mathematical structures have an own existence. The material world = our universe is a manifestation of this existence. Plato thought that the material world is a kind of image or shadow of the ideal world. But Plato never thought - and I would not agree - that (the other way round) all ideal worlds must have a physical manifestation. (This is only a remark and not really required in our discussion).

There is nothing special about SU(3).
Of course there is something special about SU(3). It's the the only symmetry structure for which a physical manifestation in strong interaction is KNOWN. SU(4) might be possible and might be realized in "other universes", but that is SPECULATION.

Why not SU(4)? Well, may be there is a Universe with SU(4), other types of particles, different types of beings there. But more likely almost all other universes are sterile, because they can not generate intelligent life - we know how many conditions must be satisfied to create us, humans.
QCD with a different number of colors (e.g. NC=2) is qualitatively identical to our world with NC=3. Many lattice gauge simulations use two or three flavors (NF=2,3) only and are able to reproduce the hadron spectrum within a few percent. As far as I know QCD with NF=8 which corresponds to a heavy fourth fermion generation cannot be ruled out experimentally.

Is TOE of our universe the simplest non-sterile universe?
What do you mean by simple?

It seems to me that instead of a physical multiverse (in the context of string theories) a new speculation of mathematical multiverses and their physical manifestations is proposed. I would say that a candidate for a ToE should do something like that: propose a kind of framework for theories and deduce an idea how "nature" selectes one possibility. From what I understand the selection principle is missing - and this defect is promoted to a feature of the whole approach.

Imagine that pure QCD + UV completion of GR is the ToE. Then I would expect that within some framework, e.g. SU(NC) with NF plus UV completion of SO(D-1,1), one can answer the questions "why is NC=3?", "why is NF=6?" and "why is spacetime four-dimensional, i.e. D=4)".(Of course this candidate theory is wrong as it predicts the non-existence of electro-weak interactions.) Theories as we know them today are not able to answer these "why-questions". String theory tried for two decades but surrenders now by proposing the idea of the landscape or multiverse.

And this is my point: If you (or Tegmark) replace the ontological meaningless idea of physical multiverses by the (even more) meaningless idea of mathematical multiverses plus their possible physical manifestation w/o any idea for a selection principle, then the whole discussion is "void". If nobody can tell me why nature selected SU(3)C, then it is no answer to say "nature did not select anything but realized all SU(N)C-universes in a random and democratic way - and eventually casted me into one of them where NC=3." This is metaphysical speculation and has nothing to do with science.

Don't get me wrong: I like the multiverse(s) as a set of candidate theories, but I expect some kind of framework plus selection principle to answer the "why-questions". If the latter does not exist or emerge, then the whole approach is meaningless and useless.

Remark: My impression is that the "why-questions" were not so important for a couple of decades because physicists hat a lot of work to do after the QM revolution (inventing QFT, renormalization, current algebra, soft pions, standard model, chiral perturbation theory, lattice gauge theory, ...) - and perhaps these "why-questions" have simply been ignored; therefore we are not used to ask and to answer them. But as we now try to figure out what a ToE is, how it can look like (logically, mathematically, physically, ontologically?), what the requirements and preconditions are etc., we must focus again on these questions and cope with them, otherwise we are lead astray.

Finbar

Aug30-09, 07:42 PM

Dmitry67

Aug31-09, 01:08 AM

1
Of course there is something special about SU(3). It's the the only symmetry structure for which a physical manifestation in strong interaction is KNOWN. SU(4) might be possible and might be realized in "other universes", but that is SPECULATION.

2
As far as I know QCD with NF=8 which corresponds to a heavy fourth fermion generation cannot be ruled out experimentally.

3
What do you mean by simple?

4
From what I understand the selection principle is missing - and this defect is promoted to a feature of the whole approach.

1,4
I believe you have the same misconception people usually have about MWI. People tend to say “ok, there are different branches, but why *I* am in this particular branch?” while all branches are symmetric and “you” in all branches are asking the variations of the same question “why I am in this branch?”

Exactly the same we have here. What do we call “real”? I take an apple. I touch the surface, I sense its smell and taste. It is all about the correlations between output signals from my brain (I give command to muscles to take an apple) and input signals (smell, taste).

Now imagine structures in different non-sterile Universes. Intelligent being there would definitely call their environments “real” for the very reasons I described above. They will also call other worlds “imaginary”. Finally these beings will ask your question: why my world is SU(3)? Or why my world is 93-dimensional? Why my geometry is non-commutative? Or why space in my world is made of pixels (is asking some creature living in the Conway’s game of life world)

So I not only refuse to answer your question about the selection rule, but I (after Max Tegmark) insist that there should not be any selection rule!

2
I’ve heard that neutrino oscillation experiments had ruled out the 4th generation

3
Lets say the total length of all formulas. I know, it is not perfect as it depends on the mathematical language used.

tom.stoer

Aug31-09, 01:36 AM

Regarding 1,4:
If you insist in this mathematical mutiverse w/o any selection rule then we have to agree that we don't agree :-)

Regarding 2:
This argument is forbidden im my ToE since it does not contain neutrinos and weak interactions :-)
Seriously: thanks for the information; do you have a reference?

Regarding 3:
After having discussed 1 and 4 this is no longer important :-)

tom.stoer

Aug31-09, 01:56 AM

Finbar,

I agree that there is only one physical reality. I don't like the dualist view. Dualism with mind-independent reality is awkward since it does not allow us to describe the interaction of mind and matter (or whatever the two entities are). As soon as we are able to decsribe this interaction we are forced towards monism.

But nevertheless there seem to be different layers of what we call reality; one layer is our mind.

Look at the rainbow; you have three different "views":
(a) the rainbow as it is perceived
(b) the physical constituents of the rainbow = the raindrops, lighrays etc.
(c) the mathematical description in terms of geometry etc.

(a) is unthinkable without YOU!
(b) is rather clear for the rainbow but not known for the real quantum world; our all-days language is no longer suitable for describing the quantum reality
(c) does "exist" even if you and the raindrops does not.

Now let's assume for a moment that the mathematical Hilbert space is not only a description of the reality but IS the reality (bad idea: we immediately face the problem of the collapse of the wave funtion which is not described in terms of quantum mechanics; so this reality is incomplete). In that case we agree that there is one reality which IS the Hilbert space - done!

I think the major step forward is that we agree that there is a reality and that we do not insist on idealism or positivism. The problem then is that we do not know what this reality IS.

If we would instead think of the q.m. formalism as a pure description only and if we say that there IS nothing else but this description (no external reality), then we omit the measurement problem, but we are left with the situation that after all we cannot answer the question "why do all physicists use the same description?".

In the very end I believe that every physicist tends to realism. After all calculations are done and after the experimental data have been analyzed he/she wants to know what there really IS (including himself/herself)

Fra

Aug31-09, 02:02 AM

Tegemark's reasoning is not appealing to me either and I didn't follow this discussion but I just jump in with a comment on one thing, a simple response to one specific question from my point of view.

All I believe is that there is "something out there" independent from our mind - a "physical reality" - simply because of the fact that we all agree on some fundamental experiences / phenomena / measurements which is hardly thinkable with radical idealism = w/o any mind-independent entities or structures. Why should totally independent human minds agree on some structures if not because a mind-independent reality?

IMHO because what you think of as observer/mind independent structures, is emergent as a result of observers/minds/systems are interacting. As a form of negotiation process.

The why and HOW this process occurs, and what the result is would I think answer alot of the previous questions as to "why this symmetry and not that one". There is no currently available argument but the lineout is along the lines that, what equilibrium structures would be expected on a market where the players are rational to the extent possible?

In such a game, there is a group selection pressure in the sense that you can not largely violate the negotiated "rules" and stay in equilibrium.

I think physical law might eventualyl be understood as such "negotiation process" where matter are the players. There specrum of laws/rules and players population the equilibrium would thus expecte to be connected.

/Fredrik

atyy

Aug31-09, 02:15 AM

"why do all physicists use the same description?"

Zurek, http://arxiv.org/abs/0707.2832

tom.stoer

Aug31-09, 02:22 AM

Fredrik,

I am not sure if I understand.

If it is a collection of minds that negotiates then I have to ask "how does this negotiation work?". OK, I don't think that you mean this.

If it's matter (whatever matter IS) that negotiates, then the questions are a) how this "negotiation" differs from "interction" and what (which "framework") sets the rules for the negotiation?

Or do you think that the physical laws emerge as a negotiation process? Then again: what are the rules for the negotiation and where do they come from?

Or do you say that only a description of the fundamental reality emerges from this negotiation? If so, the description is created by us humans. Therefore other communities of intelligent life could come to a totally different structure than SU(3) but still describe the same reality. If this is the case I would simply call this a "dual description". In that case again I would ask what is the reality behind this description.

ATTENTION: There is one general argument not to take the descriptions too seriously as reality per se. If you identify the description with the reality, then every time you are forced to change the description, you automatically destroy your ontological basis. During the paradigm change from classical to quantum physics the description changed - but certainly not the reality!

Fra

Aug31-09, 03:20 AM

If it is a collection of minds that negotiates then I have to ask "how does this negotiation work?". OK, I don't think that you mean this.

Yes I'm not talking about human minds - it's just by analogy.

If it's matter (whatever matter IS) that negotiates, then the questions are a) how this "negotiation" differs from "interction" and what (which "framework") sets the rules for the negotiation?

There is no difference. The framework of negotiation is subjective, or relative to the observer.

Or do you think that the physical laws emerge as a negotiation process? Then again: what are the rules for the negotiation and where do they come from?

Yes, both interaction as per some law, and the law itself are different hierarchies of evolution in my abstraction. The only difference between a state in the normal sense and law, is it's confidence or inertia.

Or do you say that only a description of the fundamental reality emerges from this negotiation? If so, the description is created by us humans.

? why? I wouldn't say so, because the negotiators are not humans, it's physical systems, ie matter. Objectivive stable law, corresponds (in my view that is) to equilibrium at the corresponding level. Usually, it's only this most stable level where the evolution is not distinguishable that we would usually label "law".

So the question, what are the rules of negotiation? Well, that is the same as to ask what are the rules that selected the laws of nature. I do not have an answer yet. I just describe here a general point of view, a suggestion of a research program.

Ariel Caticha has a similar, but less radical view, where he thinks the laws of nature are derivable from the rules of rational inference in an information theoretic approach. But he works in a more objective context that I. He also doesn't reconstruct the continuum.

What I have in mind, as the program is to reconstruct probability theory, from a discrete poitn of view, and then argue that there exists natural rational measures of information divergence due to uncertainty that is the basis for the physical action of the least action principle. In this view, all "measures" will by construction get a kind of mass(complexity), that works as an inertia in negotiation processes.

The heave opinon will have large impact than the light one.

Combine this with systems of probability spaces that are related by transformations, leads to a measure-complex consisting of several related discrete proability spaces (discrete refers both to event index and probability value) and physical actions are then derived from the inference properties of this system.

So one such system might correspond to a physical system, say an elemetary particle. The mass is thus related to the complexity.

Also the internal transforamtions are those that leaves the complexity (amss) invariant and also leaves the communication interface to the environment invariant. The degrees of freedom left are tamed by assuming he internal equlibration is that which is most self-preserving - just like the human brain is constantnly reorganising inputs in the way that's assume to in its' interest.

This also aims to explain the origin of mass as a kind of game, where accumulation of mass is like accumulation of confidence. There is a kind of argument that this is simply self-presevation, those systems whose actions doesn't try to keep/increase confidence in the current structure will not survive - and thus such measures-complexes (matter) are not observed in nature other than transiently.

/Fredrik

Fra

Aug31-09, 03:58 AM

Or do you think that the physical laws emerge as a negotiation process? Then again: what are the rules for the negotiation and where do they come from?

This touches upon Smolins ideas on laws beeing a result of evolution. Someone asked him that, then must their not be some meta laws of this evolution whose origin you would similarly question? He didn't give a clear answer.

But in my view that, I'd say no, there is no such laws. Instead my idea is to argue that the laws are emergent from a point where no laws at all are distinguishable, at this point the objection itself dissapears. I associate this to the *inside view* of a "TOE level" (total unification) - this is totally unlike the TOE level that we seek in an high enery accelerator experiment. This is what I would call a external view of the "TOE action".

/Fredrik

Dmitry67

Aug31-09, 05:53 AM

Regarding 1,4:
If you insist in this mathematical mutiverse w/o any selection rule then we have to agree that we don't agree :-)

Regarding 2:
Seriously: thanks for the information; do you have a reference?

2
I have found only this (sorry for quoting Wiki, I remember I have seen it somewhere else too):
http://en.wikipedia.org/wiki/Neutrino#Types_of_neutrinos

Measurements of the Z lifetime have shown that the number of light neutrino types (with "light" meaning of less than half the Z mass) is 3

1,4
ok, lets agree on disagreement.
But to understand your disagreement, could I ask you a question about what is "real".

Are virtual particles "real"?
A) Yes, like the regular ones. They just don’t have 'free' energy. But on the short time intervals there is almost no difference.
B) No, only real particles are real. Virtual particles are just a mathematical method of calculation of interaction between real particles.
C) Both real and virtual particles are just mathematical methods of calculation of the correlation between macroscopic events. Only macroscopic events are real.
Note: Hawking radiation and Unruh effect (so different accelerated observers do not agree on the number of ‘real’ particles) strongly suggest A) or C), not B)
Note 2: In MWI there are no particles at all, but question is still valid if we talk about wavefunction.

Finbar

Aug31-09, 08:08 AM

tom.stoer

Aug31-09, 04:44 PM

@Dmitry67,

Regarding the reality of virtual particles: I think this is confusing, as strictly speaking there are no real particles at all! A particle has to interact with some detector in order to be detected. All those interactions are described by the exchange of virtual particles, so the detector registers virtual particles only. The real particle that escapes to infinity w/o absorption or whatever is invisible to us.
=> C) = mathematical tools
[the distinction between real and virtual particles comes from the distinction between the quantum process subject to experiment and the measurement itself; in the process only virtual particles are involved; in the measurement we register the asymptotic, outgoing real particle; this is a framework for doing certain calculations - quite successfully - but not a solid basis for an ontology]

Regarding the wavefunction: I would not say that a wavefunction is "real". If it were real then the "collapse of the wave function" during a measurement would be real as well - and I don't like this idea :-)
As an alternative you could try to construct two different "evolution operators" in QM; one is the well-known unitary time-evolution operator U(t,t°), the second one is a non-unitary R which - when applied to a wave function - forces it to collaps to the eigenstate corresponding to the eigenvalue that has been measured. R is applied to describe the measurement process. This has been proposed by Penrose - and I don't like this idea, either.
=> C) for the wavefunction as well

What is "real"?
Honestly speaking I don't know. What I was trying to explain is the following:
A) QM as it is understood today mainly serves as a framework that predicts experimental results; with this interpretation you will never run into difficulties when talking about reality; you simply deny that QM describes reality but you insist on the position that QM *only* predicts experimental results.
B) I do not see anything in the QM framework that could be "real", strictly speaking. Are Hilbert spaces real? Path integrals? I don't think so. They are just tools to predict experimental results. This is true for classical physics as well. Of course I would say that "spacetime exists". But I would not say that" spacetime is a four-dim. pseudo-Riemann manifold"; strictly speaking I would say that "spacetime is described mathematically by a a four-dim. pseudo-Riemann manifold"
C) Nevertheless I am convinced that there is something beyond this abstract descriptive layer that is indeed real! The moon is real - and a pair of entangled photons is real as well. They exist even if we don't look at them, even if we do not measure them. They have an existence that is independent of ours - and of our descriptions. The reality of the world does not change because we are changing the methods to describe it. Going from Newton to Einstein did not mean that the reality or the existence of spacetime has changed; only the description has been improved to some degree.
D) So I am a realist in the philosophical sense. I believe that there is something like "real physical entities". They need not be known entities like "pointlike masses" or "fields". With our physical and mathematical tools we are coming closer and closer to a description of this reality; but it will remain a description, an image, a model, not the reality itself. I do not identify reality with its description.

tom.stoer

Aug31-09, 05:11 PM

Tegemark's view is that there existence some (c) which IS (b) and that he can ignore (a).
So let me say this in my own words just to make sure that I understood everything correctly.

Plato says that it's the "ideal triangle" that exists primarily. All drawings of triangles etc. are only secondary shadows or incomplete models (Allegory of the cave). I would agree with him in the context of mathematics, i.e. for mathematical entities like (e.g.) triangles.

Aristotle says (just the opposite) that the ideal triangles are only secondary abstractions of drawings, physically existing triangles etc. I do not agree with him in the context of mathematics, but e.g. in sociological contexts, i.,e, for terms like "goodness" as a secondary abstraction of several good deeds.

Now comes Tegmark and says that we can avoid both dualistic interpretations and find a monistic one that goes as follows:
1) there is a rather powerful mathematical framework which allows us to describe quarks q, q', q'', ..., interaction processes of quarks p(q, q', q'' ...) etc.
2) there is some reality populated by Quarks Q, Q', Q'', ... interacting in Processes P(Q, Q', Q'', ...)
3) instead of saying that (2) is "the reality" and (1) is "its description", this framework allowes us to write q = Q, q' = Q', q'' = Q'', p(q, q', q'' ...) = P(Q, Q', Q'', ...).
The "=" does not mean "represents" or "describes" but "IS" in the sense of "is identical with".

So it's not only that we have e.g. the situation that two Quarks Q and Q' are identical Q=Q', which is mapped to the description as q=q', but that the description q of the Quark Q and the Quarks Q itself are identical. (of course I don't want to say that the reality is indeed populated by quarks; it's just an example; it could have used malt whisky as well)

Is it that what he says?

If yes (and if one can get rid of the multiverse) this is fascinating and shocking!

moniker2

Sep1-09, 01:27 AM

Would you ever consider a Toe with imaginary units of energy, time and matter?

Dmitry67

Sep1-09, 04:26 AM

Would you ever consider a Toe with imaginary units of energy, time and matter?

Time units are already imaginary in SR :)
Also I expect LHC to confirm Standard Model on high eneries - instead of some new particles I expect negative probabilities become inevitable.

Dmitry67

Sep1-09, 04:31 AM

If yes (and if one can get rid of the multiverse) this is fascinating and shocking!

Yes, this is what he says: mathematics does not DESCRIBE the reality, it IS reality.

But if you do this step, then the next step you unavoidable. If some mathemetical system describes OUR Universe, then why it is special? "What burns fire into these formulas?" (c) Hawking.

If Mathematical system IS physical reality then no special agent is needed for the formulas to "live". Hence, any (correctly defined) mathematical system MUST BE a universe.

Chronos

Sep1-09, 05:01 AM

The LHC is not even remotely capable of the power levels routinely generated by grb's, supernova, inspiralling neutron stars, etc. I doubt anything very novel will emerge from it. Information theory might be a more powerful instrument. If our fundamental assertions are correct, computational results should be consistent with observation. If not, something is either missing, or incorrectly modeled, imo.

Dmitry67

Sep1-09, 05:14 AM

The LHC is not even remotely capable of the power levels routinely generated by grb's, supernova, inspiralling neutron stars, etc.

The temparatures in such processes is only few billion degrees.
LHC gives MUCH more then that!

marcus

Sep1-09, 08:06 AM

The temparatures in such processes is only few billion degrees.
LHC gives MUCH more then that!

Dmitry, a square kilometer receives several million particles a year with energies in excess of 1000 TeV.

That is 10^15 eV and if one were to convert that to temperature in the usual way one would say 10^19 kelvin. Ten billion billion kelvin.

But are there processes currently going on in our galaxy that you would characterize as having a temperature of ten billion billion kelvin?

I guess my point is that temperature can be a tricky concept because the particles are produced by non-equilibrium processes. We have this mental reflex to convert particle energies to temperature, but it does not always give the right intuitive understanding.

Cosmic ray particles with energies in excess of 10^20 eV have been observed. If one converts that in a kneejerk way to temperature, one would say 10^24 kelvin. This is more than a "few billion degrees".

It is a quadrillion billion degrees.

But does that conversion to temperature really help you understand cosmic ray particles, or the processes that produce them?

Dmitry67

Sep1-09, 08:16 AM

Yes, but there is no clear explanation for such rays.
So yes, they have been observed.
For example, in supernova explosion temperature is only 10**11 - 10**12 K

marcus

Sep1-09, 09:38 AM

I'm not sure you understand my point. I am questioning the usefulness of assigning a temperature to a supernova and then expecting that temperature to characterize the energies of the cosmic rays accelerated by some nonequilibrium supernova processes. For example see this paper published in Nature.

http://arXiv.org/abs/astro-ph/0411533
High-energy particle acceleration in the shell of a supernova remnant
H.E.S.S. Collaboration: F. Aharonian, et al
9 pages, 3 figures, published in Nature
(Submitted on 18 Nov 2004)
"A significant fraction of the energy density of the interstellar medium is in the form of high-energy charged particles (cosmic rays). The origin of these particles remains uncertain. Although it is generally accepted that the only sources capable of supplying the energy required to accelerate the bulk of Galactic cosmic rays are supernova explosions, and even though the mechanism of particle acceleration in expanding supernova remnant (SNR) shocks is thought to be well understood theoretically, unequivocal evidence for the production of high-energy particles in supernova shells has proven remarkably hard to find. Here we report on observations of the SNR RX J1713.7-3946 (G347.3-0.5), which was discovered by ROSAT in the X-ray spectrum and later claimed as a source of high-energy gamma-rays of TeV energies (1 TeV=10^{12} eV). We present a TeV gamma-ray image of the SNR: the spatially resolved remnant has a shell morphology similar to that seen in X-rays, which demonstrates that very-high-energy particles are accelerated there. The energy spectrum indicates efficient acceleration of charged particles to energies beyond 100 TeV, consistent with current ideas of particle acceleration in young SNR shocks."

If you make a simpleminded conversion of "beyond 100 TeV" to temperature, then it does not make sense. The simpleminded conversion of 10^14 eV would be 10^18 kelvin. That is one billion billion kelvin.
No one supposes that the supernova explosion is characterized by a temperature of 10^18 kelvin. In fact it is an intricate process, or combination of processes, some of which do not have a well-defined temperature.

One would not say that the supernova has a temperature of "beyond 10^18 kelvin", and yet it apparently produces cosmic ray particles accelerated beyond 10^14 eV.

Something more recent on this general topic (supernova remnants and cosmic rays) is a 2008 white paper:
http://arxiv.org/abs/0810.0673

Dmitry67

Sep1-09, 11:03 AM

marcus, ah, I see, I agree.
BTW, any news about how such particles violate GZK-limit?

marcus

Sep1-09, 11:30 AM

BTW, any news about how such particles violate GZK-limit?

Dmitry, I think that the specialists in UHECR say that the ultra-high-energy particles come from comparatively near and have not been traveling long enough for them all to interact with the CMB photons. I don't have any recent news and am not so well-informed about this, so we should check to be sure.

As I recall, they suspect that cosmic rays are either generated in our own galaxy or come from comparatively nearby active galactic nuclei (AGN).

Yes, I checked---Wikipedia gives some numbers.
The GZK cutoff is 5 x 10^19 eV, and it only applies to distant sources---the mean free path for the reaction with the CMB is 160 million light years.

160 million lightyears is fairly close to us. There are enough AGNs within that range. If I remember there used to be a puzzle about GZK, somebody had seen too many UHECR, they thought. Then the Auger observatory found there were not too many. The UHECR could be explained as coming from nearby AGN. So this puzzle was cleared up. I think Auger even pinpointed some nearby AGN sources of cosmic rays (though not of this ultra high energy.)

Finbar

Sep1-09, 12:51 PM

If yes (and if one can get rid of the multiverse) this is fascinating and shocking!

Yeah you can't say QM describes a mathematical reality unless you use the many worlds interpretation. Otherwise clearly QM is not a description of reality at all as one does not ever measure the wave function. So one cannot get rid of the multiverse. In that case it is only the sum of these worlds that can constitute a mathematical universe.

Vanadium 50

Sep1-09, 01:28 PM

I think Auger even pinpointed some nearby AGN sources of cosmic rays (though not of this ultra high energy.)

That correlation has either weakened or disappeared, depending on who you talk to.

marcus

Sep1-09, 01:53 PM

That correlation has either weakened or disappeared, depending on who you talk to.

I'm glad to learn of this! Do you have any paper or news item that tells about it?

tom.stoer

Sep1-09, 02:31 PM

Yes, this is what he says: mathematics does not DESCRIBE the reality, it IS reality.
But if you do this step, then the next step you unavoidable. If some mathemetical system describes OUR Universe, then why it is special?
This question stillmakes sense.

You should take into consideration that for many known mathematical frameworks you can construct a meta-framework from which the individual frameworks can be derived. In that case the meta-framework can provide a selection rule.

Dmitry67

Sep1-09, 02:42 PM

Vanadium 50

Sep1-09, 10:49 PM

I'm glad to learn of this! Do you have any paper or news item that tells about it?

Glad? Indeed. Why?

The most positive interpretation comes from Auger themselves: see their presentation at ICRC 2009 in Lodz. They say that the correlations have "not strengthened" or "weakened", despite having added more data to the analysis.

Others did the natural thing and subtracted the new numbers from the old numbers to look at the correlation in just the events they added. Nothing much there.

marcus

Sep1-09, 10:54 PM

Glad to get new information about an interesting question like the origin of UHECR.

The most recent thing I've seen about this is April 2009
http://arxiv.org/abs/0904.4277
Correlations between Ultrahigh Energy Cosmic Rays and AGNs
Glennys R. Farrar, Ingyin Zaw, Andreas A. Berlind
(Submitted on 27 Apr 2009)
"We investigate several aspects of the correlations reported by the Pierre Auger Observatory between the highest energy cosmic rays (UHECRs) and galaxies in the Veron-Cetty Veron (VCV) catalog of AGNs. First, we quantify the extent of the inhomogeneity and impurity of the VCV catalog. Second, we determine how the correlation between the highest energy Auger UHECRs and VCV galaxies is modified when only optically-identified AGNs are used. Finally, we measure the correlation between the published Auger UHECRs and the distribution of matter. Our most important finding is that the correlation between UHECRs and AGNs is too strong to be explained purely by AGNs tracing the large scale distribution of matter, indicating that (barring the correlation being a statistical fluke) some substantial fraction of UHECRs are produced by AGNs. We also find that once we take into account the heavy oversampling of the VCV catalog in the Virgo region, the lack of UHECR events from that region is not incompatible with UHECR having AGN sources."

If you have a link handy to some particular abstract from the conference you were talking about, I'd be glad to give a look.

moniker2

Sep2-09, 07:22 AM

Maybe it's time to redefine temperature.

tom.stoer

Sep2-09, 03:17 PM

Could you explain your motivation, why do you want to find some "selection rule"?

Selection rule adds complexity. Number 456 contains more information then ALL integers, because you can ask "why 456? what is selection rule?" For ALL integers you dont need a selection rule.

The explanation is as follows:

I believe that we are living on one of many possible worlds. Possible means logically or mathematically possible = (at least) consistent.

As I said I think that a universe with (e.g.) a fourth heavy fermion generation would be "possible" and would not differ so much from ours. So we must take this into account when we study candidates for a ToE.

Then I believe that (even if you insist on some kind of a multiverse) not ALL but only a certain SUBSET of all possible worlds exist "somewhere". Of course I do not know what this subset is but I strongly believe in this subset.

Reason 1: I don't like the multiverse idea, because it has too much metaphysical ballast and does not satisfy Ockham's razor criterion; I don't believe in an entity that is in principle invisible, not measurable and therefore unphysical. Compared to the multiverse one selection rule seems to be much simpler and much easier to believe in (at least for me).
Reason 2: All discussions regarding the multiverse idea (many-worlds interpretation, landscape) I ever participated in came sooner or later to a point which I would describe like "I cannot explain why it's this way or that way - and therefore it's both ways!" That's not a sientific argument but an excuse only.
Reason 3 - and this is the most important one: even if you insist on the multiverse idea, it is by no means clear why ALL logically consistent ToEs should be physically real - why not only a certain subset? Compare it to evolution: not ALL possible species are alive, but only a certain subset. Why is this? Simply because there are selection rules (not hand made, but external to the species' ToE framework = the DNA, namely the environment) which suppress or constrain the evolution. In our case this could be some meta-theory, but nevertheless it must not be excluded.

So this selection rule could restrict the number of real worlds to just ONE, or it could drive an evolution of universes such that we are living in a TYPICAL one.

(Smolin's idea was that a universe spawns children from black holes, so a selection rule is that a typical universe is one in which the numer or density of black holes is maximized such that as many baby universes as possible are spawned - I don't think he was able to define this mathematically and prove why our universe nearly maximizes the number of black holes).

Finally I would like to explain reason 4 - even if I did not study the paper in question in all details: From a philosophical point of view I still do not see how the concept of a DESCRIPTION of a world is converted into the WORLD itself. I still believe in a kind of dualism, namely that the world and its description are two different "entities". Therefore the mathematical frameworks do not exist on the same level as the worlds.
Of course there is a sketch of a proof: The mathematical framework is eternal and exists "forever". It does neither exist "in time" nor "in space". But a universe can be created out of "something" and eventually it can fade away. Therefore the lifetime of a universe could be finite, whereas the lifetime of the corresponding mathematical framework is certainly not (homework: when will the prime numbers die?)
If you believe that the prime numbers will never die, then
a) either the universe (by similar reasons: all universes!) is (are) eternal, which means that only eternal universes are allowed, which is a selection rule!
b) or the prime numbers exist in some "outer space" = some meta-theory in which the "universes" = ToEs are embedded. In that case the eternal framework turns again into an eternal description of a mortal world, which proves that the two entities in question do not exist on the same level.

(Logical positivists grounded some of their disproofs in a mismatch of categories. E.g. they claimed that the color red is not identical with a certain wavelength, but is its representation. I have the feeling that this concept for a ToE is vulnerable due to similar reasons).

My conclusion is that I am still not convinced that the entity "description of the world" is identical with the "world" it describes.

Last but not least I would like add an idea how ToEs could be categorized:
- first requirement is that the ToE incorporates all known interactions in some way, e.g. as low-energy effective theories
- second requirement is that the ToE is a consistent mathematical framework, i.e. it must be mathematically well-defined
- third requirement is that the theory must post-dict at least some known facts like the standard model gauge symmetries, number of generations, number of space-time dimensions etc.
- forth requirement is that the theory must predict new phenomena which should be (at least in principle) falsifiable by experiment
A (meta) requirement) for a (meta) ToE is that the theory in question can at least support why she is the ToE. That means if the ToE contains a certain mathematical structure, there should be an explanation in terms of deeper structures or insights why this structure MUST be contained. This is subtle, of course. EXample: if the ToE is grounded on local gauge symmetries, I would like to know WHY.

moniker2

Sep3-09, 01:37 AM

Maybe you can use Knot theory to satisfy Ockham's razor criterion in the multiverse idea.

Dmitry67

Sep3-09, 02:13 AM

Tom,

Regarding 1,2,3 and Occams razor. In informational sense, “information should not be multiplied unnecessarily”. When we build something, we add building blocks, adding new information an every step. That is why every new stone you put in the building must be well justified. However, using this method you can add only finite number of stones/entities. You can’t define integers by providing a complete list, right?

When we manipulate with infinite numbers of entities we go in the opposite direction: we start from the Universum, and then remove something. Each removal adds new information (and list {12438, 59859599, 858585, 77} contains MORE information than a list of ALL integers), so each removal must be justified.

It seems you understand it and for that reason you call a “selection” rule (selection – taking one from many = removing others). Again, you are not asking how to justify the creation of OUR universe( that would be natural for one going from nothing to the Universum), you seek the justification of removal for the others. So we are on the same page.

But: if we go in the opposite direction, from the Universum, then any REMOVAL adds new information and hence is a subject of Occams razor. Going from nothing to the Universum we must justify any addition, going back we must justify any removal. You mentioned Occams razor and on the very next step started inventing NEW entity which you call a “selection rule”. Do you agree with my logic?

So Occams razor is the very reason I believe other Universes exist.

I still do not see how the concept of a DESCRIPTION of a world is converted into the WORLD itself.

It is not CONVERTED. It IS WORLD.

You know, there are some naïve questions like “what is space?”. People tend to ask such questions because of the intuitive conception that if something is not made of something then it is void and collapses. So the most satisfactory answer would be “space is made of spacions”. “Ah, yes, it makes sense”. Of course, after a while they would start wondering what spacions are made of.

We always had a situation that something was made of something: molecules of atoms, atoms of elementary particles, then came quarks, now we expect them to be made of strings. We so got used to it that we are not psychologically ready to the fact that in TOE that infinite reduction MUST END.

Say, you are looking at the page with few beautiful equations. These TOE equations describe, say, some function Q in some quaternion-valued space and some equations that function Q obeys. All other entities: time, space, gravity, particles, emerge from these equations.

But you start to worry. this is just an equation What makes it real, you ask yourself. You are desperately trying to find a magic wand which would touch the paper with formulas and the formulas will start to “live”. You are not satisfied with the fact that this IS TOE. If I would say that the reality is made of “realityons”, obeying these formulas, you will be satisfied, right? If I would say that there are JUST formulas, you will be not. You will be even satisfied if I would say that these formulas are emulated on some supercomputer. Because again it shows that there is smoothing behind the curtain – realityons, computers, or something.

Max Tegmark article is so shocking because he insists that there is nothing behind the curtain – no spoons, no realityons, no supercomputers. Fundamental notions are fundamental only if they do not consist of anything. Fundamental notions do not need any agents to be “incarnated”. Otherwise they are not fundamental and the theory is not a TOE.

The mathematical framework is eternal(B) and exists "forever"(Dmitry67 - wrong, because forever is (A) category). It does neither exist "in time(B)" nor "in space". But a universe can be created out of "something" and eventually it can fade away(A). Therefore the lifetime(A) of a universe could be finite(A), whereas the lifetime of the corresponding mathematical framework is certainly not(B) (homework: when will the prime numbers die?)

That logic is wrong. Time is a notion INSIDE our Universe. Other universes can have no time (euclidean space) or might have multidimensional time, or something else. Abstract world of Universes does not have time defines.

You are mixing 2 things:
(A)“eternal” as “lasting for eternity of time” = “being infinite in time”
(B) “eternal” as “existing independently of time” = “something to which a concept of time is not applicable”
In your quote I put marks (A) and (B) showing how you mix these notions. In the highlighted part you compare (A) and (B) which is incorrect.

RUTA

Sep3-09, 09:27 AM

You know, there are some naïve questions like “what is space?”. People tend to ask such questions because of the intuitive conception that if something is not made of something then it is void and collapses. So the most satisfactory answer would be “space is made of spacions”. “Ah, yes, it makes sense”. Of course, after a while they would start wondering what spacions are made of.

We always had a situation that something was made of something: molecules of atoms, atoms of elementary particles, then came quarks, now we expect them to be made of strings. We so got used to it that we are not psychologically ready to the fact that in TOE that infinite reduction MUST END.

We make exactly this point in the Conclusion of arXiv 0908.4348. Our answer is to put a self-consistency criterion at bottom, i.e., a mathematical co-definition of space, time and divergence-free sources (QFT parlance), that underwrites a discrete action for the path integral in the transition amplitude.

tom.stoer

Sep3-09, 04:12 PM

First of all I don't think that you responded to reason 2 and 3. Regarding Ockham's razor and reason 1 we should not waste too much time.

Some clarifications and remarks:

Each removal adds new information... contains MORE information than a list of ALL integers), so each removal must be justified.
I do not want to create selection rules by hand - I expect them to arise automatically. The idea regarding lifetime (see below) is one example.

It is not CONVERTED. It IS WORLD.
I do not mean "converted during a process", but "converted during our philosophical discourse". It's not the description that's converted into something but our understanding about the mathematical framework. So forget about this.

... there are some naïve questions like “what is space?”
That's not naive, that's a question which drives the whole scientific progress! w/o the question "what are atoms" we would not know anything about quantum mechanics.

... if something is not made of something ...
That's not my intention. I do not want to reduce the entities of the ToE to some more fundamental entity. This can happen, of course, but it's not required. In philosophy you can ask "what is goodness?" or "why does something exist instead of nothing?" or "what is time?" These questions do not automatically imply reductionism.

... he insists that there is nothing behind the curtain – no spoons, no realityons, no supercomputers. Fundamental notions are fundamental only if they do not consist of anything. Fundamental notions do not need any agents to be “incarnated”. Otherwise they are not fundamental and the theory is not a TOE.
But a mathematical framework consists of "something"; it consists of fundamental entities like an alphabet, definitions, rules and axioms. How do you "create" a mathematical framework out of nothing? You can only "create" it out of these constituents. But as I said above, that's not my basic concern here.

You are mixing 2 things:
(A)“eternal” as “lasting for eternity of time” = “being infinite in time”
(B) “eternal” as “existing independently of time” = “something to which a concept of time is not applicable”

Maybe I was not so accurate here, so I try again.

My basic intention is INDEED to mix these two "categories of existence", simple because the theory you are describing FORCES me to do this.

I start with my statement that each mathematical framework is eternal; there seems to be no meta-mathematics which "creates" or "kills" mathematics. So as mathematics has not been "created" at some "time", all mathematical frameworks are eternal, too.

The mathematical frameworks in question do not exist "in physical time" because time (and space) are entities "emerging" from these framework (not necessarily from all frameworks, as the ToE may allow for universes where physical time does not exist.

Up to now I do not mix these to "categories of existence". No my reasoning is as follows:

If some specific mathematical framework DESCRIBES a universe, the existence of the framework and the existence of the universe are two different "categories of existence"; therefore their "lifetimes" are independent. Whereas the description of the universe exists "before" the universe is "created" and after it "dies", the universe itself has a finite (physical) lifetime.

If a universe with finite "physical existence" IS IDENTICAL WITH the corresponding mathematical framework, you are in trouble. Either you have to forbid by some selection rule universes=frameworks with finite lifetime, or you have to lift the framework to some meta-level where its existence and "lifetimes" is again independent.

You are telling me that the universe and the framework are identical. So there must be a one-to-one correspondence of all entities, structures and aspects including EXISTENCE; especially you have to specify, what it means on the level of the framework that "the univeses dies" = "its existence comes to an end" = "the mathematical framework dies".
Either the existence of the framework comes to an end, too, then you have to explain what that means in pure mathematics, or the theory rules out universes with finite lifetime, or the framework does not die, but then its not identical to the universe in all aspects which contradicts your theory.
You have to explain how these sentences correspond to each other and how they can be formulated in a mathematically well-defined way.

Assume you are right and we are living in a universe=framework created by a big bang from nothing. What was the mode of existence of the framework before the big bang and how has it been created?

tom.stoer

Sep3-09, 04:48 PM

Not to forget - what do you think about my ideas:

... I would like add an idea how ToEs could be categorized:
- first requirement is that the ToE incorporates all known interactions in some way, e.g. as low-energy effective theories
- second requirement is that the ToE is a consistent mathematical framework, i.e. it must be mathematically well-defined
- third requirement is that the theory must post-dict at least some known facts like the standard model gauge symmetries, number of generations, number of space-time dimensions etc.
- forth requirement is that the theory must predict new phenomena which should be (at least in principle) falsifiable by experiment
A (meta) requirement) for a (meta) ToE is that the theory in question can at least support why she is the ToE. That means if the ToE contains a certain mathematical structure, there should be an explanation in terms of deeper structures or insights why this structure MUST be contained. This is subtle, of course. Example: if the ToE is grounded on local gauge symmetries, I would like to know WHY.

Dmitry67

Sep4-09, 04:36 AM

First of all I don't think that you responded to reason 2 and 3. Regarding Ockham's razor and reason 1 we should not waste too much time.

Reason 2: All discussions regarding the multiverse idea (many-worlds interpretation, landscape) I ever participated in came sooner or later to a point which I would describe like "I cannot explain why it's this way or that way - and therefore it's both ways!" That's not a sientific argument but an excuse only.

Reason 3 - and this is the most important one: even if you insist on the multiverse idea, it is by no means clear why ALL logically consistent ToEs should be physically real - why not only a certain subset? Compare it to evolution: not ALL possible species are alive, but only a certain subset. Why is this? Simply because there are selection rules (not hand made, but external to the species' ToE framework = the DNA, namely the environment) which suppress or constrain the evolution. In our case this could be some meta-theory, but nevertheless it must not be excluded.

No, it is exactly about the occams razor. Reason 2- I DID explain. The burden of proof is yours. Not I should explain why other universes exist, but you must proof that they don’t. See may explanation about justification of addition and removal. You can not agree with my reasoning, then lets discuss it. But your ‘Reason 2’ is just variation of Reason 1. The same for Reason 3 – again, it is variation of the same question, don’t you see? Yes, I insist that ALL Toes are physically real and there is no selection rule.

Dmitry67

Sep4-09, 04:50 AM

If a universe with finite "physical existence" IS IDENTICAL WITH the corresponding mathematical framework, you are in trouble. Either you have to forbid by some selection rule universes=frameworks with finite lifetime, or you have to lift the framework to some meta-level where its existence and "lifetimes" is again independent.

You are telling me that the universe and the framework are identical. So there must be a one-to-one correspondence of all entities, structures and aspects including EXISTENCE

I recommend you checking the concept of Block Time:
http://en.wikipedia.org/wiki/Eternalism_(philosophy_of_time)

Time does not "move". Universe is not a "movie". It does not "dies". "NOW" is just an illusion. Past is as real as future.

You are claiming that video tape turns to dust as soon as observers see "THE END" title, or Videogame self-destroys on your computer as soon as you go thru it to the very end.

Mathematical frameworkd is an analog of a program or a videotape.

If you have a universe which exists limited time (say from Big Bang to Big Rip) then the mathematical system describes it completely, from the very beginning, to the very end. it is a tape. You can look at it over and over. You can move at any direction.

As you know from SR, time is dimension (slightly special). Now replace time with space and repeat your reasoning. So, if universe is finite (limited volume) and say is only 100 meters long, the you say, I am in trouble, because my formulas dissapear to the left or to the right from the universe :)

Dmitry67

Sep4-09, 04:56 AM

Not to forget - what do you think about my ideas:

- first requirement is that the ToE incorporates all known interactions in some way, e.g. as low-energy effective theories
Agreed

- second requirement is that the ToE is a consistent mathematical framework, i.e. it must be mathematically well-defined
Definitely

- third requirement is that the theory must post-dict at least some known facts like the standard model gauge symmetries, number of generations, number of space-time dimensions etc.
Yes

- forth requirement is that the theory must predict new phenomena which should be (at least in principle) falsifiable by experiment
It would be good, but I am not sure.

A (meta) requirement) for a (meta) ToE is that the theory in question can at least support why she is the ToE. That means if the ToE contains a certain mathematical structure, there should be an explanation in terms of deeper structures or insights why this structure MUST be contained. This is subtle, of course. Example: if the ToE is grounded on local gauge symmetries, I would like to know WHY.
- Ha Ha.
I can not help you with it.
At first you violate occamz Razor and invent an unneeded notion - "selection rule"
They you ask: what properties does that rule have?
I dont have a selection rule, then I dont need to answer that question

tom.stoer

Sep4-09, 08:51 AM

No, it is exactly about the occams razor. Reason 2- I DID explain. The burden of proof is yours ...

Sorry, but that's demonstrably false!

We see, observe and live in exactly one universe. All other universes (frameworks, ToEs, ...) are speculations and not accessible experimentally. Therefore they are metaphysical ballast - as long as you cannot show that they MUST exist.

RUTA

Sep4-09, 09:01 AM

No, it is exactly about the occams razor. Reason 2- I DID explain. The burden of proof is yours. Not I should explain why other universes exist, but you must proof that they don’t. See may explanation about justification of addition and removal.

In general, the burden of proof is always on the positive claim. For example, if I claim ghosts exist, it's incumbent upon me to prove they exist, not you to prove they don't. If you claim QM entails multiple worlds, then that's something you must prove and in this case, since there are interpretations of QM without MW, the proof/evidence would have to be experimental.

tom.stoer

Sep4-09, 09:08 AM

Mathematical framework is an analog of a program or a videotape.

If you have a universe which exists limited time ..then the mathematical system describes it completely ... it is a tape.

You do not understand my point.

In my opinion there are two "categories of existence", a) the video tape and b) the movie (I do not have a problem with this point you view)

In our opinion these two categories have to be identified, the video tape (framework) and the movie (universe) are identical. But then you have to identify all aspects, entities and structures of the tape and the movie as well. If you can't do that, you failed to identify these concepts.

My impression is that you (partially) still refer to the framewortk as something that is external to the universe, something that is "only" its description. If you idea is right, then it provides not only a MAPPING between structures of the tape and structures of the movie, it provides an IDENTIFICATION.

Let me ask one easy question: do you think that the word "apple", the meaning of "apple" in the english language, the representation of an apple as picture, as "entity" on your retina / in your brain and as wiki article are identical? You do you think they are different aspects of one ontological nucleus?

tom.stoer

Sep4-09, 09:11 AM

Agreed ... Definitely ... Yes ... It would be good, but I am not sure.
Thanks!

Ha Ha.
Of course I expected this answer :-)
Are there other opninions as well?

tom.stoer

Sep4-09, 09:12 AM

... if I claim ghosts exist, it's incumbent upon me to prove they exist, not you to prove they don't...
Thanks!

Dmitry67

Sep4-09, 09:16 AM

In general, the burden of proof is always on the positive claim. For example, if I claim ghosts exist, it's incumbent upon me to prove they exist, not you to prove they don't. If you claim QM entails multiple worlds, then that's something you must prove and in this case, since there are interpretations of QM without MW, the proof/evidence would have to be experimental.

Yes, and the positive claim is in this case is "selection rule exists"
"Positive" is what is adding new information
Burden of proof is on the party which is adding new information

I copy what I said before, if you dont agree with the logic please tell me where:

Occams razor. In informational sense, “information should not be multiplied unnecessarily”. When we build something, we add building blocks, adding new information an every step. That is why every new stone you put in the building must be well justified. However, using this method you can add only finite number of stones/entities. You can’t define integers by providing a complete list, right?

When we manipulate with infinite numbers of entities we go in the opposite direction: we start from the Universum, and then remove something. Each removal adds new information (and list {12438, 59859599, 858585, 77} contains MORE information than a list of ALL integers), so each removal must be justified.

It seems you understand it and for that reason you call a “selection” rule (selection – taking one from many = removing others). Again, you are not asking how to justify the creation of OUR universe( that would be natural for one going from nothing to the Universum), you seek the justification of removal for the others. So we are on the same page.

But: if we go in the opposite direction, from the Universum, then any REMOVAL adds new information and hence is a subject of Occams razor. Going from nothing to the Universum we must justify any addition, going back we must justify any removal. You mentioned Occams razor and on the very next step started inventing NEW entity which you call a “selection rule”. Do you agree with my logic?

So Occams razor is the very reason I believe other Universes exist.

Dmitry67

Sep4-09, 09:19 AM

Sorry, but that's demonstrably false!

We see, observe and live in exactly one universe. All other universes (frameworks, ToEs, ...) are speculations and not accessible experimentally. Therefore they are metaphysical ballast - as long as you cannot show that they MUST exist.

Please also tell me where exactly you dont agree with my logic about the Occams razor (above)

tom.stoer

Sep4-09, 10:43 AM

I do not agree that the selection rule is the positive claim. My statement is that "other universes do exist" is the positive claim.

Maybe your proposal does not add information, but it adds an ONTOLOGICAL ENTITY for which you CLAIM existence w/o being able to PROVE existence. Either you can prove it experimentally or you have to demontrate it by other means. Otherwise these entities (universes) are metaphysical speculations.

RUTA

Sep4-09, 01:01 PM

Yes, and the positive claim is in this case is "selection rule exists"
"Positive" is what is adding new information
Burden of proof is on the party which is adding new information

I copy what I said before, if you dont agree with the logic please tell me where:

I'm talking about ontology, you're talking about methodology. Ontologically speaking, you're claiming MW so you need an experimental result consistent with MW and inconsistent with a single universe.

For example, suppose you start methodologically with "Everything imaginable exists." According to you, qualifiers such as "A thing must have empirical consequences" would be a negative, so that it is incumbent upon your skeptics to prove unicorns don't exist.

Dmitry67

Sep4-09, 01:43 PM

Lets talk about integer numbers.

Empty set, like a set of ALL integers is only one. It is, physically speaking, in the lowest entropy state.

Now I add a number, say, 34553. I add new information. There are mnay different lists which contain only one n umber, right? Interestingly enough, the set of all integers minus one number has the same property.

Now I add a second number, second entity. Now I have a combination of 2 numbers, and I have even more information. Adding more and more numbers to my list I add more and more information.

But this is true only if I add a finite number of integers. I can add an infinite number of integers, filling all voids, thus making my list a full list of integers. So adding an infinite number of integers I had reduced information!

So give an example,

{} - empty set - 0 bits.
{n} - one number - info about 1 number
{n,m} - 2 numbers - info about 2 numbers
...
{all except n,m} - info about 2 numbers
{all except n} - info about 1 number
{all integers} - universum - no info

I attract your attention to the fact that information at first increases and then decreases.

Maybe your proposal does not add information, but it adds an ONTOLOGICAL ENTITY for which you CLAIM existence w/o being able to PROVE existence.

No. I dont add AN ENTITY. If I would be adding ONE entity you would be absolutely right.

I am adding an infinite number of entities to a list with one element (only our universe). The list I add in complementary to that list and union becomes a Universum - a list of all possible universes.

Hence I decrease an information, and occams razor is on MY side.

RUTA

Sep4-09, 02:15 PM

Lets talk about integer numbers.

So give an example,

{} - empty set - 0 bits.
{n} - one number - info about 1 number
{n,m} - 2 numbers - info about 2 numbers
...
{all except n,m} - info about 2 numbers
{all except n} - info about 1 number
{all integers} - universum - no info

I attract your attention to the fact that information at first increases and then decreases.

This has nothing to do my claim about methodology and ontology, but I believe your claim is false. In fact, I would argue that the set of all integers contains an infinite amount of information. To make my point, produce the set -- not the words "all integers" but the elements themselves.

Dmitry67

Sep4-09, 03:00 PM

"You are wrong"
These 13 characters gives you some information.
Now I provide you a list of all 26**13 combinations of characters. Beginning from AAAAAAAAAAAAA to ZZZZZZZZZZZZZ. Somewhere in the middle you will find "YOU ARE WRONG" and "YOU ARE RIGHT". What information you have now? Nothing!

And asking me to write all integers... Science would end if we stop at the level of "2 apples plus 3 apples makes 5 apples". How do we suppose to work with infinite sets if we need to write all the elements???

RUTA

Sep4-09, 03:38 PM

And asking me to write all integers... Science would end if we stop at the level of "2 apples plus 3 apples makes 5 apples". How do we suppose to work with infinite sets if we need to write all the elements???

This has nothing to do with the progress of science, we're talking about how much information is contained in the set of all integers. I say it's infinite and you say it's zero. To argue my point, all I have to do is "play dumb" and require you to give me the information explicitly, i.e., list the elements of the set. If you're correct, you have nothing to send me. If I'm correct, you have an infinite number of numbers to send me. That's my argument.

How does this bear on the original post for this thread? I've lost track.

tom.stoer

Sep5-09, 11:03 AM

... and occams razor is on MY side.
No it isn't.

From a ontological point of view we can be sure that one universe exists; everything else is speculation.

From a computational-complexity point of view there is no difference between the two statements
a) one universe exists
or
b) all possible universes exist - except one
Of course specifying the one in both cases should require the same amount of information.

Similarly computationally the statements
a') no universe exists
and
b') all possible universes exist
have the same complexity.

If you argue strictly based on computational complexity and with Ockams razor, then you cannot distinguish between a') and b') nor can you distinguish between a) or b). So in order to do that you have to refer to some experimental result, i.e you have to enlarge your reasoning beyond computational complexity.

You do that by taking into account "known facts" and by going from a mathematical to an ontological reasoning. Of course you can rule out a') immediately. You can trust in a least one universe which means that ontologically and based on Ockams razor you should not add more assumptions than strictly necessary. So you add the assumption that one universe exists and - wow - it agrees with the known facts. If you would instead add an uncountable set of universes it would still agree with the known facts, but you have to explain why "they are there but invisible". Therefore you add assumptions which you cannot prove.

And don't forget: you cannot use your "mathematical multiverse hypothesis" as starting point for your proof as your quest is just to prove exactly this "mathematical multiverse hypothesis".

Vanadium 50

Sep5-09, 12:28 PM

If you have a link handy to some particular abstract from the conference you were talking about, I'd be glad to give a look.

Sorry - it wasn't exactly handy. See JD Hague's talk (http://www.auger.org/technical_info/ICRC2009/arxiv_astrophysics.pdf) for the Auger view: "The evidence for anisotropy has not strengthened since the analysis reported in [1]. The degree of correlation with objects in the VCV catalog appears to be weaker than suggested by the earliest data."

As you know, HiRes sees no such correlation.

Nature's In the Field (http://blogs.nature.com/news/blog/2009/05/aps_2009_pierre_auger_backs_of.html) says "And now, today, Stefan Westerhoff, an Auger scientist from the University of Wisconsin at Madison, said that, based on new particle detections -- they have more than 50 now -- the correlation no longer holds. "The signal strength is certainly considerably weaker now," he told his audience. "This is certainly a disappointment."

The proceedings of that conference (APS 2009) unfortunately seem not to be available yet.

marcus

Sep5-09, 02:08 PM

Fantastic!
this makes UHECR more of a mystery.
Maybe we should have a separate thread to keep track of this, but for now I will continue in context. Here is more of the 3 May quote about the Auger news at APS meeting:

==quote Nature.com==
APS 2009: Pierre Auger backs off claims for cosmic ray source

The mysterious origin of ultra-high energy cosmic rays is, it seems, still a mystery. Two years ago, scientists at the Pierre Auger Observatory in Argentina thought they had it solved. They published a paper in Science, based on two dozen particles, that there was a correlation with the location of Active Galactic Nuclei -- supermassive black holes that accelerate jets of material at near-light speed throughout the universe. At the time of the announcment, there was some doubt: The Hi-Res project, which scans the northern sky like Auger does the south, found no such correlation.
And now, today, Stefan Westerhoff, an Auger scientist from the University of Wisconsin at Madison, said that, based on new particle detections -- they have more than 50 now -- the correlation no longer holds. "The signal strength is certainly considerably weaker now," he told his audience. "This is certainly a disappointment."
But the correlation isn't so weak that they can give up. The 70% correlation between the cosmic rays and the AGN at the time of the Science publication has now dropped to about 40% -- considerably less, but not enough to support the null hypothesis. What could cause some particles to come from AGN, but not others? Westerhoff says it might have something to do with their composition. Maybe the protons come from the AGN, whereas higher mass cosmic rays, say iron nuclei, do not...
==endquote==

Here's a link to my post #66
http://physicsforums.com/showthread.php?p=2330554#post2330554
which had the abstract of an April 2009 paper by Glennys Farrar et al. They seemed to think there was some correlation too, but not complete.

Vanadium 50

Sep5-09, 02:43 PM

The thing that's not being said is that if you split the data into the "early" and "late" phases, the correlation is almost entirely in the early set. You can sort of see it yourself - if with half the data you have a 70% correlation, and with two halves it's 40%, what's the correlation in the second half?

tom.stoer

Sep5-09, 05:25 PM

How does this bear on the original post for this thread? I've lost track.

I think I started the trouble in post #17 saying that ... the LHC will be absolutely mute about any "ToE". It can support theories with respect to their low energy regime, but nothing else.

Then we started to discuss what a ToE could be, what the requirements are etc.

If we agree that a good candidate for a ToE must incorporate all known interactions, must be predictive up to arbitrary high energies and must be mathematically consistent (e.g. free of singularities, non-renormalizability, certain anomalies, ...) - and if we forget about all metaphysical speculations - then it's time to remember that we currently do not know a single candidate ToE.

RUTA

Sep6-09, 10:31 AM

I think I started the trouble in post #17 saying that ... the LHC will be absolutely mute about any "ToE". It can support theories with respect to their low energy regime, but nothing else.

Then we started to discuss what a ToE could be, what the requirements are etc.

If we agree that a good candidate for a ToE must incorporate all known interactions, must be predictive up to arbitrary high energies and must be mathematically consistent (e.g. free of singularities, non-renormalizability, certain anomalies, ...) - and if we forget about all metaphysical speculations - then it's time to remember that we currently do not know a single candidate ToE.

Thanks. I can't think of a theory or pseudo-theory (e.g., strings) that meets your requirements for a candidate ToE. And, I agree that any such theory would not be confirmed by low energy tests alone, unless that is the realm where it is deemed fundamental. One really has to produce definitive experimental confirmation of its most fundamental aspects and the fundamental realm of all ToE-wanna-be programs today resides at high energy (I think strings would require an accelerator as big as the galaxy, and GUTs an accelerator as big as the solar system). Do you know of any exceptions, i.e., any programs where unification doesn't involve high energy realms? I asked this question before (maybe on this thread) and no one responded with any.

tom.stoer

Sep6-09, 03:19 PM

I can't think of a theory ... that meets your requirements for a candidate ToE. ... Do you know of any exceptions, i.e., any programs where unification doesn't involve high energy realms? I asked this question before (maybe on this thread) and no one responded with any.

I am not sure but I think I remeber. I didn't respond because unfortunately I do not have anything to say about it. I do not know any candidate ToE.

Remark: should we have a look at strings and why they fail to be a candidate ToE?

friend

Sep6-09, 05:50 PM

I am not sure but I think I remeber. I didn't respond because unfortunately I do not have anything to say about it. I do not know any candidate ToE.

Then perhaps we should start from principle alone to develop a TOE. It doesn't seem likely that we will ever be able to generate the energies necessary to confirm a TOE that is derived from curve fitting the data from experiment; we can't experiment with other possible universes. So we have no choice but to try to rely on some overriding, underpinning principle. But what principle could explain absolutely everything? The only thing that could explain absolutely everything is logic. Otherwise, you are left with something in nature, particles, strings, or spacetime structures, that need further explanation... Where did those things come from? But all explanations stop and you have a TOE if physics is derived from logic itself. So I wonder how the theoretical physics community looks upon any attempt to derive physics from logic. Do they dismiss such attempts out of hand? Are they skeptical and wait to see the theory? Would they gladdy welcome such a derivation if one were presented?

Fra

Sep6-09, 06:01 PM

So I wonder how the theoretical physics community looks upon any attempt to derive physics from logic. Do they dismiss such attempts out of hand? Are they skeptical and wait to see the theory? Would they gladdy welcome such a derivation if one were presented?

How would you derive physics from logic? If we consider a pure axiomatic approach to physics from which things are deduced, then the question is WHAT axioms? Then it becomes the question of finding axioms. It doesn't solve anything in itself. It just moves the problem around. Then the status of the axioms is the same as the status of physical law.

If you then, like I do, think it's best to see laws as evolved, and evolving, then the same would apply to axiomatic approaches. The set of axioms would be subject to constant negotation and thus in principle, evovling, and there would not exists a universal timeless objective measure of the validity of axioms. They could be judged exlusively by their fitness only.

In this latter sense, I think physics could be done that way, but in this dynamical axiom vision, the problems are the same, it's just that we relabeled the words. Law -> axiom. Without solving any of the core issues.

/Fredrik

Fra

Sep7-09, 12:48 AM

we will ever be able to generate the energies necessary to confirm a TOE that is derived from curve fitting the data from experiment; we can't experiment with other possible universes. So we have no choice but to try to rely on some overriding, underpinning principle. But what principle could explain absolutely everything?

I thought about this again, and in specific sense I think this might be an idea. As I see it, scientific process has two components it's

1) the production and construction of inferences, and there appears to be a kind of logic to this.
2) the feedback from the environment (~experiment)

A complete picture can not grow without (2) I think, but otoh I think we have not even close to exhauset the power of (1). I also think it's an almost exaggerated interest in the high energy experiments as the only place to get things. Some others point to cosmology, but I would like to add another more obvious and more accesible scale, which is the complex system physics, which would have to deal/explain behaviour that emerge only in complex systems.

Ariel Caticha going the tradition of Jaynes attempts to derive the laws of physics from general principles of inferece, such as rationality and honesty. This might partially be said to be in this direction.

You asked for "physics from logic", and Ariel, Jaynes and those working in that tradition view probability theory as an "extension to logic".
But while his idea is to derive the laws of physics from more or less standard probability and an Max Ent principle for information processing. I think one can go one level deeper and ask if standard probability and maximal entropy are really the only rational premises? I think here is alot one can do without high energy accelerators.

And maybe this can ultimately produce more specific and more confident predictions for future high energy experiments or astronomical observations.

About my objection to the axiomatic approach - this is actually also what Ariel is doing and is where I disagree with them, since he is starting with some key axioms that leads to a unique formalism (which is of course probability theory, and it's no coincidence) and a unique rule for information entropic processing by a specific choice of entropy measure.

How about if we instead consider that the axioms are say mutating, could different systems of inference, in some situations be more fit? I think so. This is as far as I konw very poorly investigated. And to investigate this, one does not at least immediately need any LHC data. So I think there is alot of progress that could be done still on point (1)

/Fredrik

Dmitry67

Sep7-09, 01:23 AM

This has nothing to do with the progress of science, we're talking about how much information is contained in the set of all integers. I say it's infinite and you say it's zero. To argue my point, all I have to do is "play dumb" and require you to give me the information explicitly, i.e., list the elements of the set. If you're correct, you have nothing to send me. If I'm correct, you have an infinite number of numbers to send me. That's my argument.

How does this bear on the original post for this thread? I've lost track.

ok. Alice sends Bob 2 messages:
* first contains the length of a list
* second message contining a list.

For example:
* 3
* {39449, 545959, 6969}

As information can not travel faster then light, Bob has to wait the arrival of the second message until he is able to reproduce a list.

Except: except 0 and inf. Receiving "inf" Bob already knows what Alice is going to send him. Hence, inf and 0 does not contain any information.

Dmitry67

Sep7-09, 01:35 AM

From a computational-complexity point of view there is no difference between the two statements
a) one universe exists
or
b) all possible universes exist - except one
Of course specifying the one in both cases should require the same amount of information.

Similarly computationally the statements
a') no universe exists
and
b') all possible universes exist
have the same complexity.

If you argue strictly based on computational complexity and with Ockams razor, then you cannot distinguish between a') and b') nor can you distinguish between a) or b). So in order to do that you have to refer to some experimental result, i.e you have to enlarge your reasoning beyond computational complexity.

You do that by taking into account "known facts" and by going from a mathematical to an ontological reasoning. Of course you can rule out a') immediately. You can trust in a least one universe which means that ontologically and based on Ockams razor you should not add more assumptions than strictly necessary. So you add the assumption that one universe exists and - wow - it agrees with the known facts. If you would instead add an uncountable set of universes it would still agree with the known facts, but you have to explain why "they are there but invisible". Therefore you add assumptions which you cannot prove.

And don't forget: you cannot use your "mathematical multiverse hypothesis" as starting point for your proof as your quest is just to prove exactly this "mathematical multiverse hypothesis".

We have almost agreed :)

Yes, empty set and universum contain the same amount of information - ZERO
So our multiverse contains NO information (of course not for "frogs") as it is Universum and it always exists in one and only one possible state.

And yes, my reasoning is:
2 possible options: NOTHING or EVERYTHING, we observe SOMETHING, hence the second option is valid. Note that "assumption that one universe exists" is not an assumption - it is an experimental fact :)

Your last point is valid: I use MUH as an axiom, because I dont see any choice.

I have 2 questions if you have time:
1. Do the inner regions of black holes (inside their horizons) exist? Are any claims of what is going on there falsifable?
2. Do you think that TOE would use only formulas or it would need to use some words? In another words, do you expect TOE to be interpretation-less? What do you expect TOE to do with the interpretations? (give a new one, tell us what is a right one, making the whole notion of interpretation a nonsense)?

tom.stoer

Sep7-09, 11:13 AM

1. Do the inner regions of black holes (inside their horizons) exist? Are any claims of what is going on there falsifable?
Yes, inner regions do exist and in principle they are accessible for an experiment.

Think about a brave colleague (an expert in theory, experiments and results regarding GR and QG). His last project (together with his students) is to travel into a gigantic black hole and to spend the rest of his life in order to complete the knowledge regarding black holes. Within this large black hole he will - besides his experimental activity - publish research papers, create an own arxiv repository, organize conferences etc. Of course he has to hurry up, but in principle nothing will be in conflict with his objective.

2. Do you think that TOE would use only formulas or it would need to use some words? In another words, do you expect TOE to be interpretation-less? What do you expect TOE to do with the interpretations? (give a new one, tell us what is a right one, making the whole notion of interpretation a nonsense)?
I am not so sure.

A short-term candidate will certainly not be free of interpretation and non-mathematical rules ("if X ... then apply rule Y"). Even the basics of that theory may be easier to formulate in english language ("the speed of light is constant in all reference frames").

A long-term candidate may exist on the "next stage"; it could be some kind of meta-theory that addresses these formalization-issues; but perhaps it will aim for something totally different - today we do not know.

I expect that a candidate ToE will be based on few (hopefully :-) mathematical and non-mathematical "axioms". It will be able to address questkions like:
- what is the structure of space-time
- how does space-time, local gauge-symmetry, ... arise from X (where X is a more fundamental structure)
- why do we live in 3+1 dimensions
- why do we observe U(1)*SU(2)*SU(3)
- why do we observe three fermion generations, ...
- what is the origin of the cosmological constant
- what replaces the black hole and big banhg singularity, ...
- ...

After we are able to study one candidate ToE, of course new questions will arise, especially regarding the mathematicsl structure(s) X. Perhaps there will be competing structures X, X', ... (strings, loops, non-commutative geometry, ...). I do not know if this will be an iterative process (just as it was the last centuries) or if there will eventually be a paradigm shift which allowes us to go the meta-theory level.

I agree that we need some deeper insights regarding development of physical theories, especially as we will have less new experimental facts - just because of the required energy scale. That means we must focus more on abstract ideas, mathematical justifications, completeness, consistency etc.

As you say, something like MUH will be an axiom (you could even say dogma, doctrine) and will therefore belong to / be related to the philosophical realm. I am pretty sure that physics and philosophy will again come closer together has they are today (there was an intensive dialog in the early twenties when QM was developed; in the following decades "shut up and calculate" became the major guideline.

Dmitry67

Sep7-09, 02:41 PM

1 I expect that a candidate ToE will be based on few (hopefully :-) mathematical and non-mathematical "axioms".

2
- why do we live in 3+1 dimensions
- why do we observe U(1)*SU(2)*SU(3)
- why do we observe three fermion generations, ...

1 I always asked - but never got an answer - for an example of a "non-mathematical" axiom. An example of an axiom which can not be expressed in mathematical terms. Could you provide any examples (even not realistic, not about our universe)?

2 What kind of "why" do you mean?
a. anthropological principle
b. cosmic darwinism
c. proof of mathematical inconsistency of other possible universes

tom.stoer

Sep7-09, 03:17 PM

Regarding a non-mathematical axiom: take constant c in GR as an example: as long as you do not have the full developed GR based on manifolds it's hard to write this as a mathematical axiom; of course you can start with a local description which will eventually correspond to the tangent space, but you don't know this in advance. So take this as a an example.

Regarding "why": the basic problem is that it's easy to ask these why-questions, but it's hard to answer them; therefore I don't think that it's a good idea to exclude ideas at this early stage. So right now I am trying to be open-minded to all three directions. My problem with
a) is that it appears to me as self-immunization against falsification
b) is that it sounds nice but nobody can tell me how evolution, mutation and evolutionary pressure could work; what is the DNA of the physical laws?

Of course I cannot prove that other universes do not exist; nevertheless I would take c) as starting point and search for
i) a theory that describes this specific universe and
ii) a selection principle (could be consistency or something else)
[this would be MY research program - I don't want to force anybody to abandon other lines of research]

tom.stoer

Sep7-09, 03:32 PM

@friend & fra: I think you are trying to do something like "finding the DNA for physical law".

I have no idea how I would start and I am not familiar with the ideas and research programs you are mentioning. However, it becomes clear that even if you want to avoid axioms and rules but try to let physical laws emerge from something "deeper", you need a set of rules. Logic is perhaps the simplest mathematical structure, but I am afraid that logic alone will do the job. And negotiation must follow some logic, too. So it's at least logic that serves as a basis for you.

One remark: I am still not sure if we all understand what Tegmark wants to say. What does the small word "IS" mean? Is it absolute identity, not only isomorphism? Are the U(1) and the SUO(2) identical - or just isomorphic? Do they become strictly identical if I remove all "human baggage"? Is it correct, sufficient and reasonable to assume that there IS NOTHING ELSE but a relation between mathematical entities? He is not very explicit when it comes to relations to different philosophical schools ...

Fra

Sep7-09, 05:41 PM

So it's at least logic that serves as a basis for you.

Sure, of course I kind of rely on some kind of logic in the general sense, but I thought that from the context the association to logic here was to ideas that mathematical consistency and deductive logic. Ie. that you can get to KNOW the certain laws by though along - no interaction. I beg to differ with that view.

The kind of logic I do rely on is loosely speaking inductive logic, not deductive logic. Clearly the traditional quantification of inductive reasoning is probability theory. Ariel and Jaynes makes this point strong. However, even the rules of inference themselves are not unique. Here I differ with them.

They formalise inductive reasoning, into probability theory and then use various bayesian or max entropy methods as the RULES of inference. But of course, the rule of inference is chosen and the isntant you choose the specific entropy measure. Similarly there are objections to bayes rule.

I am trying to generalise inductive reasoning, by suggesting that by taking the proper intrinsic view, other rules of inference other than bayesian and max ent method are possible, and bayesian and max end methods with a fixed entropy measure are NOT the optimal inferences. Sometimes they are of course, but it's not a general case.

I have hopes that quantum logic to mention one think should b4e satisfactory explain as a unique choice of optimal inference RULE in particular situations! But again, but understanding hte general case, I also expect to understand the generalisation of Quantum logic, which will help solve QG problems and unification.

So in a certain sense, I am looking for a mathematical reconstruction, but it is not possible to understand the motivation from a pure mathematical perspective. Also the ides suggested does contain self-referential elements, and the this self-interaction should amount to a kind of self-inference, a kind of self evolution.

I think a correspondence here in simple case would be that the schrödinger equation is really just the expected self-evolution, or the self-inference. The optimal inference when external feedback is taken into account is the collapse thing.

In this view there is as I see it no mystery with the collapse at all.

Given that I want to take this further than Ariel and Jayes, who basically reconstructs the same old continuum probability theory and use that as a basis for inference, one of my basic conjecture, is like theirs that the laws of physics ARE more or less the rules of rational inference. And the point is then tht the optimal inference is a matter of point of view, since the instrinsic view allows no external measures of optimality.

There are also the symmetry principles hidden here, symmetries are emergent as a result of interactions, and are not fundamental. Understanding the interactions here should in my expecation help explain why certain symmetries in the rules of rational inference are selected. And thus the symmetries of physical law.

I have understood that this is hard to convey. Having thought of this now for a new years I think the conceptual part is becoming pretty clear, but still I see that not many seem to connect, with a few exceptions. Probably because I do not know of any current papers that does exactly this. The related ideas are from smolins, evolving law, ariel caticha and ET jaynes, as well as some other. Olaf Dreyer has partly acknowledge the inside view.

I suppsed this will remain foggy until substantial progress is made.

Edit: I also associate time evolution with the inference processes. The relativity of time in relativity should be reproduced from the relativity of inference, as in the emergent symmetries. Note that both Jaynes and Olaf Dreyer belives that GR could be DERIVED from the proper reconstruction. I fully share this view, although I have a different view of the starting points. Instead of derive, I prefer to say emergent, and this emergence is a physical equilibration process.

/Fredrik

Fra

Sep7-09, 06:02 PM

Obvious this talk about optimal inference and selection for inference rules, what is the assumption on the seleciton?

My conjecture is that the selection is the obvious one - rules that are destructive are disfavoured and those that are self-preserving and constructive (that grow more competitive) are selected for.

So the inference rule is the DNA of physical law IMO. But the DNa can not be fudnamental, clearly the DNA itself must have evolved as well. Thus I more think of different levels of this code.

So the rules of inference that are selcted in our universe and those that are optimally self-preserving. Ie. the game preserves itself.

I'm trying to model this by pondering how to construct optimal measures, that are basis for actions, given limited resources.

My starting point is the low end of the complexity scale, becuase here the options are finite, and then ponder what structure emergenes as the resources are scaled up. During this journey spacetime and it's symmetries should follow - I hope.

/Fredrik

tom.stoer

Sep8-09, 12:56 AM

Dmitry67

Sep8-09, 02:20 AM

Regarding a non-mathematical axiom: take constant c in GR as an example: as long as you do not have the full developed GR based on manifolds it's hard to write this as a mathematical axiom; of course you can start with a local description which will eventually correspond to the tangent space, but you don't know this in advance. So take this as a an example.

Could you clarify?

c=1

so I dont see any problems with it. However, it reminds me about the question I wanted to ask about the parameters of the Standard Model. How do you expect the axctual values be explained by the TOE?

Say, Mass of Up Quark / Mass of Down Quark?

1. Some analytical expression (even very complicated) derived from TOE, say Mu/Md = sin(ln(2*pi) / sqrt(e))

2. It is just a parameter. It is an axiom. (possible justification using AP)

3. It is a parameter but it can vary (cosmic darwinisim, or alternatively superstiring theory with bulk, colliding branes giving birth to the universes with all possible combination of parameters, then AP)

Dmitry67

Sep8-09, 02:26 AM

One remark: I am still not sure if we all understand what Tegmark wants to say. What does the small word "IS" mean? Is it absolute identity, not only isomorphism? Are the U(1) and the SUO(2) identical - or just isomorphic? Do they become strictly identical if I remove all "human baggage"? Is it correct, sufficient and reasonable to assume that there IS NOTHING ELSE but a relation between mathematical entities? He is not very explicit when it comes to relations to different philosophical schools ...

Let me quote him (chapter Description versus equivalence)

Whereas the customary terminology in physics textbooks is that the external reality is described by mathematics, the MUH states that it is mathematics (more specifically, a mathematical structure). This corresponds to the “ontic” version of universal structural realism in the philosophical terminology of [14, 22]. If a future physics textbook contains
the TOE, then its equations are the complete description of the mathematical structure that is the external physical reality. We write is rather than corresponds to here, because if two structures are isomorphic, then there is no meaningful sense in which they are not one and the same [19]. From the definition of a mathematical structure (see Appendix A), it follows that if there is an isomorphism between a mathematical structure and another structure (a one-to-one correspondence between the two that respects the relations), then they are one and the same. If our external physical reality is isomorphic to a mathematical structure, it therefore fits the definition of being a mathematical structure.

If one rejects the ERH, one could argue that our universe is somehow made of stuff perfectly described by a mathematical structure, but which also has other properties
that are not described by it, and cannot be described in an abstract baggage-free way. This viewpoint, corresponding to the “epistemic” version of universal structural
realism in the philosophical terminology of [14, 22], would make Karl Popper turn in his grave, since those additional bells and whistles that make the universe nonmathematical by definition have no observable effects whatsoever.

I 100% agree and have nothing to add.

tom.stoer

Sep8-09, 03:53 AM

Could you clarify?

c=1
you have to embed this statement in a context which you call "baggage". w/o context c=1 is meaningless; therefore you have to define the context mathematically as well. But no you have the problem that you
either have to specify (via an axiom) that spacetime is a 4-dim pseudo-Riemann manifold (but this is certainly not a nice and easy-to-beliece axiom)
or you have to find simpler axioms for which a formal definition makes sense.

Einstein had the c=1 "axiom" in mind but derived the context (pseudo-Riemann manifold) later. That's why I still think that it's a good example, at least for GR (possibly not for the ultimate theory).

How do you expect the axctual values be explained by the TOE?

Say, Mass of Up Quark / Mass of Down Quark?

1. Some analytical expression (even very complicated) derived from TOE, say Mu/Md = sin(ln(2*pi) / sqrt(e))

2. It is just a parameter. It is an axiom. (possible justification using AP)

3. It is a parameter but it can vary (cosmic darwinisim, or alternatively superstiring theory with bulk, colliding branes giving birth to the universes with all possible combination of parameters, then AP)
I don't know; the ToE must deliver both the value and the way how and why this value is produced:-)

1. I guess it will not be an analytical expression, but of course it could be the (implicit) solution of an explicit equation.

2. no!

3. Could be, but then I would prefer an answer why it's this value or at least some range. If somebody claims a kind of evolutionary process then she/he must specify the rules regarding evolutionary pressure, selection, spawning of baby-universes, cosmic DNA and all that.

Compare it to evolution in biology: Darwin had a couple of ideas (e.g. "survival of the fittest") and some mechanisms for selection (population, predators, ...). In the meantime we were able to figure out the rules for the DNA (at least partially).

I would expect something similar for a ToE claiming that a specific theory (or parameter set) emerges from an underlying structure (multiverse or whatever). What I have seen is that nobody was able to answer these questions so far. In string theory nobody is able to construct M-Theory, nor has anybody developed a clear idea what the mathematical structure of the landscape is, nor is there some kind of measure on the multiverse (you need a measure to count the population ...), nor do I see a clear prediction regarding spawning of baby universes etc.. There are some nice ideas, but sooner or later people start to wave their hands and cry for the anthropic principle.

The whole discussion did not start because of a clear fundamental principle but only because people where not able to do the calculations!

tom.stoer

Sep8-09, 04:05 AM

Let me quote him (chapter Description versus equivalence) ... I 100% agree and have nothing to add.
OK, I got the point (missed it when I was reading the paper).

So he says that iff two entities are isomorphic to 100% and in all their aspects and properties, then they are identical. Therefore iff the universe can be described in pure mathematical language w/o any baggage, then the universe IS this mathematical structure - and the mathematical structure IS the universe.

I agree that from a purely mathematical point of view this is sound!

Of course it's misleading to discuss the simulation approach, as this approach explicitly introduces a meta-level to the simulation (the program plus its output), namely the simulation engine (HW, operating system, ...). The paper could very well live w/o these remarks.

Dmitry67

Sep8-09, 05:46 AM

Of course it's misleading to discuss the simulation approach, as this approach explicitly introduces a meta-level to the simulation (the program plus its output), namely the simulation engine (HW, operating system, ...). The paper could very well live w/o these remarks.

Well, he actually denies that it makes sense to talk about the simulation:
check pages 18-21

Dmitry67

Sep8-09, 05:50 AM

you have to embed this statement in a context which you call "baggage". w/o context c=1 is meaningless; therefore you have to define the context mathematically as well. But no you have the problem that you
either have to specify (via an axiom) that spacetime is a 4-dim pseudo-Riemann manifold (but this is certainly not a nice and easy-to-beliece axiom)
or you have to find simpler axioms for which a formal definition makes sense.

Einstein had the c=1 "axiom" in mind but derived the context (pseudo-Riemann manifold) later. That's why I still think that it's a good example, at least for GR (possibly not for the ultimate theory).

In SR and GR there is no 'c' if you work in Planks units.
"c" is a thing invented by humans, it does not have any fundamental meaning.

Like people used degrees to measure angles. But in mathematics it is more natural to use radians. So conversion constant for conversion from grads into radians does not have any fundamental meaning.

But again, any claims that c=1, x=3, space has 4 (10,11,26) dimensions can be encoded in a pure mathematical language. That is why the idea of Max Tegmark is so solid: I had never seen anything that could qualify as "physical" axiom. Something when can not be expressed - in principle !!! - in mathematical language.

The only candidate is Smolin's "evolving law". It is pure handwaving without a single formula :) Sorry Fra

tom.stoer

Sep8-09, 07:22 AM

In SR and GR there is no 'c' if you work in Planks units ... "c" is a thing invented by humans, it does not have any fundamental meaning.
Really?

"c" has two meanings:
- it is a fundamental constant with the unit "m/sec"; this is somehow invented by us humans
- it is the speed of light (or better: propagation of signals); this is a result of the theory

It is interesting that even in GR locally the light cone = propagation of signals respects "c=1". That's not trivial but emerges from the theory.

Compare it to mass. You can argue that with "Planckmass=1" the meaning of mass dissapears. Still, GR is based on the assumption - and it reproduces this assumption - that inertial and gravitational mass are equal. This is non-trivial and emerges from the theory (I think it is not understood to 100% as GR does not always allow for an unabmiguous definition of mass).

Therefore I think that these two examples serve as non-mathematical axioms.

Dmitry67

Sep8-09, 07:48 AM

Really?
1
- it is the speed of light (or better: propagation of signals); this is a result of the theory

2
It is interesting that even in GR locally the light cone = propagation of signals respects "c=1". That's not trivial but emerges from the theory.

3
Compare it to mass. You can argue that with "Planckmass=1" the meaning of mass dissapears. Still, GR is based on the assumption - and it reproduces this assumption - that inertial and gravitational mass are equal.

1 if it is a RESULT of a theory then it is NOT an axiom!
2 same
3 Well, GR is not a final theory. In TOE mass is a tricky thing (HUP, virtual particles, Unruh effects-accelerated frames etc). So that equivalence should emerge from TOE as a result. Note that in QM equivalence principle does not work on short timescales (because time and mass do not commute) - another proof that that principle is not fundamental.
But even if we forget it we can still write Mg=Mi :)

Sorry, I dont see any physical axioms.

Fra

Sep8-09, 08:38 AM

You have to define how a rule looks (or a law or whatever) like, and you have to define how the negotiation between rules (which are mathematical entities) looks like.

Can you explain how this approach could look like mathematically?

What are your symbols, relations, axioms etc.? How does a rule look like?

You have to define how "rules act on rules": you have a negotiation process for which you need rules; "rules acting on rules" can therefore be negotiation between physical laws, but it can also be the evolution of some physical entity.

How and when do which rules interact? How are two (or three? four?) interacting rules selected? How do they "come together"? How does the DNA look like? How does mutuation, crossing-over and spawning of new rules look like?

How do you count rules or members of classes of rules in order to decide which rules are successfull = dominant?

What will our universum be? One master rule or a colletction of the most successfull rules?

Don't you need a meta-rule which "initiates" this whole process - which then becomes part of it and is subject to negotiation as well? what are your initial conditions?

I think I've possibly got the swine flue or something and I feel a bit lame and fevery today. I'm supposed to go on a business trip on thursday so I'm hoping to rest and get rid of the fever before that.

I'l try to comment more later.

I've never tried to seriously present much of the specifics here for several reasons.

- As I understand you're not allowed to post personal research, except possibly in the indepdendnt research section.

- There is soo much left to do, that I consider it my own problem to sort it out. This is work in progress but I'm an amateur and progress is slow on hobby basis.

This is why I mainly try to *discuss* things at just an intellectually sound and conceptual level, which is within the guidelines as I understand. Another reason for this is that this is the motivation also for my CHOICE of mathematics.

I'll try to give you a some more hints later.

/Fredrik

tom.stoer

Sep8-09, 08:54 AM

Sorry, I dont see any physical axioms.
They are there - directly in front of your eyes.

The weak equivalence principle = the universality of free fall = the equality of inertial and gravitational mass is a physical, non-mathematical axiom of GR. It has been formulated w/o a mathematical framework. Einstein then derived this framework = GR from which this principle (as a law) did emerge. The equation Mg=Mi as a starting point is mathematically nice but physically meaningless w/o specification of the framework.

tom.stoer

Sep8-09, 08:57 AM

... so I'm hoping to rest and get rid of the fever before that.
Get well soon!!!

There is soo much left to do, that I consider it my own problem to sort it out. This is work in progress but I'm an amateur and progress is slow on hobby basis.
I fully understand your situation as mine is similar :-)

Thomas

Dmitry67

Sep8-09, 10:34 AM

They are there - directly in front of your eyes.

The weak equivalence principle = the universality of free fall = the equality of inertial and gravitational mass is a physical, non-mathematical axiom of GR. It has been formulated w/o a mathematical framework. Einstein then derived this framework = GR from which this principle (as a law) did emerge. The equation Mg=Mi as a starting point is mathematically nice but physically meaningless w/o specification of the framework.

no and no.

Equivalence principle, mach's principles etc were just a MOTIVATION to create a theory. It is cristally clear if we take SR:

2 axioms (in fact, observational fact) -> einsteins version of SR -> deeper understanding of spacetime (Minkovsky) -> 2 'axioms' now are derived from the formalism.

Lets return to Mg=Mi. Yes, it was an oversimplification. But if you insist... What EP says? That gravitational force is proportional to the mass? So, we get Mg/Mi and mass dissapears from the formula for the acceleration? Hence, in weak g fields objects fall with the same acceleration, correct?

Lets make it more formal. Fall=move. So 2 objects with different mass starting from the same point of 4D spacetime move by the same worldline trajectory, correct? But this result is rather trivial if we look at gravity as curved spacetime. How else it could be???

But even if was not trivial it is just a statement regarding the form of a worldline. So we get rid of the baggage about 'object', 'fall', etc etc. It is just mathematics and nothing more.

tom.stoer

Sep8-09, 02:29 PM

Sorry, but it's hairsplitting to ask for non-mathematical axioms and to explain later that what I gave you are not axioms but principles ...

You do not have to explain how the mathematical formulation based on the world line of an object emerge from the theory:
1) I know how it works
2) it's exactly my statement:
- you start with an "axiom" (you call it principle)
- derive the full theory in mathematical language
- and check how your axiom or principle is represented in the full theory

I agree that you can get rid of the baggage in the full theory, but I don't see how to manage it in terms of axioms. Can you formalize the Peano axioms?

Fra

Sep8-09, 05:45 PM

Some things to get the right background.

- Like I said before, I share a good deal of the sentiment of Jaynes and Ariel. Their "mathematics" is essentially that of probability theory. I am reconstructing another formalism, that is IMO a generalistion of probability theory as the answer to inductive inference.

- I share the vision of Ariel and laws of physics can be seen as rules of inference, however I differ in that I complicate their picture by suggesting he the inference system is subject to evolution. unless it's already obvious the analogy goes like this...

Standard physics is usually formulated as an initial value problem, where you have a initial state in a given configuration space, from which the future state follows from the laws of physics (equations of motion, or schrödinger equation etc). Not that this is a deductive logic.

premise ~ initial conditions, or the current state
deductive system ~ laws of physics

In the inductive inference view, the idea is that there exists no certain deductive system, only an inductive system. But you can still have different views on induction.

For example unpredictable phenomena like QM, where you can not deduce the outcome of an experiment, can then be said to be an form of induction, but one can easily describe this as a form of probabilistic deduction, or almost equivalently a deductive probability.

So QM still fits the deductive inference model if we accept that state of matter are only statistical.

But we have implicitly used probabiltiy theory and statistics here quite uncritical. But as I've argued several times, and like Smolin argued in his argument "against timeless laws" - which in my opinion is also an arrgument against deductive inference - this model is not universally sensible. It makse sense when we study a small subsystem, but not when a small system studys it's own environment.

So, the idea is that the laws of physics would be identified as the laws of inference. But since I reject the validity of standard probability, what do I suggest instead?

I suggest to replace flat usage of probability theory with a reconstruction of an intrinsic measure that is really a way to count evidence. Actually this is the original way Jaynes argued, he pondered over how to count evidence, and represent degrees of belief. Philosophical arguments was translated into axioms, when ultimately lead to a formalism that is standard probabiltiy theory. This is in his book "probabiltiy theory - the logic of science".

IMO, he makes some mistakes that makes me reject the reconstruction. He introduced the continuum too lightly, that's the first mistake, and it proves to be a key one.

You have to define how a rule looks (or a law or whatever) like, and you have to define how the negotiation between rules (which are mathematical entities) looks like.

Can you explain how this approach could look like mathematically?

What are your symbols, relations, axioms etc.? How does a rule look like?

To stick with close terminology to show that it's close to probability theory, I replace probability distrubiotn with microstate, and the space of distributions with microstructure.

I work with finite sets of natural numbers, to represent microstates.
Also, every microstructure has a complexity number, I call M.
Every microstructure has a eventspace volume k, this is the number of disntighuishable types of evidence/events.
The numbers of each set sum up to this complexity number.
The microstructure is the set of these sets, with complexity M.

From this point what I have is a discrete probability, where not only the event space is finite but - more importantly - the probability itself is discrete/quantized simply because there is no finite representation of the continuum.

similarly, by combinatorical considerations, you can define a natural way to measure one microstate relative to another one. If you calculate the probability for one microstate taking another microstate to be the prior, then in the expression you can separate information divergence and the complexity of the microstate in an interesting way.

You get P = w e^{-M{S_{KL}}} where S_KL is the information divergecen between the states, which is independent of complexity. w is a factor that scales with complexity, but w -> 1 asymptotically approaches as complexity -> infinity.

Thisi s very simple, but this is the seed to what later will generate physical actions. The least action principle is in this view, simply the principle of maximum probability, except that in my view, the "probability" is an INSIDE counting of evidence. And in the case of high complexity this also conicinced with the principle of minimum information divergence (minimum speculation), but this is not generally the case for LOW complexity.

Some postulates will be that for example the expected action of an inference system, is that which maximised the transition probability - this is the correspondence of the least action principle.

But this is just the starter, next I consider that an observer actually consists of sets of microsturctures (sets of sets) that have relations by means of transformations, which is really a form of recodign of information. Thus information (and evidence counts) can flow between the "spaces", and that an observer complex is infact a system of communicating spaces constructed in a special way.

THIS is where interesting things will happen. Becuase new logic appears here that does not comply to standard probability. For example quantum logic should be explainable as a result of inforamtion equilibrating between the dual spaces and their relation would explain how to make sense of out negotiations of X and P, when they belong to different spaces.

But there are alot of opne things here for sure.

But so far we haven't even gotten to the evolution part yet. By my idea is to start descrive how ANY inside view should look like, this is possible since the options are finite if you start at the low complexity limit.

Then one can see which combinations of observer complexes that can coexist so to speak.

Note that I start with a distinguishability index - not a spacetime. space should also emerge as a preferred index structure, certainly I expect the dimensionality to be related to stability of hte complexes. But I am not there yet :) the problems is that several problem are related so it really doens't quite work to solve one problem at a time; this is why even my very approach to this is evolutionary, I work on all things at once and make broad but slower progress.

You have to define how "rules act on rules": you have a negotiation process for which you need rules; "rules acting on rules" can therefore be negotiation between physical laws, but it can also be the evolution of some physical entity.

How and when do which rules interact? How are two (or three? four?) interacting rules selected? How do they "come together"? How does the DNA look like? How does mutuation, crossing-over and spawning of new rules look like?

How do you count rules or members of classes of rules in order to decide which rules are successfull = dominant?

What will our universum be? One master rule or a colletction of the most successfull rules?

process - which then becomes part of it and is subject to negotiation as well? what are your initial conditions?

Alot of questions, all justified. but each comment would be be long, and still incomplete due to the nature of the incomplete progress... need to goto sleep now. maybe the previous comments helped also on some of the latter questions?

---
some final comments on how the reconstructed inference system would differ from the standard probabilistic and entropic on of jaynes and ariel:

Each distribution would come with a natural kind of "mass", thus information has mass.
This serves as inertia when these two distrubions are forced into negotiation.
This intertia also fills a purpose in the process of increasing the complexity of the observer - this will I think relate to gravity (certainty attracts more certainty)

More importantly the reconstruction comes with a natural information mesure, no need to postulate a specific choices of entropy. The natural information measure comes in the form of probability of probability in the framwork I reconstruct.

But the major point is that the meaure I reconstruct, is not to be interpreted as a frequentist thing, or rely on ensembles of systems (say ensenmbles of universes) it is simply an inside COUNT of evidence. You need no ensemble or repatable experiments. The new concept is a proper evidence count.

/Fredrik

Fra

Sep8-09, 05:48 PM

Does anyone know what the latex formulas nowadays shows up as black unredable? I looked at old threads where they look fine?

Has the latex plugin to this site changed?

/FRedrik

Fra

Sep9-09, 07:22 AM

Note that I suggest a closer match between the scientific process and physical processes.

About science, it's undoubtedly so that the deductive system we call physical law is inferred or abduced from our experiecen with nature. In a sense we can say that the inference system itself, is inferred, and constantly evolving.

This is why my program is not conceptually consistent with the realist view of timeless physical law. Or put differently, my view of inference is that there is not objective timeless reality to the inference system itself! so the inference system itlsef is a result of an inference, this is the circularity that is the evolution in my view.

/Fredrik

Fra

Sep9-09, 07:27 AM

So the somewhat killing of realism that to a certain extent was initiated by the relational thinkers like Einstein and mach, and then QM, is not take take to it's full implication. I want to take this another level. And then away goes the realism of physical law.

I know alot of people think this would crash all we know, and without fixed deductive systems we are toast. But this is not so. We can just remind ourselfs that human science has not crasched in despite of it's deductive system is beeing inferred, and sometimes renegotiated. The human brain certainly doesn't crash.

On the contrary would I say that the opposite - a fixed deductive system - would risk going into a halt! I consider this conceptually related to someone Christine Dantas wrote about in some old posts and on her blog (don't remember) - that nature avoids deadlocks. IMO, she expresses something that is very close to this issue, but perhaps put in different words.

/Fredrik

tom.stoer

Sep11-09, 01:15 AM

I think I understand your point. Fact is that you have to specify some physical laws that apply here and now. Then there is the question how they can change in time (what is time?)

We must not mix the following approaches:
1) the believe in the existence of the moon even when nobody is looking at it
1') the believe in Kepler ellipses even when there are no planets
2) the description of (some of the aspects of) the moon by a mathematical framework

1) is the starting point for any kind of realism
1') is the starting point for something like structural realism
2) comes a a later stage and tries to map some aspects of 1) or 1') into a mathematical framework

What Dmitry67 is discusses is to identify 2) itself with something like 1') and 1) As I tried to explain I am not convinced.

As I understand ... And then away goes the realism of physical law. it is an objection against 2) and some interpretations, not against 1) itself.

Now you can say that its useless or even nonsense to believe in 1) if you can neither be sure that 2) applies nor be sure that 1') applies NOW. My believe is that at least 1) will always survive as long as you do not go for solipsism.

So at which level does you inference "happen", 1), 1') or 2)

Fra

Sep12-09, 11:27 AM

I'll comment more later. I've better from the flu and just got back from a business trip to paris. The internet at the hotel was a disaster, it was working on and off intermittently and I got fed up with trying to use it. Ontop of that they had multiplexed the phone on the ethernet wires in the building so when I plugged in the laptop the phone didn't work. No wonder the connection was unstable.

/Fredrik

Fra

Sep13-09, 05:52 AM

I think I understand your point. Fact is that you have to specify some physical laws that apply here and now. Then there is the question how they can change in time (what is time?)

I certainly acknowledge these questions. Here are some incomplete further comments.

> Howto specifiy current law

This can be interpreted in severa ways. I guess the most obvious and honest answer is that our best state of physical law is simply the standard model. Because after all, that is extremely successful.

One would have to distingusih acknowledging the standard model to be the best of our current knowledge and the quest for candidates of improved models, that solves some of the open questions, that have both possible experimental preductions but also refer to conceptual and consistency issues in the current model.

The way I am reasoning would also suggest a change in the framwork in which the standard models if phrased. This in practice means that the suggestion I have would imply a minor revolution of thinking. It's not just that I suggest shifting a couple of parameters in the standard model, I'm suggesting a completely different framwork for posing the scientific questions. Thus do I expect a revolution type of evolution.

But until then, there is no question that the standard model (which it's flaws) is the best de facto model we have.

So howto translate the "standard model" into the new framework? The idea is to first of all work on the basis I referred to previously, and then try to find the emergent observer complexes and emergent stractures, and hopefully match those structures with the standard model. so in short, the new ideas would suggest a new framwork that constrains the models, and then the standard model and the body of experimental data can be used to "train" or tune the new model. This "training" would not be part of the proper inference I refer it, it's simply a practical thing needed to translate the "current state" between two frameworks when the framework is revolutionized.

What is time is a very big equestion in itself, I think your questions are well motivated and firing so many of them into one thread leaves me no choice but to be brief. Time in my view is somewhat analogue to the thermodynamic(TD) arrow of time, but the difference is that remember that ordinary TD is founded on plain probability theory. I was previoulsy suggesting a reconstruction of that, wich important differences, and in that sense similarly will the arrow of time we more complex. In particular will the usually issues ot heath death not necessarily apply to such evolutions.

Also, since my construction is based on evidnce count, it is a subjective inference system and not objective. This also naturally renders my reconstructed "thermodynamic arrow of time" subjective, or observer dependent. It's my conjecture that this can be entirely consistent with relativity in the appropriate approximation.

Since a basis trait of the interacting inference systems is that the "inconsistencies" between two inference systems does not halt the system - instead it DEFINES a new interaction, and a new symmetry between inference systems. In my view symmetries of laws are emergent in this way. This would also suggest a completely new way to seeing at symmetry breaking etc. Again it's a different way of thinking than the standard model framework.

We must not mix the following approaches:
1) the believe in the existence of the moon even when nobody is looking at it
1') the believe in Kepler ellipses even when there are no planets
2) the description of (some of the aspects of) the moon by a mathematical framework

1) is the starting point for any kind of realism
1') is the starting point for something like structural realism
2) comes a a later stage and tries to map some aspects of 1) or 1') into a mathematical framework

What Dmitry67 is discusses is to identify 2) itself with something like 1') and 1) As I tried to explain I am not convinced.

As I understand it is an objection against 2) and some interpretations, not against 1) itself.

Now you can say that its useless or even nonsense to believe in 1) if you can neither be sure that 2) applies nor be sure that 1') applies NOW. My believe is that at least 1) will always survive as long as you do not go for solipsism.

So at which level does you inference "happen", 1), 1') or 2)

I will respond more to this later. But in short, I certainly see the difference between some of the old style realism, and the more modern less objectionally "structural realism" which is when you have a realist view of physical laws.

I reject both as fundamental.

however, one very important distinction I would like to add is that there is a difference between

1. The rationality in a belief in a fixed basis of your own actions - this fixed basis can be thought of as realistic.

2. the idea that realist elements are timless, eternal and not subject to inference.

Even in my view there is a defendable rationality between action upon certain beliefs AS IF they were elements of reality in the realist sense. This is because due to the limited complexity of the inference systems, some uncertainties can not be quantified/measured. This is the lowest level in the information hierarchy, and IMO consititues the most stable physical law.

It's the idea of rational action, the rational action acts upon it's premises regardless of wether this will later be changed.

IMO, the only influence on the action that the belive in realism has, is that your actions are so constructed as to NOT QUESTION the validity of this. This exists also in my way of thinking ,but I do not mix up this rational action based on non-deductive inference and imperfect initial conditions with realism in hte sense it's usually meant.

I consider Dmitry's reasoning to have strong realist traits. About your view I'm not I formed an opinon yet, but it seems that I'm probably closer to your reasoning than to Dmitrys. Buit I could be wrong.

/Fredrik

ConradDJ

Sep13-09, 10:16 AM

There is definitly a physical reality, but if it is independent from any perception is not clear to me. Especially in quantum mechanics it's no longer clear how to make a cut and define exactly this external physical reality.

Compare this to a rainbow: a rainbow somehow exists independent from our perception of the rainbow, but the independent existence reduces the rainbow to a collection of raindrops, light rays and geometrical concepts. This collection could be called its reality / existence, but it can hardly be called rainbow ...

Unfortunately for the physical reality of quantum objects we are not able to say what corresponds to the raindrops, light rays etc. Atoms? quarks? fields? quanta? operators and Hilbert spaces?

"Does the moon exist even if nobody looking at it?"

Now the problem for me is that even if I deny that q.m. can tell us anything regarding "reality", I have the feeling that there is something behind this "empirical film" of the world...

So my conclusion is a) that there is a mind-independent, external reality but b) that we cannot even know about the very concept / meaning / notion of its existence. We do not know to what the "rainbow" reduces - but we are definitly sure that its reduction causes it to lose its "rainbowness".

Tom -- I think you're pointing toward something fundamental here, that doesn't become quite clear.

The rainbow is not "mind-dependent" -- in that a camera located at the same place would "see" the rainbow too. But its "rainbowness" -- i.e. the aspect of its structure that's not captured in a description of raindrops and light-rays per se -- depends on the point of view from which it's seen.

Classical physics was based on the assumption that a complete description of the world can be developed without reference to "points of view" -- or to put it more generally, without reference to any specific physical conditions under which measurements are possible.

Relativity then required that spacetime "points of view" be taken into account. And QM generalized this requirement to include any physical conditions of measurement.

So 20th-century physics raises a problem that I don't think can be solved so long as we think in Cartesian / Kantian terms -- i.e. "external reality" vs "mind-dependent" appearances. Your rainbow represents the missing third category -- i.e. the aspects of the world's structure that belong to the real, "external" physical world, just as much as the moon does -- but aren't describable as objects "in themselves" (light rays, raindrops).

The third category is what Rovelli points to (in his Relational QM paper) when he says physics is about "the information things have about other things". This also describes Fra's project, though his premises and starting-point differ from Rovelli's.

As for me, I would frame the issue a bit differently. I'm trying to understand the relational structure of the "external world" in terms of the conditions under which physical interactions can communicate information, in the context of other kinds of physical interaction.

But the basic point is that physics includes not only structures that can be described "in themselves", but also structures of relationships between things, like the rainbow. The classical assumption that the latter structures are reducible to the former seems now clearly untenable... so the deep unresolved issue in contemporary physics (as Smolin and many others have argued) is understanding how to describe what's going on in physical relationships.

Unfortunately, we're all so used to the dichotomy of "mind-dependent" vs. "mind-independent" that it's hard to grasp this challenge with any clarity. What you call the "empirical film" confuses what appears to us, subjectively, with the structures in the world itself that make physical "appearances" -- rainbows -- possible.

Dmitry67

Sep13-09, 10:28 AM

THere is another interesting option as I mentioned in another thread.

Very likely the complicated things like consciousness/mind cant be explained based on the properties of the parts they consist of. Even more, if the world is deterministic, mind can be... well... I cant say 'non-deterministic', but rather 'non-applicable'.

tom.stoer

Sep13-09, 10:30 AM

Hi Frederik,

I think I somehow start to understand your (excellent) ideas

Howto specifiy current law ... our best state of physical law is simply the standard model.
Currently - yes.

... would also suggest a change in the framwork in which the standard models if phrased. ... It's not just that I suggest shifting a couple of parameters in the standard model, I'm suggesting a completely different framwork for posing the scientific questions.
I agree - at some time or stage this is required.

... I certainly see the difference between some of the old style realism, and the more modern less objectionally "structural realism" which is when you have a realist view of physical laws.

I reject both as fundamental.
Why? Can you explain in more detail, please?

... there is a difference between

1. The rationality in a belief in a fixed basis of your own actions - this fixed basis can be thought of as realistic.

2. the idea that realist elements are timless, eternal and not subject to inference.
I never mentioned that explicitly as it was clear for me from the very beginning. Whatever this reality is, there is no requirement that it's timeless - whatever timeless means :-)

... About your view I'm not I formed an opinon yet, but it seems that I'm probably closer to your reasoning than to Dmitrys.
let's wait and see ...

Fra

Sep14-09, 12:23 AM

Hello Tom,

... I certainly see the difference between some of the old style realism, and the more modern less objectionally "structural realism" which is when you have a realist view of physical laws.

I reject both as fundamental.

Why? Can you explain in more detail, please?

My way of abstraction of physics is a reconstructed information theoretic view that follows from the reconstructed "evidence count theory". But in short in this view, both types of realist views are a result of a physical inference. The only difference is that the structural realism is more sophisticated since it's somehow recodes the observational data to find the invariants (the laws) - in this sense, if I have to choose I would prefer structural realism, but it still suffers from the same principal disease ;)

This is pretty much what relativity did as well, when the reality of absolute space and motion was rejected, the rescue was to find the transformations that connects the relational views. And of course this structure (symmetry of spacetime) is more stable than the previous views.

A prime examply of this reasoning is Rovelli's reasoning, in this various papers, partial/complete observables etc etc. It's one of the issues I have with this reasoning, because he doesn't seem to take the observers inside view seriously, since he keeps refering to the transformations between observers, while not acknowledging that hte inference of these transformations/symmetries that he considers to be the more physical thing, can only take place relative to the inference machinery defined by an inside observers. In this sense, I don't think Rovelli's reasoning is self-consistent - from the point of view of physical interaction as inference. The paradoxal part is that in this RQM paper he at least partially aims to this, but in the paper there is a turn wheere he avoids some important keys. (For example the meaning of "probability" - that's exactly the question I acknowledge and the reason why I want to reconstruct it)

This is also how QM saved determinism. By bundling the unpredictable outcomes into statistical distributions, the determinism was recovered at statistical level.

It's a repeating pattern, and it's certainly a natural one, and a rational one. I do not object to that itself, on the contrary. But the symmetries or laws, found from a previous diversion of observations made by a different observers, the relationa between the observers, recovered a connection between their observations, by symmetry transformations.

But as this is described, this symmetry is inferred from experience in one observers view, and to this particular observer this reasoning seen in isolation is on par with any other inference. An in general an inference, may it be about the state of an small system in the environment, or a statemeny about the symmetry of actions of all systems observed in your record, is nothing more than a basis for his actions. It's not possible to turn this inference into a deduction and arrive at a certain "symmetry". What can happen, is that the uncertainty of hte symmetry is not distinguishable, and in this case it's IMO rational to act as if it was an element of reality, but that doesn't make it universally, timless and objectively real.

I never mentioned that explicitly as it was clear for me from the very beginning. Whatever this reality is, there is no requirement that it's timeless - whatever timeless means :-)

Yes, that's true. I like the point Smolin made in one talk on this, where he pointed out the ambigous notion of eternal law when the universe is only 14 billion years old - and still growing older.

The reason I used the word is that I have a feeling that alot of people that perform realist type of reasonining (also structural realists), doesn't seem to be bothered by the ambigous notion of what realism is, since if time is on one hand realtive, if the realist elements aren't eternal then exactly what does it mean? This realism seems to me to be a poorly defined guide.

OTOH, the practical difference to the immediate action of someone, between the old style realismm and just the rational action view I hold is probably non-existent. But somehow most realists doesn't seem to think of this of an opinion as as something that just influences the action but rather something more. I find that guide to be very unclear, therefore I reject it.

/Fredrik

Fra

Sep14-09, 06:56 AM

Some additional comments...

We must not mix the following approaches:
1) the believe in the existence of the moon even when nobody is looking at it
1') the believe in Kepler ellipses even when there are no planets
2) the description of (some of the aspects of) the moon by a mathematical framework

1) is the starting point for any kind of realism
1') is the starting point for something like structural realism
2) comes a a later stage and tries to map some aspects of 1) or 1') into a mathematical framework

What Dmitry67 is discusses is to identify 2) itself with something like 1') and 1) As I tried to explain I am not convinced.

I probably lost track of that part to be able to comment. I recall from past threads that Dmitry is more of realist than me at least. But if he suggest that these are somehow versions of each other than I sort of agree. They all fit into my inference view.

Now you can say that its useless or even nonsense to believe in 1) if you can neither be sure that 2) applies nor be sure that 1') applies NOW. My believe is that at least 1) will always survive as long as you do not go for solipsism.

Like I tried to say, I distinguish between the *rationality of belief* that does impact your action, and an illusion of some external reality to this belief.

To make another association/analogy here, there are some models on how the human brain works that considers a form of feed-forward state machine where the action of the machine contains expectatins of the future based on the past. this view is basically that the brain is an inference system to predict the future, and learning could then be feed-back which is driven by the reaction from the environment depending on the expected future vs that actual future.

I don't suggest we should turn this into a discussion of the brain or conscioussness but there are analogies here that might help grasp the idea, and if you think about it there are some interesting connections to how actions are formulated by means of feynmann style sume over paths, that is in effect a kind of action based on expected evolutions based on an initial condition.

This QM logic, apparently works, but if we could find a deeper understanding of it, in a larger context, merging it with relativity would I think be easier.

So at which level does you inference "happen", 1), 1') or 2)

Mmm I'd say probably all three, unless I misunderstood your question?

/Fredrik

tom.stoer

Sep14-09, 07:41 AM

... I think you're pointing toward something fundamental here, that doesn't become quite clear ...

The rainbow is not "mind-dependent" -- in that a camera located at the same place would "see" the rainbow too. But its "rainbowness" -- i.e. the aspect of its structure that's not captured in a description of raindrops and light-rays per se -- depends on the point of view from which it's seen.

... raises a problem that I don't think can be solved so long as we think in Cartesian / Kantian terms -- i.e. "external reality" vs "mind-dependent" appearances. Your rainbow represents the missing third category ...

ConradDJ,

you are definitly right. My feeling is that our discussion (and possible science) scratches the surfaces of something deeper than just new equations or just another discussion about Cartesian/ Kantian / ... reasoning.

Regarding the rainbow: it is both "external" and "internal" - and it is "relative".
It's "external" as it "consists" of fundamental "things" like raindrops, light rays etc. I don't want to say that these external things or their existence in itself is understood to 100%, I only want to stress that a rainbow has "aspects" that are somehow independent from any observer.
It is "internal" as its representation in our brain or mind (whatever this is) depends on us. The color "red" is not a piece of the rainbow's existence but it's the mind-internal representation of some specific wave length of a specific light ray between a raindrop and my retina.
It is "relative", as e.g. it's position depends on the position of the sun, the position of the raindrops and my position.

The "external existience" is justified by the miracle argument: It would be a miracle if there were nothing else but "mind-internal" existence along with coinciding phenoma perceived by different individual observers. At least some aspects of the rainbow are perceived identically (similarly) by different observers (including the camera). This is a strong hint (not a proof) that there is something that "exists even if nobody looks at it".

The problem with this "external existence" is that we cannot say what it really IS, because our perception is always filtered by our senses, certain devices etc. So it seems that there IS some regular structure behind the phenomenological level which has an own, independent, external existence.

The structural realism deals with this regular structure but (at least partially) ignores the problem that the "physical laws" are not only relations between "external entities" but also relations between an "external entity" and "me". The position of the rainbow is a perfect example. Therefore the clear cut suggested by realism does not work - neither for old-fashioned "naive realism" nor for any other school of though.

It becomes clear when we start discussing the terms "external" or "independent". They point towards something that exists w/o "me", but as soon as we try to pinpoint them, theyescapes from any sound definition.

Now the problem is that we are used to think in two categories - objective and subjective. The objective, realistic position is problematic as explained above, but the subjective one is problematic as well. If you look at idealism, phenomenology or positivism you always have the feeling that they miss an important point. If they (as positivists do) insist on "predicting experimental phenomena only" they neglect "the existence of the moon if nobody looks". They claim that the whole discussion is meaningless, but if you look at a positivist getting up, going to the kitchen and using his coffee machine you cannot avoid the impression that the coffee machine existed all over the night and has not been created by opening the kitchen door (other positivists create their coffee machine by switching on the light; fortunately one coffee machine can be re-created eiter way :-) This is OK as long as you are clear and aware about this blind spot. If you build an subjective ontology that does not even mention this blind spot you are on our way towards solipsism.

What I am trying to say is that I like Kant's idea of the "thing-in-itself" that is unreachable by our senses, but that serves as an "x" around which we construct our reasoning. This "x" is like the rainbow itself (or a your shadow) - if you try to catch it, it slips away, but nevertheless it's clear that it is "there".

I think that every ontology either explicitly using the cartesian cut or explicitly denying the cut is doomed to fail. The cut exists in some sense, namely as a structure within our categories of thinking, so we must not deny its existence.

Perhaps the situation compares somehow to the early years of quantum mechanics. Neither waves nor particles are the correct description of nature. It is neither exactly one of these pictures, nor is it a naive combination of them. It is something deeper that only in some rare cases (experiments) presents itself in such a simplified way.

In a similar way I expect that a deeper level of the (description of) physical reality will reveal a harmonization of these different and mutually exclusive points of view - idealism (subjectivism) and realism (objectivism) ...

Fra

Sep14-09, 08:28 AM

Tom I'm starting to see your reasoning, but let me ask, do you consider yourself somewhat of a structural realist?

I only want to stress that a rainbow has "aspects" that are somehow independent from any observer.

To me the questioning of what the rainbow is or isn't wouldn't take place without a context to encode it.

I'd rather like to say that there are aspects of the rainbow that are apparently independent of a choice of observers among a defined choice, but then certainly begs the question why are we constrained to the choice of observers that "happens to be in agreement"

That is basically questions is the one you raise here

The "external existience" is justified by the miracle argument: It would be a miracle if there were nothing else but "mind-internal" existence along with coinciding phenoma perceived by different individual observers. At least some aspects of the rainbow are perceived identically (similarly) by different observers (including the camera). This is a strong hint (not a proof) that there is something that "exists even if nobody looks at it".

In my view, it's not a conincidence at all. It's a result of evolution, and only those observers (read physical matter systems) that implements consistent inference systems are able to coexist in equilibrium. The disagreement between the systems implies interactions that forcefully deforms the inference machinerys.

Thus the "consistency" we see around us, is I think no conincidence at all. Just imagine that opposite, it would be wild and I presume destabilise in fractions of seconds.

So when did this evolution take place? I guess my personal idea is that this would (informally) have taken place very very early in what be today consider to be the big bang, at the point where the forces was indistiniguisahble and there was no localised matter. Probably at some point, the equilibration/laws of some of the basic laws was complete.

/Fredrik

tom.stoer

Sep14-09, 02:48 PM

Tom I'm starting to see your reasoning, but let me ask, do you consider yourself somewhat of a structural realist?
It's too early to answer this question; but I am definitly MORE a structural realist than a naive realist.

... It's a result of evolution, and only those observers ... that implements consistent inference systems are able to coexist in equilibrium.
I don't agree. If you insist on evolution of the observes' rules, you have to answer what the driving factors of this evolution are. Every evolution takes place in an environment which decides about the "survival of the fittest". So again you are refering to something that is objective = external to the observers.

Fra

Sep15-09, 12:23 AM

If you insist on evolution of the observes' rules, you have to answer what the driving factors of this evolution are. Every evolution takes place in an environment which decides about the "survival of the fittest". So again you are refering to something that is objective = external to the observers.

Yes, of course. But i think this is a bit tricky, because in my view EVERY inference is made fomr the point of view of an inference system (inside observer) - this includes the decription of the evolution.

Some things are simply undecidable, or unpredicable, and this is in particular hte observers OWN FULL evolution. I suggested that an observer is a predictive system of the future events whose actions follows from this. But certainly no observer can KNOW the future. In particular not it's own future.

To explain the meaning of my idea of the subjective basis for the "environment of an observer", then the trick is to consider a second observer B. You have one observer B, observing it's environment. And this observer might distinguish more or less coherent subsystems in his environment (say one subsystem A), and this observer can thus try to understand the ACTION of these subsystems(A), and B can then describe the evolution of A relative to the observed B-subjective embedding of A.

This is why it's like smolin pointed out a large different between
1. observing an isolated subsystems, (which is effectively the case in particle lab experiments) since the observing environment is enclosing the observed system effectively.
2. a small observer observing it's own overwhealming environmnet.

So your point is good, but I have thought of that and I do not talk about an objective evolution, I suggest that there are only inside views even of the evolution itself. BEcause ultimately the evolution of law, and the evolution of states - as per law, are really principally the same in my view, the different is that the evolution of time and normal timevolution takes place at different levels in the hierarcy of the inference system.

Also on top of this, it is also admittedly unavoidable that every single thing I say here, are implicitly conditional on my current evolved brain. There is nothing whatsoever I can do about this. But it's good enough for me.

So I hope I tried to make the point. I am not envisioning this evolution as an objective evolution. Rather there are several views of the evolution as well. Clearly the view an observer has on it's own evolution, is simply the more simplified normal timeevolution, which is defined only differentially. As the actual time progreses, the feedback of the environment might generally induce a revision of the inference system in ways that is of course by construction completely and fully undecidable from the pooint of view of the observer itself.

However, that does not mean that this evolving inference system would be totally unpredictable for another (usually much larger observer).

It's exactly in this sense I distinguish between the inside view of the players in say a particle experiments. This particle I think simply have no clue, they can not predict their own future very well - which is revelaed in the way they act - their actions encode their "simple" expectations.

OTOH, the massively complex laboratory frame rules by reasonably intelligent human beeings can predict the future of these particle more than they can themselves do, because
1. we have much more information
2. we have a muhc more developed inference system

Does that make sense?

/Fredrik

Fra

Sep15-09, 12:40 AM

The idea that there are only inside views of the evolution as well, is also why I think that the environment and observer evolve together. Both are needed. It's like spacetime and matter. One without the other makes no sense. So I think the inflation of space is a process that must by consistency of this idea, go hand in hand with the creation of matter. They somehow both drive each other.

Ie. the evolution doesn't take place in an external fixed environment, because the environment is itself evolving, because the environment is simply another inference system. It's like you have two inference systems fighting each other, and the one that predicts the other one better wins control.

/Fredrik

ConradDJ

Sep15-09, 07:49 AM

The problem with this "external existence" is that we cannot say what it really IS, because our perception is always filtered by our senses, certain devices etc...

The objective, realistic position is problematic ... but the subjective one is problematic as well. If you look at idealism, phenomenology or positivism you always have the feeling that they miss an important point.

Tom – Your post makes a lot of sense. In the background of all this thinking is that Cartesian sense of being “inside our heads” and looking “out” at an external world through some filtering screen that may or may not allow actual information to get through. As radicalized by Kant, it’s the sense of a mysterious unknowable reality “out there” that our mysterious consciousness “in here” can never get to.

From this viewpoint, the fact that information has to be communicated through physical interaction is seen as something negative. Ideally the mind (as something existing “in itself”) should have direct, unmediated access to the “external reality” (as it is “in itself”). This notion of what it would mean to have genuine knowledge is at the root of our tradition, from Plato to Hegel.

But of course we humans are physically “out there” in the world interacting with things, and with each other. To the extent we develop an “internal” consciousness, it grows out of this communicative environment. And though our senses and devices certainly have their limits, what’s really remarkable is how much information is there in this interactional environment, and how thoroughly we’ve been able to explore it.

In fact, QM seems to be telling us that all the determinate information there is in the world gets communicated through interaction. Ultimately,“behind” the interaction there isn’t any definite “thing in itself” to be known, but only – as described by the wave-function – some kind of structured potential for communicative interaction.

So it seems as though the kind of being your rainbow has, may be what’s fundamental. Both the “external existence” of things and our own “internal existence” seem to depend on the very special character of the interactional environment between us all, that can actually define all this information.

In any case, I don’t see the problem in present-day physics as one of struggling to grasp a mysterious reality we can’t experience. I think the hard problem is one of understanding the structure of what we do experience and measure – not as something going on “in our heads”, but as what goes on “out there” in the physical world that constitutes our shared informational existence.

I tried to point out in another thread why this is a hard problem. It’s not that we lack access, but that we have so many ways of access, that all depend on each other.
http://www.physicsforums.com/showpost.php?p=2319688&postcount=3

I think what we lack is an adequate analytic approach to this kind of information-system. And the more basic problem is that in these debates over objective vs subjective thinking, what’s so remarkable about our physical communications environment is just taken for granted -- or treated as though it were an obstacle to true knowledge.

tom.stoer

Sep16-09, 04:20 AM

... the evolution doesn't take place in an external fixed environment, because the environment is itself evolving, because the environment is simply another inference system. It's like you have two inference systems fighting each other, and the one that predicts the other one better wins control.

I have no problem with the idea of an evolving environment. Whar I miss is the expolanation for "survival of the fittest", population, "... wins control". What are the rules to decide what fits to what? what are the rules for producing predictions and comparing them with "reality"? what does it mean that one systemwins over the other? what happens to the winner (loser)? What sets the "timescale" or clock for the evolution (it's of course not the physical time).

tom.stoer

Sep16-09, 04:43 AM

... is at the root of our tradition, from Plato to Hegel.
I agree.

Ultimately,“behind” the interaction there isn’t any definite “thing in itself” to be known, but only – as described by the wave-function – some kind of structured potential for communicative interaction.
Yes, something like that.

..., I don’t see the problem in present-day physics as one of struggling to grasp a mysterious reality we can’t experience. I think the hard problem is one of understanding the structure of what we do experience and measure – not as something going on “in our heads”, but as what goes on “out there” in the physical world that constitutes our shared informational existence.
You are right, it's not a problem directly related to physics, it's more are problem of the ontological position of present day physics. The question is critical to physics because currently I do not see that philosophy has managed to understand the most important results from the last century (QM, GR). You can see that simply be the terminology we are using - it' out-dated! Philosophy stopped to develop a fundamental ontology as they stopped to understand the physical progress = with the beginning of the 20th century ...

The more I think about all these ideas I come to the following conclusion:
1) either we accept that the physical reality (including us as observers, physical laws and their evolution, ...) indeed IS a purely mathematical framework w/o any additional baggage (like interpretation, recipe for application, ...) that is embedded in a mathematical multiverse consisting of all (sound) frameworks
2) or it is impossible to find a consistent ToE at all because by Goedels theorem every candidate-ToE would allow to ask questions like "is THIS ToE consistent" - and of course we know that the answer can be given iff (if and only if) the ToE is inconsistent - and if it cannot be given, the ToE could be consistent but this is not provable.

I do not like this conclusion, but I do not see a way out.

John86

Sep16-09, 04:47 AM

I have no problem with the idea of an evolving environment. Whar I miss is the expolanation for "survival of the fittest", population, "... wins control". What are the rules to decide what fits to what? what are the rules for producing predictions and comparing them with "reality"? what does it mean that one systemwins over the other? what happens to the winner (loser)? What sets the "timescale" or clock for the evolution (it's of course not the physical time).

"There are no winner and losers" it's just quatum mechenical evolution at work call it uncertainty. the consequence of this is that it disturbs last strong holds of realism. this will although ultimately have no certain consequences for our daily classical world though.

Fra

Sep16-09, 04:53 AM

I have no problem with the idea of an evolving environment. Whar I miss is the expolanation for "survival of the fittest", population, "... wins control". What are the rules to decide what fits to what? what are the rules for producing predictions and comparing them with "reality"? what does it mean that one systemwins over the other? what happens to the winner (loser)? What sets the "timescale" or clock for the evolution (it's of course not the physical time).

Ok, I guess you demand something very explicit here, and of course so do I.

I do have some partial answer to your questions but they aren't very mature or sufficiently developed to knock some someones head quite yet. Every question here is very well justified. I'm not hiding from them :)

But given the work in progress instead of trying to convince you by more fuzzy or incomplete arguments I will settle with that I am trying to find explicit answers. The ultimate argument will certainly have to be developed and verified predictons.

/Fredrik

Fra

Sep16-09, 05:11 AM

Just one more fuzzy comment if it helps, but I think I already said this previously.

I have no problem with the idea of an evolving environment. Whar I miss is the expolanation for "survival of the fittest", population, "... wins control". What are the rules to decide what fits to what? what are the rules for producing predictions and comparing them with "reality"? what does it mean that one systemwins over the other? what happens to the winner (loser)? What sets the "timescale" or clock for the evolution (it's of course not the physical time).

"the population" ~ matter or "confined energy" systems

"intrinsic inference system" ~ encodes the physical action of above matter

the looser ~ gets destabilized (looses mass/energy) and are not longer part of the population, and thus neither is the inference system / action the looser encoded

the winner ~ either maintains status quo, or better grows more degrees of freedom (~mass)

This is why as in high energy experiment you break up the matter systems into smaller parts, the smaller the parts the less encoding capacity do we have to encode complex interactions, and therefore would one expect unification at the zero complexity limit.

The complexity ~ mass, of a system is the natural regulator cuttoff, that constrains the space of possible inferences. This would suggest a feynmann kind of paht integral but with a built in renormalisation, the natural cutoff is simply the complexity of the context, the observer, than encodes the integral.

IE. a "simple observer" can not possibly "observe" (infere/abduce) a sufficiently complex law in the environment, therefore the immediate actions of this observer must also be invariant with respect to this indistinguishable complexity.

A successful observer, who are able to predict the environment is effectively conquering degrees of freedom of the environment.

/Fredrik

John86

Sep16-09, 05:16 AM

Yes, that's true. I like the point Smolin made in one talk on this, where he pointed out the ambigous notion of eternal law when the universe is only 14 billion years old - and still growing old

what role does time play before that phase

Fra

Sep16-09, 05:42 AM

what role does time play before that phase

My personal view is simply that at that supposed point, it is not possible to encode anything that implements any kind of arrow of time, therefore I think time is simply undefined, or a question that isn't raisable, because the context neede to encode an arrow of time isn't there.

/Fredrik

ConradDJ

Sep16-09, 05:55 AM

I'd rather like to say that there are aspects of the rainbow that are apparently independent of a choice of observers... but then certainly begs the question why are we constrained to the choice of observers that "happens to be in agreement"

In my view, it's not a coincidence at all. It's a result of evolution, and only those observers (read physical matter systems) that implements consistent inference systems are able to coexist in equilibrium. The disagreement between the systems implies interactions that forcefully deforms the inference machinerys.

Thus the "consistency" we see around us, is I think no coincidence at all. Just imagine that opposite, it would be wild and I presume destabilise in fractions of seconds.

I have no problem with the idea of an evolving environment. What I miss is the explanation for "survival of the fittest" population, "... wins control". What are the rules to decide what fits to what?

Fredrik – The issue with this language about “equilibrium” and “destabilzing” – as I’m sure you recognize – is that there’s an implication that time is running on in the background, and some systems survive longer in time than others. (That of course makes sense for evolution in biology, where the issue is indeed the survival of complex systems over time, against the threat to their stability / integrity posed by the physical environment.)

I don’t think this is what you have in mind, so the question is how to frame the issue differently. In physics, it seems that the fundamental issue is how to define (determine) information in the first place – including information about the time-sequence of events, etc. The “threat” posed by disagreement among observers is not that some equilibrium state will break down, but simply that the conflicting information provides no definite basis for further information to be defined.

It’s only to the extent that all present “observers” agree on information, that it gets passed on as a basis for future agreements. “Future” here does not refer to a background time-continuum so much as to “what’s next” in the evolutionary process itself. I’m thinking that distinction will make sense to you. Here it’s not a matter of “survival” over a period of time – the issue rather is what gets defined / agreed on “here and now” that can be “passed on” as a basis for other moments of observation, both here and elsewhere. There is something like "time" only insofar as this progressive determining-and-agreeing keeps happening.

And there are various levels of agreement – e.g. agreement about specific facts, and agreement about the general “laws” or patterns into which all the facts must fit. The one refers to the ongoing evolution of information, moment by moment, as we observe things, while the other refers to patterns that evolved long ago, which are the preconditions for our coming to agreement about specific facts. (If nothing were lawful and predictable, clearly there could be nothing like observation or communication.)

And of these general patterns, some are presumably more "primitive" and others evolved "later" based on those "earlier" patterns.

But to me, the crucial point is that we’re not talking about some mysterious process that takes place only at the Planck scale or at the beginning of time – this is something that still happens in every “observation” and every communication, all the time. So the problem is one of sorting out the tangle of many different kinds of physical interaction that make up our present-day “communications network”, to try to see which are the more “primitive” and which the more “highly evolved” interaction-patterns.

By the way, I'm glad you're being pushed to get more of your unfinished work out in the open!... though some of this is way over my head.

-- Conrad

BigFairy

Sep16-09, 06:13 AM

It certainly has a lot to do with the ideas ever so proposed

ConradDJ

Sep16-09, 06:43 AM

You are right, it's not a problem directly related to physics, it's more a problem of the ontological position of present day physics. The question is critical to physics because currently I do not see that philosophy has managed to understand the most important results from the last century (QM, GR). You can see that simply be the terminology we are using - it's out-dated! Philosophy stopped to develop a fundamental ontology as they stopped to understand the physical progress = with the beginning of the 20th century ...

Yes, I very much agree. There was actually a very important breakthrough in Heidegger's Being and Time, published just as the QM formalism was getting established in the late '20s. (Heidegger was certainly aware of the turmoil in physics, though I'm sure he made no attempt to understand it.) But Being and Time was published as the first half of a project that he never completed, and his later work did not succeed in making any connection with the sciences.

I spent years (in long-ago grad-school days) deciphering his work, and learned a lot from it -- but I was tremendously disappointed by his "followers" (not to mention his detractors). I couldn't find anyone who was actually doing anything useful with his work, and for the most part it was understood merely as another contribution to phenomenology, relevant only to understanding human existence. His task of fundamental ontology was never taken up.
The more I think about all these ideas I come to the following conclusion:
1) either we accept that the physical reality (including us as observers, physical laws and their evolution, ...) indeed IS a purely mathematical framework... in a mathematical multiverse consisting of all (sound) frameworks
2) or it is impossible to find a consistent ToE at all because by Goedels theorem every candidate-ToE would allow to ask questions like "is THIS ToE consistent"...

I do not like this conclusion, but I do not see a way out.

But I don't see mathematical consistency as the issue. For one thing, mathematics and logic only have meaning because the physical world gives us distinct, identifiable objects that persist through time. "A=A" may seem incontrovertible, but in the very early stages of the universe there would have been nothing to which this statement corresponds.

I think we fall back on Platonic notions of a world made of mathematics, only as a default -- because it's so difficult not to take for granted how well the physical world works, to define things and relate them to each other in so many ways. We treat physical existence as if it were a logical "on/off" switch -- either something exists or it doesn't. But to "exist" means to participate in a very complicated web of ongoing physical relationships with other things that exist. (This was Heidegger's basic point about "the meaning of being" -- that it has to do with "being-there" or "being-in-the-world"... as opposed to treating it merely as a logical "is"/"is not".)

And though we can model distinct aspects of this web in mathematics, with great success, it doesn't follow that it is essentially a mathematical structure. What Fra is trying to develop is a functional model -- in that only a functional system (e.g. a self-replicating one) can be imagined as evolving, in the sense he intends. Likewise Smolin in The Life of the Cosmos... where the functionality of the universe is taken to be a weird kind of self-replication.

Smolin's idea seems to me far-fetched, physically, and uninteresting from a philosophical standpoint. But I think his point is well-taken that the physical world looks in many ways like a highly-functional and indeed highly-evolved system. So the issue is how to define its basic functionality -- what exactly it means that the world "works" to support physical existence -- not just human existence, of course.

tom.stoer

Sep16-09, 08:36 AM

"the population" ~ matter or "confined energy" systems

"intrinsic inference system" ~ encodes the physical action of above matter

the looser ~ gets destabilized (looses mass/energy) and are not longer part of the population, and thus neither is the inference system / action the looser encoded

the winner ~ either maintains status quo, or better grows more degrees of freedom (~mass)

This is why as in high energy experiment you break up the matter systems into smaller parts, the smaller the parts the less encoding capacity do we have to encode complex interactions, and therefore would one expect unification at the zero complexity limit.

The complexity ~ mass, of a system is the natural regulator cuttoff, that constrains the space of possible inferences. This would suggest a feynmann kind of paht integral but with a built in renormalisation, the natural cutoff is simply the complexity of the context, the observer, than encodes the integral.

IE. a "simple observer" can not possibly "observe" (infere/abduce) a sufficiently complex law in the environment, therefore the immediate actions of this observer must also be invariant with respect to this indistinguishable complexity.

A successful observer, who are able to predict the environment is effectively conquering degrees of freedom of the environment.

wow - interesting idea - I have to think about that for a while:-)

tom.stoer

Sep16-09, 10:15 AM

ConradDJ,

thanks for mentioning Heidegger. I studied Sein und Zeit (I am German therefore I need no translation :-) - but I think I only scratched the surface (which means that even in German it's not easy to understand him :-(.

A final remark before turning back to physics: I admire the fathers of QM not only because they were able to figure out how to calculate atomic spectra etc., but because they were able to initiate a paradigm shift. Perhaps something like this is required today as well (we were happy with the standard model for some decades, therefore we still try to solve physical problems with the toolbox of the standard model ...). Reading Heisenberg or Schrödinger I heave the impression that they were educated and able to understand both - science and philosophy; the latter ability is missing today, at least partially (I do not know were it comes from; I have some ideas but it does not make sense to discuss in this thread).

Unfortunately I did not state my reasoning regarding Goedel carefully enough. Consistency is not the (core) issue, you are right. What I wanted to say is that during this discussion we try to develop a better understanding of what a ToE is and means and what the requirements, restriction etc. should be. I have the feeling that this is like a video game were you can enter the next stage but are immediately confronted with similar tasks, alien space ships etc. It's not really a new quality, is the same task with nastier enemies only. But you are never forced to leave the entire video game and cope with something totally new. So looking for physical theories is quite similar. You start with Newtonian mechanics, then Maxwell theory, then relativity, then quantum mechanics, etc. Even strings, holography etc. are no paradigm shift. If you are happy with this next stage everything is fine. This is like science works, it is successfull (for centuries!) - but we will never be able to leave the video game.

So this is my alternative 2) - we will never manage it; we will enter the next stage and after some decades ask ourselves "why green spacecrafts?" we will complete shooting all green alien spacecrafts, enter the next stage and find - red spacecrafts - ****!

Alternative 1) is to leave the entire game and find something totally different (a new game, all games at once, understand how video games are programmed, programm a video game generator, program a winning strategy generator, ...) Once we are able to specify what this means and how we can escape from the endless "next stage dilemma" the hole platonic world becomes directly visible to us, not only indirectly as in Platon's famous allegory of the cave. But this hole platonic world is rather closed to the idea of the MUH (mathematical universe hypothesis) discussed a couple of days or weeks ago.

99.9% percent of all scientists are working according to the "next stage model" - something we want to overcome - at least here in this thread :-). I do not have any idea how this could work (!) but alternative 1) seems to be as far-reaching as possible - even if I reasoned some time ago that I don't believe in it.

Don't get me wrong - a successful description of evolving physical laws, inference etc. is certainly more than just red spacecrafts. It's comparable to the revolution of quantum physics! So even if we see no hope in succeeding with 1) there is much sense in working on 2)

tom.stoer

Sep16-09, 10:16 AM

that's funny; I tried to post "s..." and it get's replaced ... works with "f..." as well :-)

RUTA

Sep16-09, 10:43 AM

Alternative 1) is to leave the entire game and find something totally different (a new game, all games at once, understand how video games are programmed, programm a video game generator, program a winning strategy generator, ...) Once we are able to specify what this means and how we can escape from the endless "next stage dilemma" the hole platonic world becomes directly visible to us, not only indirectly as in Platon's famous allegory of the cave. But this hole platonic world is rather closed to the idea of the MUH (mathematical universe hypothesis) discussed a couple of days or weeks ago.

99.9% percent of all scientists are working according to the "next stage model" - something we want to overcome - at least here in this thread :-). I do not have any idea how this could work (!) but alternative 1) seems to be as far-reaching as possible - even if I reasoned some time ago that I don't believe in it.

We avoid the dilemma of "the next stage model" because we admit a priori that the entire enterprise is one of self-consistency rather than fundamental laws governing the motion of fundamental entities in space as a function of time. Thus, the ultimate expression is not something “at the bottom,” begging for justification from something yet “deeper,” but a mathematical articulation of the self-consistency criterion for the process as a whole. It's a very different way of viewing the game itself, even though it's not a departure from the formalism per se (discrete path integrals a la quantum Regge calculus). Once you view the game differently, you begin to ask different questions of your formalism. Is that what you're talking about? If not, just ignore this post :smile:

friend

Sep16-09, 11:48 AM

We avoid the dilemma of "the next stage model" because we admit a priori that the entire enterprise is one of self-consistency rather than fundamental laws governing the motion of fundamental entities in space as a function of time.
...
but a mathematical articulation of the self-consistency criterion for the process as a whole...

The trouble we encounter is which set of consistent math describes physical properties. It seems we need to start with some physical properties and then try to discover a consistent math that describes it. This is the normal curve fitting techiques that science is acustomed to.

The only alternative is to trust with blind faith in consistency itself and see where it leads us. Then the question is how to translate this logical consistency between all facts into mathematical expressions. That seems like a tall order. I don't think we'd have much faith in such an effort until we could derive some familiar physical principles, like Fyenman's path integral or something. But once we started to get something that looks like physics, it would be hard to accept that it would not derive all of physics. Maybe it's worth a Google search to see if anyone has ever found "Physics derived from logic alone". I wonder if it's on the arXiv yet?

RUTA

Sep16-09, 12:11 PM

The trouble we encounter is which set of consistent math describes physical properties. It seems we need to start with some physical properties and then try to discover a consistent math that describe it. This is the normal curve fitting techiques that science is acustomed to.

The only alternative is to trust with blind faith in consistency itself and see where it leads us. Then the question is how to translate this logical consistency between all facts into mathematical expressions. That seems like a tall order. I don't think we'd have much faith in such an effort until we could derive some familiar physical principles, like Fyenman's path integral or something. But once we started to get something that looks like physics, it would hard to accept that it would not derive all of physics. Maybe it's worth a Google search to see if anyone has ever found "Physics derived from logic alone". I wonder if it's on the arXiv yet?

The self-consistency criterion (SCC) we propose is nothing so grand. Our SCC is just the discrete counterpart to the boundary of a boundary principle as used to construct the action for the transition amplitude. The form of the SCC survives the statistical limit and is responsible for classical field theory by construction. Roughly, we stick "boundary of a boundary is zero" in the bottom (so that it rules fundamental physics) in such a way that it is guaranteed to come out on top (survive the statistical limit and rule classical physics). Thus, on our view, the entire process of physics is one of self-consistency in this very specific (mathematically articulated) sense. See arXiv 0908.4348 for details. We shouldn't discuss this further here, but I would appreciate any comments, just send them to me directly via my PF profile.

tom.stoer

Sep16-09, 01:09 PM

friend

Sep16-09, 01:17 PM

This framework will (I guess) rich enough to contain at least logic and natural numbers, that means it will certainly have the Peano axoims as a subset. But then we know by Goedels theorem that it is
- either incomplete = not all true theorems are provable (*)
- or inconsistent = all theorems (true and false ones) are provable;

What does that mean when it is applied to a physical theory?

Physics is not the attempt to prove the completeness of math. No one expects to need every possible math statement to describe physics. In fact we are looking for a minimum set of equations that describe physics. We are looking for the overall, underlying principle from which all of physics is implied. This principle, by definitinon, would have to include all possible facts in the unverse so that it would be impossible to find exceptions. This suggests one underlying principle that all facts exist in conjunction, which means every fact is consistent with every other fact in the universe, so that every fact proves every other. The question is can you derive physical law from this principle?

RUTA

Sep16-09, 01:25 PM

I still do not understand the role of (self) consistency.

Let's assume a ToE is a mathematical framework, that means it consists of
1) basic rules (alphabet, ...) to define expressions
2) definitions, axioms
3) (derived) theorems = proofs according to 1+2)

This framework will (I guess) rich enough to contain at least logic and natural numbers, that means it will certainly have the Peano axoims as a subset. But then we know by Goedels theorem that it is
- either incomplete = not all true theorems are provable (*)
- or inconsistent = all theorems (true and false ones) are provable;
(*) one central theorem which is not provable is the consistency of the framework;
this last sentence has been proved by Goedel.

What does that mean when it is applied to a physical theory?

As friend said, physics isn't responsible for the self consistency of logic and math. The kind of self consistency we habor in physics is much less complicated. Einstein’s equations of general relativity (GR) provide an example. Momentum, force and energy all depend on spatiotemporal measurements (tacit or explicit), so the stress-energy tensor cannot be constructed without tacit or explicit knowledge of the spacetime metric (technically, the stress-energy tensor can be written as the functional derivative of the matter-energy Lagrangian with respect to the metric). But, if one wants a ‘dynamic’ spacetime in the parlance of GR, the spacetime metric must depend on the matter-energy distribution in spacetime. GR solves this dilemma by demanding the stress-energy tensor be ‘consistent’ with the spacetime metric per Einstein’s equations.

tom.stoer

Sep16-09, 02:06 PM

We avoid the dilemma of "the next stage model" because we admit a priori that the entire enterprise is one of self-consistency rather than ...

The trouble we encounter is which set of consistent math describes physical properties. ...

The only alternative is to trust with blind faith in consistency itself and see where it leads us. ...

Physics is not the attempt to prove the completeness of math.

I only wanted to stress that we cannot trust in consistency of theorems or math systems. Constructing a math system as a candidate-ToE automatically excludes the proof of its consistency.

That's why I am a bit more willing now to think about the idea that the ToE is not one single math system but the collection of all consistent systems.

RUTA

Sep16-09, 02:12 PM

I only wanted to stress that we cannot trust in consistency of theorems or math systems. Constructing a math system as a candidate-ToE automatically excludes the proof of its consistency.

That's why I am a bit more willing now to think about the idea that the ToE is not one single math system but the collection of all consistent systems.

That may be true for a Theory of Everything. Do you think physics alone can produce such a theory? It seems to be ruled out by virture of the fact that physics is concerned with the objective, not the subjective, so by its very nature any theory of physics cannot explain "everything."

friend

Sep16-09, 02:49 PM

That's why I am a bit more willing now to think about the idea that the ToE is not one single math system but the collection of all consistent systems.

A collection of consistent systems that are each consistent with every other should be regarded as one consistent system.

so by its very nature any theory of physics cannot explain "everything."

Are you suggesting that there are somethings that cannot be explained, that are illogical and deny all reason itself?

RUTA

Sep16-09, 03:07 PM

Are you suggesting that there are somethings that cannot be explained, that are illogical and deny all reason itself?

It may be true that some phenomena defy logic, but even if all phenomena are logical, I don't think physics can explain everything. As I argued previously, physics, as a system to explain the objective, cannot explain the subjective. Perhaps, you can appreciate my claim per the hard problem of consciousness.

Suppose we were able to explain all brain activity via physics (neurology and neurochemisty explained via physics). Using this you construct an explanation of what happens in the brain when a person sees the color red. You give this explanation to Alice who has never seen the color red, but she is very bright so she understands the explanation. You then show her something red. Does she have new knowledge after actually seeing red that she didn't possess prior thereto, even though she had and totally comprehended a complete physical explanation of seeing red? If you answer affirmatively, then you share my belief that physics cannot explain the subjective.

Similarly, Penrose claimed we cannot create a mathematical description of everything because part of everything is the recognition of the truth of a mathematical proof, which is itself beyond mathematics.

tom.stoer

Sep16-09, 04:08 PM

That may be true for a Theory of Everything. Do you think physics alone can produce such a theory? It seems to be ruled out by virture of the fact that physics is concerned with the objective, not the subjective, so by its very nature any theory of physics cannot explain "everything."
I don't think that physics alone (as it is understood today) is able. The question is what a ToE really IS. If you give me a set of equations and claim that this is the ToE, then what are good reasons for me to believe you?
That the theory makes physically correct predictions? The standard model would do the job!
That it explains some (all) free parameters? OK, let's assume string theory eventually provides a selection principle which essentially predicts U(1)*SU(2)*SU(3) + three generations; Of course my next question would be: why strings?
That it is consistent (whatever that means)? We believe that the standard model plus gravity is somehow inconsistent, but as I said we will never be able (for no complex mathematical framework) toprove its consistency.

What we are talking about is more than a ToE with a set of equations, rules etc. which is (as Marcus said) predictive up to arbitrary high energies. It is a kind of meta-theory that provides in some sense a good reasoning why it is the way it is. And I think it's exactly this question we are not able to answer.

tom.stoer

Sep16-09, 04:20 PM

A collection of consistent systems that are each consistent with every other should be regarded as one consistent system.
Of course it only makes sense to distinguish between two systems if they are either independet from each other or inconsistent with one another

Is [set theory with continuum hypothesis] and [set theory with the negation of the continuum hypothesis] one system? I do not know if a ToE requires a specific choice for the continuum hypothesis; but if it does, we have to ask what about a different ToE were "somebody" made a different choice.

The continuum hypothesis may be artifical, but homeomorphic, non-diffeomorphic manifolds may very well be physically interesting!

tom.stoer

Sep16-09, 04:27 PM

... I don't think physics can explain everything.

Similarly, Penrose claimed we cannot create a mathematical description of everything because part of everything is the recognition of the truth of a mathematical proof, which is itself beyond mathematics.
This seems to be very reasonable and indicates that physics is limited in its explanatory ability.

But - isn't it possible to transcend this reasoning? Let's assume that the only requirement for a ToE in a mathematical multiverse is that the ToE must be consistent. Of course one cannot proof consistency of the theory, but one can claim (in a platonic sense) that one specific theory either IS consistent or it is NOT (just like any natural number either IS prime or it is NOT prime, regardless if we already checked it). If we do that we reduce all theories to a subset, namely the consistent theories.

RUTA

Sep16-09, 06:36 PM

This seems to be very reasonable and indicates that physics is limited in its explanatory ability.

But - isn't it possible to transcend this reasoning? Let's assume that the only requirement for a ToE in a mathematical multiverse is that the ToE must be consistent. Of course one cannot proof consistency of the theory, but one can claim (in a platonic sense) that one specific theory either IS consistent or it is NOT (just like any natural number either IS prime or it is NOT prime, regardless if we already checked it). If we do that we reduce all theories to a subset, namely the consistent theories.

Of course, if what you mean by "everything" is restricted to a small enough domain of discourse, you can get a ToE in any context! I'm a physicist working on the unification of physics, so mine is purely self criticism here. It's ridiculous to think physics is the be-all end-all of knowledge and reason.

BigFairy

Sep17-09, 03:25 AM

Of course, if what you mean by "everything" is restricted to a small enough domain of discourse, you can get a ToE in any context! I'm a physicist working on the unification of physics, so mine is purely self criticism here. It's ridiculous to think physics is the be-all end-all of knowledge and reason.

Oh? i would beg otherwise..

moniker2

Sep17-09, 06:47 AM

Of course it only makes sense to distinguish between two systems if they are either independet from each other or inconsistent with one another

Is [set theory with continuum hypothesis] and [set theory with the negation of the continuum hypothesis] one system? I do not know if a ToE requires a specific choice for the continuum hypothesis; but if it does, we have to ask what about a different ToE were "somebody" made a different choice.

The continuum hypothesis may be artifical, but homeomorphic, non-diffeomorphic manifolds may very well be physically interesting!

I have seen something like that before, around two years ago. I posted here and was called a crackpot and banned.

Fra

Sep17-09, 07:25 AM

FWIW - here is some more fuel on the fire.

About this discussions about deductive systems of inference and consistency and how it relates to physics, I think there are different ways to view the relation between physics and logic, but I'll just trow in these reflections.

From my point of view of physical law, and physical action as pretty much one to one with an inference system, I see some analogies that I can related to, but I think in terms of inductive inference and actions beein constrained by the inference system, and feedback from the environment to change the inference system.

This Gödel stuff is quite different in that it applies to deductive systems of inference, which from my point of view makes no sense in physics for the very reason that I think that if you take the inference seriously, then even the inference system itself must be inferred, which effectively measn that even for the special case of deductive systems, the axioms are not chosen at will, they are the result of an inference process. But not a deductive one.

The consistency I would personally usually make sense of in physics, is just that if we see the laws of physics as a system of inference (whereby initial conditions implies the future) then consistency would normally mean that different observers should arrive at the "same future", or alternatively that different observers making an inference/abduction of laws from experience they would end up with the same laws of physics.

However, for various reasons I do not think that there is any meaning in that because such consistency is not inferrable from the point of view of an inside observer. To me this is largely intuitive, but there are also some other arguments. This is maybe vaguely similar to gödels incompleteness theorem, but still not quite of course.

Anway, Instead, my view is that inconsistencies in the above sense might actually occur, but observation of those inconsistencies is exactly what causes evolution or defomration of the inference system as represented by a physical observer.

So instead of thinking that physics is a system of consistent "inference systems", I personally think of it as systems of *interacting* inference systems, and interaction terms can sort of be traced to partial inconsistencies between the actions/inference systems of the interacting observers.

Because I do not think in terms of deductive inference, but rather inductive inference, the "inconsistencies" are not truly the kind of thing that crashes the logical system, instead the inconsistency produces a "negative" feedback that will decrease the confidence in the inconsisntent inference system, which will instead evolving to something MORE consisntent, but not necessarily perfectly so.

/Fredrik

Fra

Sep17-09, 07:43 AM

then consistency would normally mean that different observers should arrive at the "same future", or alternatively that different observers making an inference/abduction of laws from experience they would end up with the same laws of physics.

the trick I envison to make sense out of this: Almost needless to say, the futures we are talking about here are not actual futures, it's only the INFERRED future, based on whatever incomplete premises and imperfect inference system at hand, and the only FUNCTION of this inferred future is that it impacts the ACTION of the inference system itsef.

Just like the behaviour of the human, depends on what expectations of the future the brain has; the action is clearly invariant with regards to the ACTUAL future. In reality, the inferece systems itself is update during the evolution; not just jumping from initial to final state.

Thus, in this view I think it's crystal clear that this is not a true contradiction - it is rather the basis for an interaction.

One might ask why can't this defined by the class of "disagreements", is well defined and can be treated like we usually do on physics with gauge symmetries and gauge interactions and thus this transformation IS then the REAL law that is invariant, and thus restores consistency.

I think the problem with this "resolution" is that it isn't realisable, when you acknolwedge that the information required to actuall infere the symmetry, is not localised to ONE observer, it's an entire local population of observers. But this is also why this scheme DOES make sense when you study a confined subsystem; like is the case in particle experiments. but this is not equally obvious when you consider how a particle experiences it's own environment, or how things behave very very far from equilibrium. Such as the big band or other hypotetical scenarios. This scheme is also (IMHO at least) quote doubtful for cosmological thinking.

/Fredrik

ConradDJ

Sep17-09, 08:37 AM

The question is what a ToE really IS. If you give me a set of equations and claim that this is the ToE, then what are good reasons for me to believe you?
That the theory makes physically correct predictions? The standard model would do the job!

What we are talking about is more than a ToE with a set of equations, rules etc. which is (as Marcus said) predictive up to arbitrary high energies. It is a kind of meta-theory that provides in some sense a good reasoning why it is the way it is. And I think it's exactly this question we are not able to answer.

Physics has never been concerned to answer "why it is the way it is." But I agree it's become important to ask this question now. It's certainly possible that the LHC will uncover phenomena that once again point theorists in a new direction. And it's possible that technical developments in quantum gravity will come up with something that seems compelling. But to me it's amazing how much is known about fundamental physics, and how little we've been able to learn from that vast body of knowledge, about what's going on here.

In biology, the question "why things are the way they are" has a remarkably clear answer, that provides a foundation for the entire field. It's not unreasonable to expect something similar in physics.

My own sense is that whatever's going on in physics is not just mathematical. If we just regard the world as a pattern of given facts, we can try to model it mathematically -- and this has essentially been accomplished, with the Standard Model. We can push on in the direction of Unification... but is there really any deep basis for our belief that the world must be built on a single structure? Once we get beneath the atomic level, is there really any empirical support for this? For every step toward unification, we've opened up new kinds of differences between fundamental structures.

But the thing is, our world is much more than a body of fact. Among other things, it's a system that makes its facts physically meaningful -- i.e. observable and definable in terms of other facts, that are also physically observable and definable.

Mathematical systems seem to work very differently -- they're logical structures built on undefined basic elements / operations. These basic elements are meaningful to us, because we live in a physical world that has analogues to them. But there seem to be very basic features of the physical world that we haven't yet tried to account for in our theoretical models.

tom.stoer

Sep17-09, 03:31 PM

I have seen something like that before, around two years ago. I posted here and was called a crackpot and banned.

Dear friend,

let's wait and see what will happen to me :-)

btw - a few days ago a got a hint to read the following paper:

http://arxiv.org/abs/gr-qc/0404088
Quantum general relativity and the classification of smooth manifolds
Hendryk Pfeiffer
(Submitted on 21 Apr 2004 (v1), last revised 17 May 2004 (this version, v2))
Abstract: The gauge symmetry of classical general relativity under space-time diffeomorphisms implies that any path integral quantization which can be interpreted as a sum over space-time geometries, gives rise to a formal invariant of smooth manifolds. This is an opportunity to review results on the classification of smooth, piecewise-linear and topological manifolds. It turns out that differential topology distinguishes the space-time dimension d=3+1 from any other lower or higher dimension and relates the sought-after path integral quantization of general relativity in d=3+1 with an open problem in topology, namely to construct non-trivial invariants of smooth manifolds using their piecewise-linear structure. In any dimension d<=5+1, the classification results provide us with triangulations of space-time which are not merely approximations nor introduce any physical cut-off, but which rather capture the full information about smooth manifolds up to diffeomorphism. Conditions on refinements of these triangulations reveal what replaces block-spin renormalization group transformations in theories with dynamical geometry. The classification results finally suggest that it is space-time dimension rather than absence of gravitons that renders pure gravity in d=2+1 a `topological' theory.

Tom
(on behalf of all crackpots)

MTd2

Sep17-09, 03:35 PM

Hey Tom, I didn't you also liked exotic smoothness. Right?

tom.stoer

Sep17-09, 03:56 PM

FWIW - here is some more fuel on the fire.

... the "inconsistencies" are not truly the kind of thing that crashes the logical system, instead the inconsistency produces a "negative" feedback that will decrease the confidence in the inconsisntent inference system, which will instead evolving to something MORE consisntent, but not necessarily perfectly so.

Honestly speaking I expected something like that!

I came to the conclusion that insisting on inference and at the same time relying on axiomatic methods would cause big trouble for you approach. It would rely on consistency w/o being able to prove or disprove it. Every question for consistency or completeness would force you to enter the next stage where you eventually face the same kind of problems.

So it seems like a clearance to change the perspective and let the hole thing become subject to evolution w/o ever referring to "something" fixed. I was thinking about consistency being the only selection criterion, but I couldn't make sense out of it because in any axiomatic approach inconsistency is not something you can deal with - you must simply throw it away.

I still see problems with that approach:
1) I still have the feeling that there is "something" in your approach that is NOT subject to evolution and that is NOT immune regarding the following argument:
2) I think that you can change perspective again and map your approach into a kind of axiomatic system or a member of a family of axiomatic systems.
3) Then you are trapped again because now you have to deal with inconsistent axiomatic systems - not a very nice idea.

But I should stress that this is perhaps not the problem of your approach but only my problem in understanding it (or being able to attack my own prejudices).

tom.stoer

Sep17-09, 04:21 PM

Physics has never been concerned to answer "why it is the way it is."
I disagree. I think these kind of questions are the very driving force for the progress of science over centuries! I think latest since the early days of quantum mechanics every day physics is concerned with questions regarding measurements and predictions, but every revolution in science has its roots in questions like "why is ...". Nobody was able to present a full answer, only approximations to some deeper truth, so perhaps that's why we are not used to ask and analyze these questions.
In addition certain philosophers claimed that those questions are meaningless and must be avoided in all sound systems - which is a reasoning we know from "The Fox and the Grapes".

But to me it's amazing how much is known about fundamental physics, and how little we've been able to learn from that vast body of knowledge, about what's going on here.

Good point! I think Smolin was pointing out that for a further development of quantum gravity, unification etc. we do not necessarily have to wait for new experimental results. Let me explain why: Progress in physics was always a step-wise approach. First there were experimental results w/o a theoretical explanation. Then there was a theory able to post-dict these phenomena - and to predict new ones. Today we are confronted with a couple of phenomena (4-dim. spacetime, dark energy, U(1)*SU(2)*SU(3), three generations, ...) we do not understand and we cannot explain (why spacetime is four-dimensional is a very good question even w/o referring to string theory). So the very first step for a candidate ToE need not be to predict new phenomena but to post-dict the known ones!

But there seem to be very basic features of the physical world that we haven't yet tried to account for in our theoretical models.

Can you give me examples?

tom.stoer

Sep17-09, 04:22 PM

Hey Tom, I didn't you also liked exotic smoothness. Right?

What do you mean exactly?

MTd2

Sep17-09, 07:00 PM

What do you mean exactly?

You said "The continuum hypothesis may be artifical, but homeomorphic, non-diffeomorphic manifolds may very well be physically interesting!"

In 4 dimensions, that is exotic smoothness. Google for it! :) This is the topic that I like the most, and I think it is at the very core of every 4 dimensional theory with fractal dimensions, like Horava gravity, LQG, Loll's universe, Asymptotic Safety, and the likes.

This is also closely relateted to the classificantion of smooth 4-dimensional manifolds. The simple connected case has not classification, and it is also related to the question if the generalized poincare conjecture is true or not in 4 dimensions. That is, about the existence of exotic smooth sphere. Hendryk Pfeiffer paper above is related to all this.

RUTA

Sep17-09, 09:27 PM

To repeat Dicke's famous response, "Well boys, we've been scooped." The search for the unified force is over:

http://www.theonion.com/content/node/39512

Damn, I had my money on LQG.

Fra

Sep18-09, 12:35 AM

Honestly speaking I expected something like that!

I came to the conclusion that insisting on inference and at the same time relying on axiomatic methods would cause big trouble for you approach. It would rely on consistency w/o being able to prove or disprove it.

I think you are starting to see the logic I tried to convey.

I still see problems with that approach:
1) I still have the feeling that there is "something" in your approach that is NOT subject to evolution and that is NOT immune regarding the following argument:
2) I think that you can change perspective again and map your approach into a kind of axiomatic system or a member of a family of axiomatic systems.
3) Then you are trapped again because now you have to deal with inconsistent axiomatic systems - not a very nice idea.

I guess it is possible to try to map this into a kind of sujbective axiomatic approach, but then to keep the spirit, the set of subjective axioms would sort of constitute the DNA of the inference system, and those actual systems encoding in their actions a particular inference system, would still be subject to challange/selection, and one could say that the inference system implicit in a set of axioms, can have varying degrees of "success" of actually making inferences that MATCH the actual future, and here there is a selection for the axioms, so that axioms can be lost, like genes can be lost, and new axioms can come.

So if we insiste on a axiomatic approach, and still insist on keeping the spirit of reasoning here, then the axioms are still subject to evolution. One one is faced with the problem of understand the logic behind going from axiomatic system to another.

That might make sense to me, but it doesn't make the problem easier, it's just putting it in different words. IT's still very different from the ordinary axiomatic approach, which is more like an accumulative buildup of an axiomatic system. This does not match what I envision because the "choice of axioms actually contains information" about what's fit and what's not. And the axiomatic system are still bounded in complexity in my view, since it's encoded by a finite inside observer.

So the really ordinary axiomatic method (without this evolving stuff I talk about) does not as I see it match this.

/Fredrik

tom.stoer

Sep18-09, 02:26 AM

In 4 dimensions, that is exotic smoothness. Google for it! :) This is the topic that I like the most, and I think it is at the very core of every 4 dimensional theory with fractal dimensions, like Horava gravity, LQG, Loll's universe, Asymptotic Safety, and the likes.

This is also closely relateted to the classificantion of smooth 4-dimensional manifolds. The simple connected case has not classification, and it is also related to the question if the generalized poincare conjecture is true or not in 4 dimensions. That is, about the existence of exotic smooth sphere. Hendryk Pfeiffer paper above is related to all this.

Yes, you are right, this is exactly what I am talking about. The paper provides a fresh view on PL manifolds which could be used as "diffeomorphims-invariant triangulation". This is a very interesting idea.

I am not so sure if exotic smoothness for R^4 is the very core of 4 dim. physics. Pfeiffer explicitly excludes topologogically inequivalent manifolds, but I would expect that different topologies will matter as well. (I've seen some statements in this regard in the CDT context, but I can't remember the details ...)

tom.stoer

Sep18-09, 02:40 AM

I guess it is possible to try to map this into a kind of sujbective axiomatic approach, ... ... and here there is a selection for the axioms, so that axioms can be lost, like genes can be lost, and new axioms can come.

So if we insiste on a axiomatic approach, and still insist on keeping the spirit of reasoning here, then the axioms are still subject to evolution. One one is faced with the problem of understand the logic behind going from axiomatic system to another.

That might make sense to me, but it doesn't make the problem easier, it's just putting it in different words. ...

No, it's not just putting it in different words.

1) If you succeed with this reformulation you will have an axiomatic approach which describes how axiomatic systems can evolve. It describes (sets the rules) how axioms can be lost and how one can go from one axiomatic system to another. It will be very interesting to learn if this meta-level is again an axiomatic system, if it is subject to evolution, if it can be constructed explicitly or if you can only prove existence, what about my "next stage ..." reasoning etc.

2) If you fail you will hopefully learn from failing if your approach is richer than the purely axiomatic one; perhaps failing with the construction will be a success for your approach ...

So you will learn if your approach is immune to my criticism - and if this is a feature or a weakness (weakness in the sense that self-immunization may be non-scientific; refer to arguments against the anthropic principle).

Fra

Sep18-09, 03:38 AM

No, it's not just putting it in different words.

1) If you succeed with this reformulation you will have an axiomatic approach which describes how axiomatic systems can evolve. It describes (sets the rules) how axioms can be lost and how one can go from one axiomatic system to another. It will be very interesting to learn if this meta-level is again an axiomatic system, if it is subject to evolution, if it can be constructed explicitly or if you can only prove existence, what about my "next stage ..." reasoning etc.

2) If you fail you will hopefully learn from failing if your approach is richer than the purely axiomatic one; perhaps failing with the construction will be a success for your approach ...

So you will learn if your approach is immune to my criticism - and if this is a feature or a weakness (weakness in the sense that self-immunization may be non-scientific; refer to arguments against the anthropic principle).

I thikn I see what you mean.

Do you mean wether it's possible to describe what I propose - the evolving axiom system - again as a *fixed* objective larger axiom system?

I think that is not possible - it would in fact not be very conceptually consistent with the spirit of the idea. What I think is possible OTOH, which also part of the idea here, is that it IS possible to describe the evolution of axiom systems, RELATIVE to another axiomsystem. But there is no objective universal axiomsystem which we can see in a realist view.

I figure you also think it's weird that if there are no objective, or non evolving structure, how can this possibly get predictive? The idea is that I view this as a game, and all we can do is play.

One might compare this again to Gödel stuff in that the consistency of one system could be provable from another axiom system (normally larger), and the correspondence of this in my view would be how one observer inferes the action of parts of it's environment.

But there is as far as I have analyzed this, always more questions that you CAN NOT answer, but you can insist on asking them - this is in my mind related to evolution and also at a different level in the hierarcy time.

/Fredrik

Fra

Sep18-09, 04:25 AM

It will be very interesting to learn if this meta-level is again an axiomatic system, if it is subject to evolution, if it can be constructed explicitly or if you can only prove existence, what about my "next stage ..." reasoning etc.

I'm not sure my response made sense to you but what I mean to say, is that to predict one axiomatic system or inference system, you need another inference system. (observer2 observes observer1) This could I think probably we realised at least effectively if we consider the inference system we discuss when we do particle physics. Because then we can make inferences of this inference system, relative to the environment which in a way is a much larger inference system.

This is I think possible, but the larger context is itself evolving, and there simply is no external axiom system, much like there is no external space which the universe is expanding INTO. Neither do I think there is an objective configuration space for the universe which describes multiverses.

That's quite analogous to the problem of inference systems.

I THINK you are wondering if what I suggest can be phrased in terms of a possible larger fixed axiomatic system that plays the rold of meta law. If so, I do not think that so, and neither do I at least see it as a problem. It's probably the natural way you'd want to see it, when coming from the traditional view: To try to axiomatise, the axiom evolution, or to describe the evolution by law by a meta law. This is not how I see it. But like I tried to convey, there ONE correspondence to "meta law" I do see, is still constrained to an inside view which is usually bounded (the size of the genome is bounded), there is no external context where it can be, unless you do take on a structural realist view, THEN it makes sense, but I don't. And it also introduces an enourmous ambiouity - massive landscape of possible "master inference systems". And I think others have made that mistake before, and I don't intend to repeat it :)

/Fredrik

tom.stoer

Sep18-09, 05:03 AM

Do you mean wether it's possible to describe what I propose - the evolving axiom system - again as a *fixed* objective larger axiom system?

I think that is not possible - it would in fact not be very conceptually consistent with the spirit of the idea.
Yes. I am not convinced that your approach is right, but IF it is right, this must be true, of course.

What I think is possible OTOH, which also part of the idea here, is that it IS possible to describe the evolution of axiom systems, RELATIVE to another axiomsystem. But there is no objective universal axiomsystem which we can see in a realist view.
Again my question is how these laws of evolution become subject to evolution.

Let me present you one argumentation which demonstrates why and how your approach will fail - or at least why you fail in explaining it to us:

Assume for a moment that you were able to figure out how it works, that you were able to explain in detail and that finally we all agree. Wouldn't that mean that your approach became a somehow fixed system of rules and statements? Wouldn't that mean that it is no longer subject to evolution? Wouldn't that mean that your meta-program became an "axiomatic system"?

If you have to admit that the answer is "yes", there are two possible conclusions:
If you accept this reasoning, you have to admit that your approach has failed.
If you insist on the success of your program the only way out is to accept that you will never be able to figure it out completely and explain it to us.

If you say that the answer to the above raised questions is "no" there is only one conclusion, namely that the approach is somehow inconsistent or incomplete as we agreed to accept it,but at the same time we concluded (right now!) that it is not fixed but subject to change and therefore we have to withdraw our acceptance unless you have finished your work.

A last way out would of course be to abandon the theory (at least partially) and admit that the theory itself is immune to this discussion - or that these self-referential constructions must be excluded due to consistency. But that of course means that it's no longer a ToE but that its domain of application is in some sense limited.

Fra

Sep18-09, 06:25 AM

I see and acknowledge your question. I've certainly thought about this but I need to think a bit on how to phrase it to be more clear. Part of the ambigouity is that this is my own reasoning ie. it's subjective. So this is indeed only as per my own inference system and "educated guess".

Am I CERTAIN that this program will succed? Of couse not! But - here is my subjective basis - I see NO better option. It's the most plausible idea I have. If you have a better one and are able to convince me, I am open.

Similarly, I fully understand that it's not trivial to convey and abstract idea to anyone else. I do not expect you to easily get it. This is why like I said before, the ultimatey argument will be if and when I succeed. But most probably the first publication will not be on here :)

But for sure the argument I present now and here are not meant to be definitive arguments at all for my approach. It is only plausible arguments as part of a sound discussion.

I'll see how I can make this clearer, but I apparently need a different way to putting.

More later

/Fredrik

ConradDJ

Sep18-09, 07:20 AM

But the thing is, our world is much more than a body of fact. Among other things, it's a system that makes its facts physically meaningful -- i.e. observable and definable in terms of other facts, that are also physically observable and definable.

Mathematical systems seem to work very differently -- they're logical structures built on undefined basic elements / operations. These basic elements are meaningful to us, because we live in a physical world that has analogues to them. But there seem to be very basic features of the physical world that we haven't yet tried to account for in our theoretical models.

Can you give me examples?

Yes... the key example is just this business of measurement. If you have a physical fact -- say the mass of a particle -- there is also a physical context of interaction that allows its measurement. This context involves other kinds of physical facts -- to observe the mass of a particle, you need to be able to measure space/time intervals, etc. Another way to describe this: the world is not only a set of facts, but is also a system that physically communicates those facts... by means of other kinds of facts, that are observable in the context of other facts. Our current theories aim to be mathematical models of the fact-structure, but I don’t know of anything that models the structure of the communications system.

I tried to describe this kind of functionality in another thread –
http://www.physicsforums.com/showthread.php?t=332292

But there are other “basic features of the physical world” that – so far as I know – haven’t been modeled mathematically. Our laws of physics obviously support more or less stable structures – atoms and molecules, crystals, all kinds of material objects. How does this work? It all depends on the functionality of the basic “building-blocks” – but atomic structure is very complicated, dependent on several apparently unrelated principles, e.g. electromagnetism, the exclusion principle, and whatever the laws are that keep nuclear particles stable.

So our world clearly provides highly functional “building-blocks” – but is there a theory that tries to explain what kinds of physical principles are required to do this?

Then too there’s the “calculation problem”. Obviously, in our world, physical systems obey dynamic laws, to a remarkable degree of precision. Yet we know that even in such a simple case as Newtonian gravitational dynamics among three point-particles, the equations have no analytic solution. Very clearly, physical systems do not have to compute their dynamics... so how does this thing of “obeying laws of physics” actually work? How does the physical world constantly create precise real-time “solutions” to problems that are mathematically intractable?

Basically I’m responding to your idea that we need a radical new paradigm, by saying – there are basic things we take for granted about the physical world, that haven’t yet been addressed in physical theory. If you’re taking seriously the question – why are things the way they are? – maybe these other aspects of “how things are” need to be considered, to get the complete picture.

MTd2

Sep18-09, 07:43 AM

I am not so sure if exotic smoothness for R^4 is the very core of 4 dim. physics. Pfeiffer explicitly excludes topologogically inequivalent manifolds, but I would expect that different topologies will matter as well. (I've seen some statements in this regard in the CDT context, but I can't remember the details ...)

Exotic smoothness exists for an infinite type of different topologies! What I said about exotic sphere it is that it is the most difficult one is the the one case in which there is homomorphism to a sphere, thus, an exotic sphere. There are exotic spheres in several dimensions, but in 4 dimensions it is unkown. But if there is, it will be one that has infinite non-diffeomorphic kinds. In other dimensions, the number is merely finite.

tom.stoer

Sep18-09, 11:16 AM

Exotic smoothness exists for an infinite type of different topologies!

All I wanted to say is that before different differential structures for one fixed topology become interesting, different topologies will be important. Look at strings: there you do not have several differential structures but its the basic topology of the world sheet that matters.

But I agree, exotic smoothness is a fascinating discovery.

tom.stoer

Sep18-09, 12:39 PM

I see NO better option. ... If you have a better one and are able to convince me, I am open.

I certainly do not have a better one :-)

I am still thinking about the (ontological) relation between mathematical structures and physical entities. I am thinking about criteria for a candidate-ToE. I would say that a rather direct relation between mathematics and physics is obvious - otherwise it's magic why mathematics describes our world in a very accurate way. But I am not willing to accept that mathematics IS reality = IS physics.

Mathematics cannot answer questions regarding existence. THINKING about new axioms for set theory in order to overcome the axiom of choice and the riddle regarding the continuum hypothesis is neither equivalent to CREATING corresponding universes nor is it equivalent to DISCOVERING these (already existing) universes. Therefore there is a missing link between physical existence and mathematical truth.

I am still more conservative in the sense that I believe in rather fixed physical laws which do not change in time or which emerge from a deeper structure. If the latter would be true I would immediately try to get hands on this deeper (but then again fixed) structure and take this as a more fundamental law. And I am conservatice in the sense that I do not like anthropic reasoning as it seems to me to be a collection of excuses only.

Later I will try to explain in more detail how my proposal could look like. Unfortunately currently I am only able to tell you how it does NOT look like.

MTd2

Sep18-09, 01:36 PM

Look at strings: there you do not have several differential structures but its the basic topology of the world sheet that matters.

You do have exotic structures in string theory. Actualy, Witten was the first one to write about exotic structures, although in 8 dimensions.

http://math.ucr.edu/home/baez//week141.html

Edward Witten, Global gravitational anomalies, Commun. Math. Phys. 100 (1985), 197-229.

http://projecteuclid.org/DPubS?service=UI&version=1.0&verb=Display&handle=euclid.cmp/1103943444

But I rather study the most complex ones, infinitely more, which are in 4 dimensions, and it also happens to be the dimension we live in.

Fra

Sep18-09, 05:12 PM

Wouldn't that mean that your approach became a somehow fixed system of rules and statements? Wouldn't that mean that it is no longer subject to evolution? Wouldn't that mean that your meta-program became an "axiomatic system"?
...
If you say that the answer to the above raised questions is "no" there is only one conclusion, namely that the approach is somehow inconsistent or incomplete as we agreed to accept it,but at the same time we concluded (right now!) that it is not fixed but subject to change and therefore we have to withdraw our acceptance unless you have finished your work.

My answer to the above would be the no option.

I follow your reasoning but I think your expected logic is too rigid to be fit for the quest we face, and I think the explanation might be a difference in focus here. I used to think like that - I didn't always like the concept of evolving law - but I changed my mind. I think your rigid thinking is connected to your "traditional view" of fixed laws, that's how it was for me. But the more I thought about this the more did I see that this really isn't what I see, it was just what I expected to see.

So what is the problem at hand? To find and capture the TOE? No, not in my mind. The problem is that we want to increase our understanding as much as possible as fast as possible as rational as possible. the point is that even if a TOE is a goal, the ROAD to the TOE is the more immediate goal. Thus the goal is to infere the immediate future, not the end of time. And by construction then the inference system is present "now", is different from the one present in a definite future.

At no point in this process, must the fact that we are still on a journey, or the fact that our inference system can improve, inhibit us from actually doing so. I have a feeling thta your quest for "perfection" or ultimate consistency, ambitious as it may be, is actually inhibiting. You almost run into a halt. Nature don't do that. I'm just projecting here my own path from where I was to where I am. But my hat would go off if you can capture the perfect eternal consistency between the palms of your hans, but I couldn't do it, and I don't see how it would even make sense. My attempt of TRYING, lead to my my current strategy. So I did consider the rigid inference system, but I can't make sense out of it. Thereof my position.

I'm repeating myself here but I think your resistance against accepting evolving inference systems as an actual best descriptio nof nature (rather than a fixed on) is similar to Einsteins original resistance against the evolving/expanding universe. At first he tried to make it static, because he didn't first know that the universe ISN'T static.

Look around, does the inference systems we can distinguish in nature seem fixed? Not as far as I can see.

/Fredrik

friend

Sep18-09, 06:31 PM

Mathematics cannot answer questions regarding existence. .....Therefore there is a missing link between physical existence and mathematical truth.

The only representation we have of the states of existence or non-existence is binary logic with its algebric manipulation of true and false. Here true represents what exists, and false represents what does not exist. We always consider true those statements that describe what really is, and visa versa. So any ToE that proports to determine what is, as opposed to what is not, would have to be based in logic. Can you imagine a theory of physics which does not comply with logic? I think logic is a ToE since we assume it applies to everything physical. The question is how do we extract laws of physics from this.

It may not be that hard. Whatever the tiniest constituents of reality are, it's fair to assume they can be describe with statements or propositions. And it's fair to assume that every little part co-exists with every other little part. That means reality is described as a logical conjuntion of all the propositions for every little part. I would assume that there is an infinite number of porposition required to describe all of reality. And in order to distinguish each little part, every proposition would have to be assigned numbers, or coordinates to keep track of them.

Any mathematical law of physics by definition has to describe how things go from one state to the next, how one set of propositions necessarily implies the next. These laws, like any function, describe how given one state what the next state will be, and given that what the next state will be, and given that what the next will be, etc. We could use a variable, say, t, to parameterize which step along the path you're at. And since all the facts co-exist together, there is no prefered path in the way one proposition implies the next, and every path would have to be considered. So maybe this conjunction of propositions can be manipulated into a combination of paths of implication and somehow integrated using the assigned coordinates to give us something that looks like a physical law, say something like Feynman's path integral or something.

tom.stoer

Sep19-09, 02:00 AM

My answer to the above would be the no option.

At no point in this process, must the fact that we are still on a journey, or the fact that our inference system can improve, inhibit us from actually doing so.

OK, now you position is clear. You include in the process not only nature's evolution of laws but also our quest for these laws. My feeling as that it becomes al little too subjective, but that's my position - and I don't want to repeat it here.

I have a feeling thta your quest for "perfection" or ultimate consistency, ambitious as it may be, is actually inhibiting. You almost run into a halt. Nature don't do that. ... My attempt of TRYING, lead to my my current strategy. So I did consider the rigid inference system, but I can't make sense out of it. Thereof my position.

Yes, you are right. As I just said I can only tell you how it does NOT work (what a pitty). If it is this what you mean by "halting" then I agree.

Looking at the dilemma we face, there are two very different options.

You have chosen to search for evolving laws - and you somehow adapt your search strategy accordingly. You are like Achilles running after the turtle. You never overtake the turtle, but you are coming closer and closer - and perhaps this is the best you can do.

I have chosen (together with other traditionalists) to look for deeper levels of understanding and laws. It's a layer model, where uncovering the next layer immediately raises new questions. Here it doesn't matter if the layers are fixed and static or if they are evolving, because in this picture the laws for evolution would somehow be located at the next layer, so it fits into the picture.

If we focus in your picture more on the process of science, then we more or less agree; it's just a special description of philosophy of science. My new layers are paradigm shifts or revolutions (I think Kuhn wrote something like that).

If we focus on the nature and existence (or emerence) of laws then we disagree - but that's the interesting point here :-)

tom.stoer

Sep19-09, 02:20 AM

The only representation we have of the states of existence or non-existence is binary logic with its algebric manipulation of true and false. Here true represents what exists, and false represents what does not exist. We always consider true those statements that describe what really is, and visa versa.

I agree to one part of the statement: 1) Everything that EXISTS must respect some laws of (binary???) logic and therefore correpsonds to some consistent mathematical system. But the other way round it's deep philosopophical statemet which I cannot accept w/o further discussion: 2) EVERY sound mathematical (logical) system EXISTS.
(I hope that is the meaning of your "vice versa")

[QUOTE=friend;2355377]So any ToE that proports to determine what is, as opposed to what is not, would have to be based in logic. Can you imagine a theory of physics which does not comply with logic? I think logic is a ToE since we assume it applies to everything physical. The question is how do we extract laws of physics from this.[/QUOTE

Very good starting point.

[QUOTE=friend;2355377]... every proposition would have to be assigned numbers, or coordinates to keep track of them.[/QUOTE

Then you face the usual trouble with natural numbers, Gödel etc. Binary logic alone seems to not powerfull enough to do the job; using natural numbers may lead to inconsistent or incomplete systems w/o any chance to prove or disprove it.

Let me ask some questions to get a better understanding of your second statement:

Do you believe that natural numbers exist?

Do you believe that this is not only a platonic existence, but that there is a level of mathematics (say the natural numbers) that IS physically EXISTING = fundamental physical entities (which we haven't discovered so far).

Do you believe that you can somehow construct physical laws (which rely on more than logic) from logic itself? That means do you think that natural numbers, real numbers etc. emergy somehow from logic alone?

Or do you think that if we uncover the ultimate laws of science those concepts fade away as purely approximate descriptions and we are faced with a system of logical automata interacting with each other?

ConradDJ

Sep19-09, 07:22 AM

The only representation we have of the states of existence or non-existence is binary logic with its algebric manipulation of true and false. Here true represents what exists, and false represents what does not exist... So any ToE that proports to determine what is, as opposed to what is not, would have to be based in logic... I think logic is a ToE since we assume it applies to everything physical. The question is how do we extract laws of physics from this.

It may not be that hard. Whatever the tiniest constituents of reality are, it's fair to assume they can be describe with statements or propositions...

Friend -- The point I was trying to make above (#149, 186) is that this binary representation of physical existence isn’t adequate. For a proposition “A exists” to have any meaning, it must be possible for something to determine something about A through interaction, within some particular frame of reference.

The very essence of classical physics is the assumption that these conditions under which something can be meaningfully determined have nothing to do with the nature of physical existence itself – a thing “just is” what it is, regardless of the conditions under which it can make a difference to anything else in the world. The essence of QM is the discovery that this is not the case.

Likewise the logical proposition “A=A” is fine, but has meaning only insofar as you can actually identify a determinate “A” and distinguish it from and compare it with other things. Because our physical universe gives us many, many ways of doing this, logic seems to apply to everything, as you say, a priori.

But again, the classical assumption is being made that the functionality that lets the existence of things be physically meaningful to each other, is irrelevant... that is, the complex conditions under which things can make a definite difference to each other, and under which propositions can be meaningfully true or false.

I'm not arguing against the use of logic, of course. I'm arguing that there are other aspects of physical existence that need to be considered. To reduce physics to logic is much the same as reducing human language to logic, assuming all the conditions of meaningful communication are irrelevant.

Logic and mathematics are abstractions supported by the complex functionality of language. I think the logical and mathematical aspects of physics are likewise abstractions from "physical existence" -- a complex functionality that we generally take for granted.

friend

Sep19-09, 10:01 AM

Let me ask some questions to get a better understanding of your second statement:

Do you believe that natural numbers exist?

Do you believe that this is not only a platonic existence, but that there is a level of mathematics (say the natural numbers) that IS physically EXISTING = fundamental physical entities (which we haven't discovered so far).

Do you believe that you can somehow construct physical laws (which rely on more than logic) from logic itself? That means do you think that natural numbers, real numbers etc. emergy somehow from logic alone?

Or do you think that if we uncover the ultimate laws of science those concepts fade away as purely approximate descriptions and we are faced with a system of logical automata interacting with each other?

No, at this time I don't believe numbers in and of themselves have any physical meaning. Propositional logic and numbers and math are only a human contrivance of language to help us better describe reality. There are no fundamental particles that have a "1" or a "2" written on them. We can just as easily count them in a different order.

I don't know how numbers can be derived from logic alone. I understand Whitehead and Russel wrote a book doing just that. They also attempted to proved the completeness of math, but failed.

However, I do believe that the laws of physics can be derived from principle alone, without the need for measurement. Although, we might need measurements in order to check the math. For example, I've seen derivations of the path integral from logic alone. It's not on the arXiv yet, so I'm not allowed to publish here. PM me if you are interested in seeing it.

friend

Sep19-09, 10:15 AM

Friend -- The point I was trying to make above (#149, 186) is that this binary representation of physical existence isn’t adequate. For a proposition “A exists” to have any meaning, it must be possible for something to determine something about A through interaction, within some particular frame of reference.

Yes, binary logic may not be sufficient, we do end up using numbers to quantify things.

But when you say, "it must be possible for something to determine something about A through interaction", I'm understanding material implication from that; we need some sort of B to prove A. Yet this is part of binary logic as well.

Fra

Sep19-09, 04:01 PM

I think we're starting to reach a mutual understanding of positions.
OK, now you position is clear. You include in the process not only nature's evolution of laws but also our quest for these laws. My feeling as that it becomes al little too subjective, but that's my position - and I don't want to repeat it here.

Yes. I also understand why you think my position is a subjective - it is. The question where we differ, if it's avoidable or not - does the real world fit into a static description?

Yes, you are right. As I just said I can only tell you how it does NOT work (what a pitty). If it is this what you mean by "halting" then I agree.

Yes something like that is what I mean.

You have chosen to search for evolving laws - and you somehow adapt your search strategy accordingly. You are like Achilles running after the turtle. You never overtake the turtle, but you are coming closer and closer - and perhaps this is the best you can do.

That analogy seems a bit odd :) but it's true that I think the point is the quest for best performance. The perfect performance might be impossible.

Implicit in my reasoning is indeed a special view also of the philosophy of science. I use the very same abstraction to describe the scientific method & process, as I use to describe physical law and physical processes.

If we focus on the nature and existence (or emerence) of laws then we disagree - but that's the interesting point here :-)

Yes, I think this is where from my point of view, I would classify you as a kind of structural realist, enough though you currently seems to be in a process of finding out the problems of this approach and it seems, like you say yourself that you've at least partially found out what does not make sense.

I'm curious to see what your understanding eventually evolve into :)

/Fredrik

moniker2

Sep19-09, 07:53 PM

does the real world fit into a static description? I think so....if you look at the world in terms of frames of time.

friends, I would like to bring up a theory I read two years ago. It's starts with the idea that LHC will not find any Higgs Boson particle, and it looks at the idea of quantum inertia. I think it's seven equations in total, but i'm not sure.

tom.stoer

Sep20-09, 03:26 AM

I don't know how numbers can be derived from logic alone. I understand Whitehead and Russel wrote a book doing just that. They also attempted to proved the completeness of math, but failed.
I think set theory was required as well.

tom.stoer

Sep20-09, 03:57 AM

I am still thinking about axiomatic systems plus a selection principle.

Let's make an example (we already discussed the exotic differential structures briefly; I think they can serve as a good starting point).

Assume that for some reason nature decided that its existence is based on manifolds. Now let's count manifolds (up to their symmetries). I guess we agree that we can count manifolds with respect to their dimension. Then I guess that for each dimension n we can count manifolds with respect to topological / geometrical building blocks (this is known in n=2, was conjectured by Thurston for n=3 and proven by Perelman: http://en.wikipedia.org/wiki/Geometrization_conjecture). In all dimension but 4 and we can count manifolds with respect to their differential structures. In n=4 the standard R^4 escapes counting as its family of non-diffeomorphic manifolds is uncountable (http://en.wikipedia.org/wiki/Exotic_R4).

At the same time most (all?) physical laws are local (differential equations), and locally all exotic R^4 spaces are diffeomorphic = physically indistinguishable.

Assume now that all those different manifolds exist in the sense as dicussed above: A mathematical structure is a universe. Therefore we have a countable set of manifolds w/o differential structure. Then we have a countable set of manifolds with different differential structures based on topologies different from R^4. And then we have an uncountable set of R^4 with different differential structures.

Now picking one manifold randomly will - with probability one - select an R^4 manifold. But as I said, locally all R^4 manifolds will be identical. Therefore we found a selection principle telling us that we are living in R^4.

I know this is not a perfect example, but it shows how a selection principle could emerge from deeper principles w/o using it as input. This is still my belief: Physical existence is based on mathematical principles. These principles allow us not only to describe what exists but to some extend to explain why it exists and why it is the way it is. Of course we have to use some axiomatic input (in my example it's the idea that nature is based on manifolds and that every manifold exists both in a platonic way and physically).

Remark: no version of the antropic principle was required! Math alone was sufficient to explain why we live in an n=4 differentiable manifold.

Fra

Sep20-09, 05:58 AM

I can symphatize with the desires to find constrainst to select away options. Given a choice of inference system, I think that one can certainly make an inference of some type.

Here is one way to connect my thinkg to Tom's thinking:

Assume nature is like THIS, then we might be able to find some constraints (deductive or inductive depending on the type of inference system) acting as a kind of "selection".

What disturbs me in general, is that the choice of inference system (axioms in your case) is ambigous. However I'm the first to acknowledge that this is unavoidable, since you need a current position, in order to make relative progress. The inference system is part of the position to me.

In a certain sense, I think any starting point must be valid as long as it, itself, is subject to selection and critics.

What I mean is that, consider 3 groups of scientists/observers...

One starts with an null hypothesis that the earth is a flat pancake.
One starts with the null hypothesis that the earth is a torus.
One starts with the null hypothesis that the earth is more or less a sphere.

Once they put the hypothesis to test, two of the groups will be forced to revise their hypothesis, and in the end they will be in agreement.

Here the initial hypothesis isn't important, it's the scientific process itself that does the trick.

However, there is one important thing here which is that the initial inference system and hypothesis, must be able to be encodable with respect to the observers. In particular do I see it in a way that if you think of the inference system (the conjectured/hypotized law) as a computation, then computer is the observer. Clearly the complexity of the computer limits how complex algorithms you can compute.

Alot of the time when human scientists imagine, the inference machinery that are to apply to physical systems, the human limit is almost unlimited as what one can compare to say an electron. We can certainly ask questions that an electron can't.

So I try to ask myself like, what questions would I ask, if I were an electron? :) Quickly one can first post another question, what questions COULD I even FORMULATE if I were an electron?

Then I ask, what happens if I ask, what questions COULD a system x formulate, and then ponder what the limit complexity(x) -> 0 looks like. For sure then the options should be fed enough to possibly be finite.

There I have my starting point. This is principally as ambigous as tom's choice of more complex axioms, but I defend it with thta it's from my point of view, the smallest possible speculation that I have to do, to be able to make any predictions whatsoever.

Then I ask, what happes to this proto-inference system, as again complexity(x) -> grows.

/Fredrik

tom.stoer

Sep20-09, 07:48 AM

Frederik,

don't focus so much on my (preliminary) axioms. I simply wanted to provide an example where one can see a physically viable selection principle emerging w/o the need to be put in by hand.

ConradDJ

Sep20-09, 08:16 AM

Assume that for some reason nature decided that its existence is based on manifolds...

This is still my belief: Physical existence is based on mathematical principles. These principles allow us not only to describe what exists but to some extend to explain why it exists and why it is the way it is.

I understand why mathematical principles can seem more fundamental than physical ones – why again and again the quest is renewed to find a reason for the known physical principles in principles of math or logic. But in the first place, we’re always using physics as a guide to choosing a mathematical starting-point... which is otherwise arbitrary, from a purely mathematical point of view. Why manifolds?

And in the second place, what kind of success can we expect from this quest, and what would be accomplished if it succeeded? Suppose the original hope of string theory had proved correct, that there was only one mathematically consistent theory that was also consistent with all the complex symmetries in particle physics, including gravity? Or suppose it turned out there was only one mathematically viable formulation of quantum gravity. Something like that would at least give us a reliable starting-point for trying to understand why the world is built the way it is – but it would hardly be an answer in itself.

So I think it’s worthwhile to ask how we might expect to answer the fundamental questions, based on what we know about physics. One of the things we know is that the universe has changed very radically over 13+ billion years, and all or nearly all the physical structure of our world did not exist at the beginning. This in itself seems to point to something very different from mathematical principles, as a starting-point, and raises the possibility of an evolutionary explanation. We know from biology how powerful that can be, as a way of explaining why things are the way they are.

Another thing we know is that what things are and how things happen, in physics, has to do in some way with the complex processes by which information about things is obtained and communicated. Whatever happens in the “collapse of the wave-function” seems to be basic to the emergence of definite information in the physical world, but it’s not clear what if anything it has anything to do with mathematical principles, since it happens at random.

Fredrik’s project seems odd to me in some ways, but I’m rooting for him because he’s doing something that seems to me important – trying to develop an evolutionary approach that takes into account the information-capacity of physical systems. Mathematics plays a key role, but there are good reasons to think that what’s going on in the physical world – even at the foundations – involves more than mathematical consistency.

ConradDJ

Sep20-09, 08:44 AM

In a certain sense, I think any starting point must be valid as long as it, itself, is subject to selection and critics...

However, there is one important thing here which is that the initial inference system and hypothesis, must be able to be encodable with respect to the observers...

So I try to ask myself like, what questions would I ask, if I were an electron? :) Quickly one can first post another question, what questions COULD I even FORMULATE if I were an electron?

Hi Fredrik –

Specifically, what seems odd to me in the way you explain your approach is that it focuses on the complexity of information a physical system (“observer”) can contain (“encode”) and process in some way (“inference”).

This makes sense to me as one part of the issue – but what doesn’t come into focus for me is the interaction-context... which not only communicates information to the observing system, but would also (I assume) be what poses the question the observer is trying to “infer” an answer to... and would also be the context for the observer’s “action” that results from the inference, which would presumably alter the environment for other observers.

I see the point of taking an “internal” view of the world... but it’s still a view of the world “out there” in which each system participates with others. So I’m trying to see what this informational interaction-context looks like. What would the electron’s “inference” be? What would the input be, and what would be its “action”?

I think what you’re saying is, that the basis for a TOE should be not just mathematical consistency per se, but what can appear consistently to a physical system in a particular context... which might then be the basis for a further (random?) search for possible consistencies. So mathematical consistency would be one aspect, and which sorts of mathematical consistency are physically relevant could change as the systems evolve.

tom.stoer

Sep20-09, 02:21 PM

I understand why mathematical principles can seem more fundamental than physical ones ... Why manifolds?
It's hard to distinguish between mathematical and physical principles. I tried to explain my position a couple of days ago: usually you start with a physical principle and develop a theory out of it = develop a math framework. During the development the physical principle may be transformed into a mathematical one. Look for example at the principles in special and general relativity.
Why manifolds? I don't know. It is just a starting point for my example. The fundamental principle "manifolds ..." is not so interesting here. My idea was to demonstrate how from such a principle selection criteria may arise.

Or suppose it turned out there was only one mathematically viable formulation of quantum gravity. Something like that would at least give us a reliable starting-point for trying to understand why the world is built the way it is – but it would hardly be an answer in itself.
You are right; it wouldn't explain "why QG at all - and not game of life". So you would have to step back and think about your unique theory again. Hopefully you will find a hidden and more fundamental (physical) principle from which this uniqueness follows. At some point it may be appropriate to think about an evolution process, but as I said: I do not (yet) see a good starting point for an evolution process - and I still like the axiomatic approach more ;-)

... that the universe has changed very radically over 13+ billion years, and all or nearly all the physical structure of our world did not exist at the beginning. This in itself seems to point to something very different from mathematical principles, as a starting-point, and raises the possibility of an evolutionary explanation.
Not really. The standard model plus GR seem to explain the different structures on different scales (different ages) quite well. It's the same with evolution in biology: The fundamental laws (selection due to environmental pressure, survival of the fittest) and the building blocks (DNA, RNA) are static but nevertheless allow for a dynamic evolution process. That's for me a very good reason not to let everything become dynamic, emerging, relative and - hopefully not - arbitrary.

Whatever happens in the “collapse of the wave-function” seems to be basic to the emergence of definite information in the physical world, but it’s not clear what if anything it has anything to do with mathematical principles, since it happens at random.
I agree that the ontological interpretation of qm is by no means clear; but to take the wave function as a physically real entity is - if you ask me - not a very good choice.

... what’s going on in the physical world – even at the foundations – involves more than mathematical consistency.
Yes, but not less, either!
The biggest successes in physics were always backed up by mathematical consistency (Newton invented both his dynamics and analysis; Maxwell's theory = collection of known physical phenomena + partial differential equations; quantum mechanics = collection of known physical phenomena + Hilbert spaces etc.).
The current situation in physics is vexing: we are losing plausible physical input due to the fact that the domain of quantum gravity is hardly accessable by experiments. At the same time mathematical rigour fades away! As far as I know NO quantum field theory except the non-interacting ones are proven to exist mathematically. A couple of days ago I found a paperon arxiv (I have to post a link here) how rather clever people tried to construct 3- and 4-loop measure and amplitudes in string theory - a theory claiming since a quarter of a century that the perturbation series is well-defined and that no divergencies exist has not even started to define the n-loop amplitues for all finite n!

Why all this? Because I think that for a generation heading for a ToE I expect some carefulness before starting with multiverses etc. I have the feeling that we can learn much more from current physics if we study its phenomena carefully, take all facts into account and develop a sound mathematical system. After we succeed with this task it's time for the next meta-level.

Fra

Sep20-09, 04:24 PM

Hello Conrad,
I see the point of taking an “internal” view of the world... but it’s still a view of the world “out there” in which each system participates with others.

We should distinguish between the view OF the outside (from the inside), and the view FROM the outside, I'm not sure what you mean here?

If we are talking about the view of the outside (from the inside), then that is still constrained to the complexity of the observer; since all we have is an IMAGE of the outside, but "painted" on the inside screen (very loosely put but I think you get the point). This IS the context of the inside view. From the inside point of view, the environment is like a "black box", whose actions and structure the observer is trying to predict.

I make this distinciton.

The the actions are independent on the external unknown black box. The actions depend only on evidence existing on the inside. The REaction from the environment OTOH is in principle unpredictable, and this is what generally makes the inference system on the inside revise. The inference system doesn't contain information to predict it's own evolution. Each inference system has a kind of "self-evolution" which is what to expect if no feedback is given from the environment.

This latter is a kind of correspondence to "measurement", and the self-evolution is the regular equations we would write down. IE. the schrödinger eq applies only in between measurements. If the schrödinger contained the information to predict the deformation needed at each measurement then it would contradict itself.

If we are talking about the outside view, then you have introduced another observer, and generally two observers are interacting.

In a certain sense it's obvious that to an inside observer, the environment is a black box, and if you think of the black box as the "context" to give feedback as to evolve the inference system then that's not know from the inside. The only way to get to know it, is to play the game, take an action and await the reaction, and revide your inference system accordingly.

If the inside observer could predict this entire evolution of himself then the entire discussion wouldn't be nessary. The fundamental problem, that I acknowledge is that generally we are forced to take actions based upon incomplete information. And of course the reaction is not deterministically predictable.

So I’m trying to see what this informational interaction-context looks like. What would the electron’s “inference” be? What would the input be, and what would be its “action”?

Of course, my approach isn't developed enough to answer this yet.

If I were to elaborate this it would probably take us even further away.

The "microstructure system" of the electron would have a representation here.
This representation implies an inference system. Each inference system contains a "natural action", which would encode the say "naked interaction properties" of the electron - what the interaction properties of the electron SEEMS to be, from an outside observer is still more complex. A kind of renormalisation would be built into this.

Hopefully the inference system, would explain why an electron say only responds to gravity and to EM fields: the idea is that this analysis should reveal WHY the other interactions are indistinguishble to the electron, and therefore it's action is invariant with respect ot them.

(Or of course, if this is just an approxiation, then any corrections to the action should come here)

So, I'm still trying to develop this idea. For example, in my approach, I have not yet even reconstructed something like the 4D spacetime, neither have I reconstructed any microstructure of matter, so I couldn't possibly have any postdictions of the properties of the electron yet.

I do start with some subjective assumptions that are the least speculative I can come up with, but these concern the revision of the inference systems; which is the direct physical analog of the scientific method; howto revise a hypothesis in the light of contradicting evidence. Not the exact makeup of them as such; that should follow from the design principle given a seed that could be chosen at random or at will.

/Fredrik

moniker2

Sep21-09, 06:39 AM

The theory is reformulation of Albert Einstein 1905 work. It takes the mutual opposition of Lenard, 1910, and is written in terms of Isaac Newton’s idea of absolute space and time. It stipulates that space-time vacuum share similar properties to a non-Newtonian fluid causing particle polarities.

Fra

Sep21-09, 01:01 PM

It's the same with evolution in biology: The fundamental laws (selection due to environmental pressure, survival of the fittest) and the building blocks (DNA, RNA) are static but nevertheless allow for a dynamic evolution process. That's for me a very good reason not to let everything become dynamic, emerging, relative and - hopefully not - arbitrary.

I have to object here. To call the DNA/RNA and the the relevant replication and synthesis machinery in a cell a "static" doesn't seem to nearly appreciate the depth of life. There was certainly a time where there was no earth, no DNA molecules, not even proteins, and not even atoms.

So I think it's clear that the static abstraction there fails.

/Fredrik

tom.stoer

Sep21-09, 01:18 PM

I have to object here. To call the DNA/RNA and the the relevant replication and synthesis machinery in a cell a "static" doesn't seem to nearly appreciate the depth of life. There was certainly a time where there was no earth, no DNA molecules, not even proteins, and not even atoms.

So I think it's clear that the static abstraction there fails.

No, it doesn't fail. I agree that the structure of laws of physics and biology do match completely; but that's not the point here. My conclusion is that it is not sure that dynamic processes require dynamic laws. Far from it, progress in science tells us that in many cases the underlying laws of dynamic processes are static laws.

Fra

Sep21-09, 04:18 PM

We seem to interpret current knowledge in different ways. You seem to think it supports your point, I think the other way :) Anyway, I understand your reasoning.

My conclusion is that it is not sure that dynamic processes require dynamic laws.

I agree, it's not certain, but neither is the opposite. My view doesn't say all laws HAVE TO change, it just says it's not certain, and just that the static cases are either special cases.

Far from it, progress in science tells us that in many cases the underlying laws of dynamic processes are static laws.

The question is what is cause and effect here? For sure, stable laws are preferred by the scientific method, for obvious reasons. So, are we discovering the static laws, or is the very interactions that creates/selects them?

If we look at the history of science the picture is dual. Yes, all laws of physics have usually been static, and timeless BUT these "timeless" laws nevertheless keep chaning the more we learn. The usual idea is simply that we had the "wrong" timeless laws, but that is exactly my point. Even a "timeless" law, that is not inferred to absolute certainty, are always subject ot possible negotiation in the future - so it's not really timeless after all.

/Fredrik

tom.stoer

Sep21-09, 05:19 PM

What shall I say? As already explained your point of view seems to be "too subjective" - but you are right, both positions are allowed logically.

I do not say you are wrong, I just have the feeling that it's perhaps too early to start this kind of reasoning. My example with string theory goes exactly in this direction: there is still much we can learn from "ordinary" physics and sound mathematical frameworks. But of course that's not a dogma, it's only my private view.

Last but not least I don't want to insist on my view as it is not as elaborated as yours.

Tom

Fra

Sep21-09, 05:48 PM

I do not say you are wrong
I might certainly be wrong of course, I like to think I'm sane enough to see the limits of my own inferences as well. If I thought I couldn't be wrong, I wouldn't even be selfconsistent :rolleyes: Instead of beeing certain, I have a more modest requirement: I just need to be confident enough, to be able to place my bets and beware of the risks.

But it's interesting to see other peoples position and try to understand the logic of inference system. That's how I see this. Your inferences seems "rational" within your inference systemm, and your reasoning points out a little from others since you do somehow want to stick to the axiomatic systems, but at the same time you seem to acknowledge some issues with it. Alot of other people that do the static inferences, doesn't seem to reflect upon this as seriously as you did. I guess that's why your somewhat "structural realist" reasoning was different that those that doesn't seem to sniff the problems.

I'll probably be a little less active for a few days since I've got some more travelling coming up.

It was nice to argue with you.

/Fredrik

tom.stoer

Sep24-09, 01:13 AM

But it's interesting to see other peoples position and try to understand the logic of inference system. That's how I see this. Your inferences seems "rational" within your inference systemm, and your reasoning points out a little from others since you do somehow want to stick to the axiomatic systems, but at the same time you seem to acknowledge some issues with it. Alot of other people that do the static inferences, doesn't seem to reflect upon this as seriously as you did. I guess that's why your somewhat "structural realist" reasoning was different that those that doesn't seem to sniff the problems.

I'll probably be a little less active for a few days since I've got some more travelling coming up.

It was nice to argue with you.

I would like to return that compliment. It was a very good discussion!

As I said: I am not so sure about my own position; it's still a moving target and therefore I appreciate conflicting but well-grounded ideas. The main problem is - as I already said - and this applies to my own ideas as well - that after starting to think into one direction, I always find very good reasons why it will NOT work that way or why I DON'T like it that way ...

Fra

Sep24-09, 10:02 AM

The main problem is - as I already said - and this applies to my own ideas as well - that after starting to think into one direction, I always find very good reasons why it will NOT work that way or why I DON'T like it that way ...

I know the feeling.

I still remember my first reaction when I learned about QM. Before I seriously studied QM, I was pretty much a realist, and I still remember a moment during a class at my first QM course when I realised that the realist interpretation does not make sense and suddenly a light came on for me and my first reaction was that "all these years I have been scammed" and kept away from the light :biggrin:

/Fredrik

tom.stoer

Sep24-09, 05:42 PM

For me it was different.

When I tried to understand QM and QFT I decided to become a positivist - just to make some progress and manage the maths. But over the weekend I was a realist and believed in a real world "existing out there".

Fra

Sep25-09, 12:35 PM

It's certainly hard to be overly critical when you are supposed to study something from the practical point of view of study techniques. During the courses my approach was a mix of shut up and calculate and axiomatic view. To defend the choice of axiomatics temporarily the experimental success of the predictive machinery was my defense to reduce the frustration.

But from a more serious perspective (set aside the practical problem of managing and completing courses) this is just a pragmatic way of handling daily business.

But after that moment I was never realist, not even on weekends :)

/Fredrik

Chronos

Sep26-09, 08:24 AM

Well, if the laws of nature are dynamic, the task of modeling reality is compounded. No model will ever be accurate because component information was derived at different points in time. Chicken soup consists of squawks past plus grain cubed, as my inscrutable grandmother was fond of saying.

Dmitry67

Sep26-09, 04:16 PM

Sorry, I had missed a lot...

Just 2 cents about the binary existence.
I would say, there are 3 levels of existence:

Something exists and we can provide an example of such object;
Something does not exist and we can prove it

and between them:

Something exists in a sense that we can prove that statement

\vdash \exists Y : BlahBlahBlah(Y)

But no example of Y can be provided. Good example is Banach-Tarsky paradox, I wrote about it here: http://www.physicsforums.com/showthread.php?t=337197

Dmitry67

Sep26-09, 04:19 PM

I agree to one part of the statement: 1) Everything that EXISTS must respect some laws of (binary???) logic and therefore correpsonds to some consistent mathematical system. But the other way round it's deep philosopophical statemet which I cannot accept w/o further discussion: 2) EVERY sound mathematical (logical) system EXISTS.

Ha! looks like I did not miss anything, because we were discussing exactly that - remember, I was talking about the informational interpretation of Ocamms razor?

tom.stoer

Sep27-09, 03:29 AM

... looks like I did not miss anything, because we were discussing exactly that

You missed a lot regarding the emergence of physical laws from inference and "evolution" - but that's not really my position :-)

Regarding you levels of existence: sometimes I have the problem that currently all latex formulas are displayed as black boxes, so I can't read it (sometimes they are displayed properly). Do you know the reason?

You intermediate level is due to the non-constructiveness of proof of the existence. All proofs relying on the axiom of choice suffer from that issue.

Fra

Sep27-09, 03:59 AM

Regarding you levels of existence: sometimes I have the problem that currently all latex formulas are displayed as black boxes, so I can't read it (sometimes they are displayed properly). Do you know the reason?

I have noticed the same problem.

In old threads, the latex pictures look fine (with my same browser). But since some time ago the new posts with latex are black and unredable. The picture is fine if I save it locally and view it in some image program. Then problema appears to be that my old browser (IE6; I have reasons for not having upgraded so far) for some strange reason fails to display this version of the png file.

I tried firefox and it works perfect. And older Opera also works fine. So it seems IE6 is the only one I've tried failing to display the pictures. About the newer IE I don't know.

/Fredrik

Dmitry67

Sep27-09, 04:38 AM

I see formulas without any problems (IE8)

Well, may be I missed the "evolution" stuff, bu I really dont understand it.

How physical laws may change? If something changes over time (like Hubble 'constant') then it is just a part of more fundamental and constant law

I can believe that parameters of the Standard Model can be different in different 'bubbles' - but in that case there is common superstring background, with more fundamental laws, describing how universes with different parameters are created (branes colliding in high dimensional bulk space, different angles of collision create bubbles with different parameters, blah blah, something like that)

But in any case there MUST be fundamental TOE which is eternal and purely mathematical.

Fra

Sep27-09, 05:02 AM

Well, may be I missed the "evolution" stuff, bu I really dont understand it.
...
How physical laws may change? If something changes over time (like Hubble 'constant') then it is just a part of more fundamental and constant law
...
But in any case there MUST be fundamental TOE which is eternal and purely mathematical.

I think we had some discussions on this before, and the conclusion as far as I remember is that you are far more of a realist, and I am much more subjective relative to your position.

We might not want to repeat everything, but I think have at least from my point of view addressed the questions you raise here - which are very typical realist objections to the notion of evolving law.

The core difference is that I am looking for an intrinsic measurement and inference theory. In that sense, it's not possible to arrive at an inference like you do: "there MUST be a fundamental TOE which is eternal". To me, such statement is more an expectation and vision, not a certain deductive inference, because I doubt you can prove it? :) The expectation and vision is rational, but expectations and visions change. The rationale for the acting as they are eternal, is because from the inside point of view their uncertainty is not distinguishable. This type of reasoning can not be understood in standard QM, it suggest a reconstruction of measurement theory, where QM is a special case.

But I think I've tried to argue several times but apparently the reasoning comes out as implausible to most.

/Fredrik

BigFairy

Sep27-09, 05:38 AM

yeah you can kinda agree..

friend

Sep27-09, 10:48 AM

The core difference is that I am looking for an intrinsic measurement and inference theory. In that sense, it's not possible to arrive at an inference like you do: "there MUST be a fundamental TOE which is eternal". To me, such statement is more an expectation and vision, not a certain deductive inference, because I doubt you can prove it? :) The expectation and vision is rational, but expectations and visions change. The rationale for the acting as they are eternal, is because from the inside point of view their uncertainty is not distinguishable. This type of reasoning can not be understood in standard QM, it suggest a reconstruction of measurement theory, where QM is a special case.

But I think I've tried to argue several times but apparently the reasoning comes out as implausible to most.

/Fredrik

I don't see how anyone can put any faith in evolving laws of physics, because then they would change in a way we can't predict, unless of course there is some more fundamental laws that govern how things change. So either you have faith that there must be some sort of constant fundamental law, or you have no faith at all, and you're just curve fitting the data from experiment.

atyy

Sep27-09, 11:01 AM

I don't see how anyone can put any faith in evolving laws of physics, because then they would change in a way we can't predict, unless of course there is some more fundamental laws that govern how things change. So either you have faith that there must be some sort of constant fundamental law, or you have no faith at all, and you're just curve fitting the data from experiment.

Does every solution have a question (come from a set of equations)?

tom.stoer

Sep27-09, 11:09 AM

... unless of course there is some more fundamental laws that govern how things change.
That's exactly my position when I compare Fra' ideas with biological evolution. Biological evolution is based on fundamental laws (DNA) which are not subject to the evolution process itself but provide a fixed, external system.

If physics behaves in a similar way than our job is to deduce these fundamental laws.

friend

Sep27-09, 11:46 AM

Does every solution have a question (come from a set of equations)?

My belief is that there will always be questions and we will always be seeking equations until everything can be derived from logic itself. Are we really going to be satisfied with reducing things to some sort of particle and some sort of force? We might get smaller and smaller particles, and we might find symmetries in the equations. But that still leaves us asking why, why, why. But if things are reduces to logic itself, then the only thing left is to question reason itself. And the answer to why logic is the way it is is because either things exist or they do not, statements are either true or they are false.

Fra

Sep27-09, 12:27 PM

Friend and Tom, your objection is clean and understandable! It's I would say the most expected objection to evolving law.

But there are subtle things that are the beauty in the approach that I have tried to elaborate on in several ways in several threads. I guess you require some concrete demonstration of the success of the principle to be see the point. Then I think more work is needed. I have revealed some of the conceptual and principles behind the reasoning, but the result of this in terms of a solving open problems in physics is of course still very much in progress.

I don't see how anyone can put any faith in evolving laws of physics, because then they would change in a way we can't predict, unless of course there is some more fundamental laws that govern how things change. So either you have faith that there must be some sort of constant fundamental law, or you have no faith at all, and you're just curve fitting the data from experiment.

Your latter choice is closer to my view, but you simplified it grossly when you mention curve fitting. But in a sense, a rational guess, is like a kind of rational inference in the sense of an probable extrapolation of the future, based on the past.

You can if you like call this a curve fitting extrapolation of the past, to the future. But the obvious problem is that the curve fitting is not unique. You end up with a landscape of possible extrapolations? In my view, there is a information divergence measure which guides the choices of "extrapolation parameters". It's in this space there is evolution as diversity and seleciton. The diversity is already there due to the uncertainty, but the important thing is that the diversity is constrained.

But a real inference machinery does not have all the history of the universe - it has only a reduced and compressed history to base the inference on; this inference leads to a rational action.

In this scheme, it's correct that there are things that are undecidable and unpredictable. But this does not preven us from making a kind of probable inference, or induction.

The real benefit of this approach is that one can make predictions, not as deductive inferences, but as uncertain inductive inferenes as to what the future will be, and this expectations yields a rational action of the inference system (matter system). IE. the mere conjecture that physical actions ARE involving a kind of uncertain inference, and that the inference machinery is bounded by a complexity, gives constraints on the effective fundamental action one would expect in nature.

IE. the uncertainty of the state of matters that insist on, does suggest a kind of associated action, that is construced from natural inference. This is why states, and states of laws (as implicit in physical actions) become comparable and it's not consistent to think of state of laws and configuration states as fundementally different if you take the measurement perspective; because then parts of the the laws are dismissed to background information, or background context.

I am not saything there is no context, I'm saying there is a context, but it's evolving. And at some point, there is a context whose evolution simply isn't predictable. To say that it could be predictable, but the predictions isn't made yet, just favours my point.

This is much deeper than just curve fitting. It also contains an reconstruction of information theory, that does not start with standard probability and continuums. But I obviously fail to convey what I mean. So we'll let this be some crazy mens opinon until some time later when maybe I get to make some progress, or someone else who is working in related directions are able to make some progress.

But any progress would be made against the collective opinion, rather than in line with. This is why the activation energy for this approach is extra high. Apparently it's hard to convey the reasoning, so that leaves only the hard concrete progress.

/Fredrik

Fra

Sep27-09, 12:43 PM

And the answer to why logic is the way it is is because either things exist or they do not, statements are either true or they are false.

What is the meaning of beeing true, if it can not be proved from where you stand? the freedom to add another axiom saying it is? or what? Then ponder that the set of axiom is bounded in complexity; what do you do? You might need to erease one previous axiom to add a new one?

I see that you seem locked into this rigid realist type of logic, and I totally do understand that from your perspective evolving law simply makes no sense.

I think the type of motivation I would have to provide to prematurely motivate the reasoning behind evolving laws and physical action based on inductive inference, is that your way of reasoning risks getting stalled or run into a halt. It's not flexible enough. I think Tom was sniffing in this direction, but he still has not come over to the dark side, but I think in time he will :wink:

/Fredrik

marcus

Sep27-09, 12:45 PM

... unless of course there is some more fundamental laws that govern how things [i.e. laws] change...

That's exactly my position when I compare Fra' ideas with biological evolution. Biological evolution is based on fundamental laws (DNA) which are not subject to the evolution process itself but provide a fixed, external system.

If physics behaves in a similar way than our job is to deduce these fundamental laws.

This sounds like a clear statement which agrees with our experience of the history of science.
Humans have repeatedly deduced patterns of regularity and formulated laws, and repeatedly they have then learned that these laws vary according to deeper laws. Can't we learn from that? Isn't it reasonable to expect this process to continue?

An example that comes to mind is Euclidean geometry. For many centuries it was a law of nature that the angles added up to 180 degrees and light traveled on straight lines, and everybody knew this. Galileo founded modern science based on such laws, and for centuries nobody questioned Galilean relativity either.

Then we found out what causes spatial geometry to be approximately Euclidean. Euclid is a temporary solution to a general equation governing the evolution of geometry. We now know why Euclid and we know not to assume that Euclid works in all times and places. There is a deeper law of geometry that explains the previous shallow law. We found that the geometry of the universe is evolving with time. And also our local geometry is evolving. According to a deeper law. Or if you don't like the word "law" then according to a deeper regularity or rule. It is our experience that law evolves with time.

Laws are just patterns of regularity that we notice and continually test, and they change. And happily enough (or because we've gotten good at the job), the human-noticed rules change only very slightly and slowly, so that we can get a lot of use out of them. We can treat them as reliable within some domain of applicability. Part of knowing the law is knowing the domain.
=====================
EDIT TO REPLY TO NEXT
Friend, "bottom up" and "top down" are idealizations, artificial constructs. It is not either/or. We humans arrive at laws however we do it, in whatever ways we always have done it. A method has never been accurately formulated, or universally adhered to, and even if one had been deduced from past practice it would not necessarily apply in the future. We do not entirely know how we have, and will, perceive test and formulate laws.
We only know that biological evolution has prepared us to figure out patterns and we are reasonably good animals at doing it, and it works seemingly pretty well.

You mentioned "faith" in your earlier post. I do not see how "faith" is involved. Beyond that of gradually learning from experience and doing what works.

In this next post you mentioned "debate" between different idealizations about how we do physics. I don't see the point of debate. There is a community with some written and unwritten traditions, an ethos, a social structure, it operates as it operates. At various junctions there is struggle. We do not know how it will operate in the future and our ability to affect how it will operate is limited.

friend

Sep27-09, 01:16 PM

This sounds like a clear statement which agrees with our experience of the history of science. Humans have repeatedly deduced patterns of regularity and formulated laws, and repeatedly they have then learned that these laws vary according to deeper laws. Can't we learn from that? Isn't it reasonable to expect this process to continue?

I guess this brings up the debate between the bottom up or top down approach to discovering physical laws. Do we find the most fundamental of principles by interpreting equations that fit ever more accurate measurements? Or can physical laws be derived from principle alone? The former question leads us to ask if we can even possibly measure with enough accuracy. And I suppose this latter question brings up what fundamental principles do we start with and how much can we trust them.

It seems for certain we will not get there through measurement since we will never be able to achieve the energies high enough to test curve fitting theories. We'd have to recreate the big bang hundered of times over to see if we get the same laws of physics within a given probablity. But do we have any principles alone from which physics can be derived? I think we do. Whatever the question or theory proposed, we always end up asking whether it is true or false. So surely binary logic has to be at least part of the starting point. Surely, if we are trying to "prove" something, logic is involved. The question is how to proceed from logic to physics. How does math enter the effort? And how would we confirm that it is correct? Would it be sufficient if such an effort reproduced the mathematical structures of QM and GR? Or would we have to reproduce the SM?

marcus

Sep27-09, 02:03 PM

...It seems for certain we will not get there through measurement since we will never be able to achieve the energies high enough to test curve fitting theories...

Aren't you making an artificial and useless distinction between "measurement" methods and the opposite (non-measurement?) methods?

Aren't you again making an artificial distinction between "curve fitting" theories, and some other (well defined?) type of theory?

How can you pretend to know in advance what patterns of regularity humans will or will not be able to test?

Surely not every approach to testing involves artificially generating high energies! :biggrin:
That is merely an illusion created by our recent experience with accelerators and colliders.
You look at 50 or 60 years of history and think that there is an iron law and it will always be this way.
People are already fitting their curves to the night sky, and they have only begun to watch the sky really intently.
Please cut your fellow animals some slack before you start making philosophical pronouncements about what we cannot do. We are just getting started.

Dmitry67

Sep27-09, 02:42 PM

Fra, lets not repeat all arguments again. But Max Tegmarks hypotesis has several concrete and falsifiable predictions. Could you list any predictions of the theory you prefer? I have an impression (may be I am wrong) that if that evolving law thing is true, on our way to the ultimate TOE we will get dissapointed by our inability to build a formal system which describes the Universe. Trying to find the TOE we would understand that no TOE is possible. End of physics...

friend

Sep27-09, 02:58 PM

Aren't you making an artificial and useless distinction between "measurement" methods and the opposite (non-measurement?) methods?

Aren't you again making an artificial distinction between "curve fitting" theories, and some other (well defined?) type of theory?

How can you pretend to know in advance what patterns of regularity humans will or will not be able to test?

...
Please cut your fellow animals some slack before you start making philosophical pronouncements about what we cannot do. We are just getting started.

Perhaps I've not considered well enough, but it seems to me that any measurement based curve fitting approach is inherently incapable of discovering the completion of physics. How are we supposed to know when there's nothing more to discover? When do we know that it's impossible to break up particles into smaller constituents? And how do we know the same laws of physic applies everywhere? We can't measure everything, so we can only guess that it's universal.

Dmitry67

Sep27-09, 02:59 PM

Tom, I have a tricky question regarding the Occams razor thing we discussed before (everybody is welcome)

So, it is very likely that our universe is infinite. As we know, the expansion is accelerating, so there are cosmological horizons: we will never ever be in causal contact with some distant areas of our universe.

My question is: do these areas really exist?

I can open my cards, explaining why the question is tricky. Compare:

A1. Yes, of course, these areas exist! Why not? Yes, we will never be in causal contact, so what? Our mathematics and cosmological models tell us that these areas do exist!
A2. No. We will never be able to observer these areas. hence, they are just mathematical way to explain the curvature of space in our observable universe. If some object flies behind the cosmological horizon, then it ceases to exist. Occams razor dictates that there is NOTHING behind the horizon.

Of course, you would say that A1 is true, and A2 is weird. Now compare:

B1. All branches predicted by the Quantum Decoherence exist. Why not?
B2. No, only one branch exist. Other branches are cut by the occams razor.

Login in A1 is exactly the same as in B1, and in A2 as in B2. You can chose A1 and B1, or A2 and B2 to be consistent.

Fra

Sep27-09, 03:28 PM

Could you list any predictions of the theory you prefer? I have an impression (may be I am wrong) that if that evolving law thing is true, on our way to the ultimate TOE we will get dissapointed by our inability to build a formal system which describes the Universe. Trying to find the TOE we would understand that no TOE is possible. End of physics...

I do not yet have a mature theory, but I can tell you what kind of "predictions" I expect out of such a program:

- effective unification of all interactions as the complexity of the inference system -> 0 - this would correspond to what in the standard language is the high energy limit. But there are some differences in that the normal high energy limit rather refers to the energy supplied from the context to the subsystem, my abstraction suggest that there is no unlimited source of energy, so the high energy limit gets a natural UV cutoff in way that is argued towards in a way that does not make use of black holes and other stuff. But I do expect a connection.

- A preferred way of breaking the unification as the complexity of the inference system increases from zero. This corresponds to going towards the low energy limit. Here is also a natural IR cutoff for each inference system, since the complexity is bounded.

- these cutoffs are rooted in the reconstructed measurement theory and has to do with resolution.

- A prediction of an action, can be done given an inference system, and thus the expected laws are system dependent, but the substantial difference from say string theory is that this approache should be immune to tragedies like the landscape issue because the diversity is constrained by the intrinsic information divergence.

- the selection principle of mutually consistent inference system should make predictions of the population of particular inference systems in nature; ie it should make predictionso of matter and particle contents and their actions, including their masses and so on.

- The relative masses and the hierarchy problem would I presume, be explained from the hierarchy of the information measures, and how it has evolved.

if that evolving law thing is true, on our way to the ultimate TOE we will get dissapointed by our inability to build a formal system which describes the Universe. Trying to find the TOE we would understand that no TOE is possible. End of physics...

If you think we will fail to fine and eternal TOE as a static thing like a fixed axiom systems, where we never have to remove or add axioms, I think you are right - it will fail.

But that's not a problem, because my focus is on understanding and making predictions of this evolving system.

In fact, IMHO, one key exploit here is that the reason for the action of the microstructure we see in the standard model of particle physics beeing what it is, is BECAUSE the particles participating in that interaction themselves don't have an ability to predict their own environment - this is reflected in their actions and INTERactions.

This is very far from end of physics, I rather think it would very much deepen our understanding of physics. Another level of "end of realism in physics" maybe, like we have seen suchs endings before with both Einsteins relativit and QM, we are still awaiting the next step I think :)

But I can't prove any of this of course. But it's just some of the expectations of such a program.

About other related predictions, Smolins CNS makes predictions on the maximum mass of neutron stars. Finding a neutron star more massive than the limit would falsify CNS.

/Fredrik

Dmitry67

Sep27-09, 03:35 PM

thank you for your reply.
I have another question
Is there an effective way to distinguish
1. MWI (everything happens) + AP (Anthrophic Principle)
from
2. Cosmic Darwinism
and from
3. Evolving law?

marcus

Sep27-09, 03:55 PM

Perhaps I've not considered well enough, but it seems to me that any measurement based curve fitting approach is inherently incapable of discovering the completion of physics. ....

It sounds like you are thinking about stuff that doesn't exist. I don't know of any purely curve-fitting approach to anything in physics. Ideas will always creep in :biggrin:
Could you be wrestling with a straw man named Mr. Curve-Fitting Approach?

I'm skeptical of your being able to find any branch of science where practitioners consistently follow any stated rulebook method, as if they were automata.

Maybe I shouldn't argue this anymore with you, Friend. You have your opinion about the Limitations of Science based on your own concepts and reasoning. I have a different set of aperçus. In the end all we could do is make predictions about, say, the next 15 years of research and (if we both survive that long) check later to see whose mental model was closer to the real world.

marcus

Sep27-09, 04:36 PM

...About other related predictions, Smolins CNS makes predictions on the maximum mass of neutron stars. Finding a neutron star more massive than the limit would falsify CNS.
...

thank you for your reply.
I have another question
Is there an effective way to distinguish
1. MWI (everything happens) + AP (Anthrophic Principle)
from
2. Cosmic Darwinism
and from
3. Evolving law?

Dmitry, that's a beautiful clear question. As Fra already indicated Cosmic Darwinism (the usual version is Smolin CNS) does make predictions. It predicts that you will not find a neutron star with mass substantially greater than 1.6 solar. And various other specific things. The general prediction is that you will not be able to find a Standard Model number that is not "hilltop" optimized for black hole production in the sense of being better than its nearby neighbors.

Anthropery does not predict anything quantitative. Whatever you measure in the future, whatever Standard Model number, it will automatically be consistent with our having lived and with our having measured it. Any possible physics discovery is consistent with life having arisen and learned how to investigate physics.

CNS was developed partly for the very purpose of providing a testable alternative to Anthropery. To show that you could construct falsifiable multiverse hypotheses. It is very different from the typical stuff about ManyWorlds, or StringLandscape, or EternalInflation and suchlike colorful fantasies which give infinite food for imagination without solid quantitative predictions.

Science theories can never be verified, only falsified. But if they pass tests a lot, they get tentative acceptance. If you want to know if we live in a CNS universe, the way to get a handle is to try and disprove it. Try to find a change in any of the 30-some numbers that characterize our universe which, if it were somehow implemented, would have resulted in more black holes.

The other thing you ask is how to tell the difference from Evolving Law.
I don't know of any definite Evolving Law hypothesis that can be tested!
I think it is unscientific and irrational to assume that there are eternal immutable laws---because we have no proof of that. All the evidence is that our knowledge is only provisional and the patterns we see are subject to revision.
To claim that there are eternal unchanging laws would be to assert much more than we actually know.

But I could not deny that proposition either. How could I, on what basis?

To answer your question I need to have some specific Evolving Law hypothesis. Some law and some mechanism by which it evolves. The only specific I can think of is Smolin CNS.
It conjectures that a law (the standard models of particle physics and cosmology, given by the 30 dimensionless numbers) changes slightly and evolves towards reproductive success, so that you expect hilltop optimality. That is a case of Evolving Law. But it is not so interesting to just have one sole case.

How about you think up another example, a different reproductive mechanism, a different optimization for reproductive success. A different optimality prediction about how the numbers should be. Then we could test.

Maybe someone else can respond, but I don't see how unless you give me some specific Evolving Law mechanism to examine and compare.

tom.stoer

Sep27-09, 04:44 PM

Tom, I have a tricky question ...

Dmitry67, I need time for the answer. In the meantime you can think about the following: Since God is all-powerful, can he create a stone too heavy for him to lift?

Tom

Fra

Sep28-09, 12:47 AM

I can think of several ways to comment on this. Marcus already provided some comments but there are some more.

Note: The obvious example of evolving law, that Marcus makes and also that Smolins makes is that it's a basic observation to note that what we humans have thought was physical law, has changes over the years. Now, the typical realist objection to that would be that we are confusing physical law, with our knowledge of physical law. But that objection is inconsistent with another hypothesis of mine, namely that physical action depends upon the inference system and the information at hand only. Ie. every system responds/acts upon the information it has only.

Ie. it's exactly the view that you CAN distinguish between information about a fact, and the fact itself, that is the difference between a realist and a nonrealist IMO.

I am saying that the physical action of a system is invariant to which.

thank you for your reply.
I have another question
Is there an effective way to distinguish
1. MWI (everything happens) + AP (Anthrophic Principle)
from
2. Cosmic Darwinism
and from
3. Evolving law?

I'll try to write more later, on my way to work.

But in my view of evolving law, which is a little different than CNS, the viability should come from several components.

Diversity from uncertainty; uncertainty is bounded and so is diversity - there are no inflated landscapes of unconstrained possibilities.

The selection and evolution of an inference system is implemented by means of feedback from the environment (the unkonwn) as subjective times progresses, and this forces the inference system to either revise or to face destruction. A property of self-preservation selects inference systems by fitness. But this is environment dependent, and what is fit depends on the environment. Therefor some interaction of inference systems must be considered to find a probable distribution of inference systems in nature.

Time is subjective in my view, but I disagree with rovelli in that I do not treat the system-system transformations as realist elements. These transformations themselves are emergent as the system complexity increases. A given finite observer, has a limit to how well it can infere the symmetries. In practice he will infere the symmetry, but it will be fuzzy. IE. the symmetry transforamtion itself is uncertain.

This is different than how smolin argues. I interpret smolin to take a little more conservative approach by considering variation of some known parameters. But you have to start somewhere, and I see smolins CNS as an interesting first attempt at something little more concrete, but not necessarily the final implementation of the vision.

Antrophics is mostly an attempt to save situations where you are sitting in a landscape of possibilities and are lost. Then you try to shave of possibilities by saying that the inferences that doesn't lead to what you know, must be wrong. It's a sort of post-diction kind of reasoning. It's a little related to the evolution but the major difference is that my idea of rational action; suggest a way FORWARD, given the present, not just a way from some speculative past to the present. The further conjecture is that all physical actions are constructed this way, and this insight can also help us understand the action of the standard model - that there is a yet not acknowledged logic to it's construction, that is not just geometrical inspiration, it's rather inspired by a new inference model.

If you look at say the path integral, the association is clear that it seems that the physical action is construced by "considering" various options AS PER some specific inference system. I am convinced for more than the similarity reason that this is not a conicidence at all. There is something deep about inference and physical actions that is not yet acknowledged. For ME at least (not sure about smolin) I see this strongly linked to the concept of evolution of law, since the inference system itself is also subject to change. Picture the path integral or a generalisation thereof as a computation, then there is a computer (matter) and and action that is induced from the result of the computation (action) and a feedback from the environment (reaction) that gives feedback to not only the computation but also to the computer.

/Fredrik

moniker2

Sep28-09, 01:44 AM

thank you for your reply.
I have another question
Is there an effective way to distinguish
1. MWI (everything happens) + AP (Anthrophic Principle)
from
2. Cosmic Darwinism
and from
3. Evolving law?

Here you go, but it comes from an unreliable source.

m = [f / {[(1/(1-(v ^2 /c ^2 )) ^1/2 ]-1}a
This makes many assumptions but the most intriguing is the imaginary units of mass.

tom.stoer

Sep28-09, 02:38 AM

Tom, I have a tricky question regarding the Occams razor ...

So, it is very likely that our universe is infinite. As we know, the expansion is accelerating, so there are cosmological horizons: we will never ever be in causal contact with some distant areas of our universe.

My question is: do these areas really exist?

Dmitry67! yes, they exist - and again Ockham's razor is on my side.

First I have to explain what the principle of Ockham's razor really means: It essentially says that that "entities should not be multiplied unnecessarily; when you have two competing theories that make exactly the same predictions, the simpler one is the better": http://math.ucr.edu/home/baez/physics/General/occam.html
So it does not say that the theory that contains less entities is better, but the theory that provides the simpler explanation of known facts is better.

Now let's look at the expanding universe with horizons. A certain area of space which resides inside our horizon does exist (I hope we can agree on that). Now due to the (accelerated) expansion this area disappears beyond the horizon. The two competring theories are:

1) the area of space still exists but becomes invisible
2) the area of space ceases to exist

Both theories should be based on spacetime and should be compatible with the framework of GR; this means they have a common basis and are of the same complexity. Now the phenomenon of the horizon may add some new entities which are subject to Ockhams razor.

In theory 1) you have to explain what the horion is: it is a geometrical concept that is somehow build-in. There is no extra ingredient or entity besides the fact that you observe accelerated expansion. But that is not really new as it is derived from observation and not from theoretical constructions. The area of space beyond the horizon is no new ingredient, either, as it already existed before it went across the the horizon.

In theory 2) there will be one new ingredient or entity, namely an explanation how a certain area of space plus all matter, energy etc. can cease to exist. You have to provide a process, a formula or something which tells us what happens to all the stars, galaxies etc.

Look at a room with a huge library. Lock the door and throw away the key. Are the books still "there"? I would say "yes" ...

Dmitry67

Sep28-09, 03:30 AM

Dmitry67, I need time for the answer. In the meantime you can think about the following: Since God is all-powerful, can he create a stone too heavy for him to lift?

Tom

Definitely God wont be able to lift such stone without help of Max Tegmark :)

Dmitry67

Sep28-09, 03:40 AM

1
First I have to explain what the principle of Ockham's razor really means: It essentially says that that "entities should not be multiplied unnecessarily; when you have two competing theories that make exactly the same predictions, the simpler one is the better": http://math.ucr.edu/home/baez/physics/General/occam.html

2
In theory 2) there will be one new ingredient or entity, namely an explanation how a certain area of space plus all matter, energy etc. can cease to exist. You have to provide a process, a formula or something which tells us what happens to all the stars, galaxies etc.

1 Yes, we both agree on the definition of Occams razor. We dont agree on the definition of 'entity'. A HOLE or a VOID in substance - it is an ENTITY?

For me IT IS, because it breaks the symmetry and injects new information into syste,

2 Yes, definitely yes!
So you can apply the same logic to MWI branches - it is logical to say that they do not cease to exist. Once we accepted Level 1 and Level 3 multiverse, it is easier to accept Level 4 multiverse.

Dmitry67

Sep28-09, 03:47 AM

It predicts that you will not find a neutron star with mass substantially greater than 1.6 solar.

Could you explain, why? My problem is that my disagreement with Smolin is so strong that I would hardly be able to read anything to the end.

Fra

Sep28-09, 04:28 AM

Could you explain, why? My problem is that my disagreement with Smolin is so strong that I would hardly be able to read anything to the end.

You can read smolins papers, but the basic idea is that smolins conjecture is that our universe must be (or is highly likely to be) optimized for black hole production. The reason for this is that in Smolins CNS idea, a universe that produce no black holes would be steril and unable to produce "offsprings" (with or without variation).

Now smolin has argued that a universe that is so constructed, for optimal black hole production would not host arbitrarily massive neutron stars. "Ie. if the parameters of the laws of physics are so as to optimise black hole production, then there is a limit on neutron star mass."

I think that is the simple general idea. If you want to see the details, or verify that this is a correct inference I think you need to dig into Smolins papers.

But before you look at his specific CNS, I would suggest listening to his general arguments against eternal law first, because it's possible to have objections to CNS but still appreciate the general idea(http://pirsa.org/08100049). To jump into a specific suggestion before appreciating the general idea is I think harder.

I am not overly fond of CNS which I see as a first, probably simplest possible, attempt to realise the idea into something a little more concrete, but I share his general objection to eternal law.

/Fredrik

Dmitry67

Sep28-09, 05:27 AM

Thanks. Why production of the Black Holes is so important?
Because he thinks that they give birth to other Unvierses, implementing the Cosmic Darwinism?

But if the Goal function is the number of universes/black hole, then it does not explain why do we exist. You can have a very successful 'universe factory', but all these universe can be strile. Say, no elements heavier then He, but manymany many black holes.

That idea would be much more interesting if the creation of Universe would require so rare conditions that it would require an intelligent life. That would be an alternative to AP. In the current form, it just explains why there are many universes, but you still need AP to explain, why at least some of them are life-friendly.

tom.stoer

Sep28-09, 05:52 AM

Dmitry67,

what do you think: do the areas beyond the horizion exist?

Dmitry67

Sep28-09, 06:08 AM

Dmitry67,

what do you think: do the areas beyond the horizion exist?

Yes, like the alternative branches in the MWI
I think on our way to TOE we have to give up the falsifiability...

ConradDJ

Sep28-09, 07:18 AM

Biological evolution is based on fundamental laws (DNA) which are not subject to the evolution process itself but provide a fixed, external system.

Tom – This is profoundly incorrect. The DNA code certainly did evolve. There are many regularities in biology, but none of them have the character that physical laws seem to have, as “a fixed, external system” of changeless laws governing how things change. All of them derive from an evolutionary process, the only “law” of which is just – whatever manages to reproduce itself, manages to reproduce itself. Everything follows from that.

Your earlier statement was more sensible:
My conclusion is that it is not sure that dynamic processes require dynamic laws. Far from it, progress in science tells us that in many cases the underlying laws of dynamic processes are static laws.

The word “dynamic” here is ambiguous. It’s very important to distinguish between physical laws (A) changing over time and physical laws (B) evolving, in a sense that’s comparable with the biological case.

(A) It’s certainly possible that some things we take as changeless laws of physics – the gravitational constant, for example – have actually changed over time. The whole development of cosmology over the past century has shown us how much more dynamic the universe is than anyone had expected. But this is not evolution in the significant sense, comparable to biology. If something in the structure of physical law can be meaningfully said to have changed over time, then that must have happened in the context of a “fixed, external system” – as you said – which doesn’t change. “Change” only has meaning if there is a context that is at least relatively changeless.

(B) When we talk about the laws of physics evolving, we’re talking about the “fixed, external system” itself and where it came from. Even in Smolin’s CNS – which I don’t buy at all – within any given universe, the basic laws of physics are still changeless. It’s only in the process of creating one universe out of another that they change. (And the weakness of Smolin’s idea is just that it has nothing to say about how this reproductive process happens, or why it would result in universes with different laws, or most important, why the laws in a “child” universe would be only a little bit different from those of its “parent”, which is critical to making an evolutionary process work).

In my view CNS is a way-too-literal attempt to apply the biological evolutionary theory to physics. If there is an evolutionary process underlying the laws of physics, I don’t think it’s based on self-replication. In the physical world, self-replication is very hard to achieve – which is why life is so rare in the universe.

On the other hand, I’ve tried to make the point in other threads that there is a “process” that’s as ubiquitous in physics as the reproductive process is in biology – namely what we call “measurement” or “observation” or just the “communication of information” between physical systems. This is harder to envision than self-replication, because it’s not about the multiplication of physical entities (organisms) but about the multiplication of “measurement-events” between entities. And of course the whole issue of the role of “measurement” in physics is tremendously confused.

I won’t go into the reasons why I think communicating systems can evolve via “natural selection” much the way reproducing systems can. But I want to emphasize again that this is not necessarily about some or any of the laws of physics being “dynamic” in the sense that they could be observed to be different at different historical times. That may or may not be the case, but it’s a different issue.

Here’s the thing – the laws of physics we observe now, in our well-established theories, let us look back in time and learn a great deal about the very early universe. But everything we’ve learned about it teaches us that for hundreds of thousands of years after the “beginning”, the physical conditions of the universe would not have supported any way of measuring or observing those laws. Before the emergence of atoms, it may well be that no definable information could have been communicated from one physical system to another.

I’m not saying our theories about the early universe are wrong – just that these theories are only meaningful if there are physical systems that function as “clocks and measuring rods”, etc. And the theories tell us that there was a time when no such systems existed anywhere.

So the early universe as we see it now, based on present-time data, is the early universe as communicated through a very different and far more elaborately structured informational environment than used to exist in our universe.

The point is that the laws of physics may or may not have changed over time, but clearly they did become meaningfully definable in the course of time. And it seems reasonable to ask about which aspects of these laws became physically determinable first, and which later on – and whether this sequence may reflect an underlying evolutionary process. And we should probably consider time itself as one aspect of the structure that evolved in this sense, not as a “fixed, external” background within which this process occurred.

If you appreciate how powerful the evolutionary principle is in biology – i.e. how much can be explained about living systems without having to make arbitrary, unexplainable assumptions – then I think it will seem worthwhile to pursue any avenue that might lead toward a similar principle for physics.

Fra

Sep28-09, 07:40 AM

Tom – This is profoundly incorrect. The DNA code certainly did evolve.

Indeed. Not only did the DNA CODE evolve, but the structure for the code as wel (compare microstate vs microstructure), this is I think the even more important point.

I objected to this to Tom before as well, in post#209 in the same thread.

Tom's response was to dismiss this flawed analogy beeing off point. But I think it's very much to the point.

If we picture a configuration space of all possible DNA sequences, then the point is that not only does dna sequences evolve, within the space, the more profound point is tha the "configuration space itself" has an origin.

This is the deeper point that Smolin also tries to explain in his motivation for evoling law. The configuration space bounds the questions you can possibly pose, therefore new possibilities arise and the configuration space changes. The alternative would be an infinite totally out of control infinite configurations space that would drown any computation. Not to mention that we run into the same old problem of having to accept an utterly even infinitely unlikely initial condition.

Weird as it seems but the evolving law idea actuall solve a lot of problems too; fine tuning problem and the problem of initial conditions etc.

/Fredrik

tom.stoer

Sep28-09, 07:51 AM

I would like to make clear that when I am talking about "dynamically changing laws" I definitly mean changes in the sense of "evolution of laws". Sorry for the confusion.

It is clear that "trivial changes" like the value of a "constant" might be explained by some deeper, fixed theory (string theory suggests dynamically changing constants as they are expectation values of certain fields). So what we are really interested in is the question if these deeper theory itself dissolves in some "evolution process" and dynamically changing w/o being grounded again on some deeper, fixed structure.

I appreciate the discussion regarding this possibility, but I think I already made clear that - for various reasons - I do not believe in this theory.

Regarding the applicability of laws at earlier times that we derive currently: it compares to the area that hides beyond the cosmic horizon. If a theory explains experimental results in some domain (time, space, energy range, ...) then we try to extrapolate beyond this domain. This is what usually happens in physics (or science in general): we believe that planetary orbits exist in distant galaxies, even if they are not measurable. We even believe that if a planetary system forms from interstellar dust then the new planets follow the same well-known planetary orbits. Therefore we extrapolate in timelike as well as in spacelike direction.

In biology it should be clear that the laws of evolution do exist even before the first DNA molecule was formed. That means that the existence of these laws (as they are based on chemical and physical laws as well as on mathematical ones) transcend their application. I believe that the same is true in physics.

w/o this principle science would not be possible at all, simply because it would restrict the domain of validity of laws to the domain of their application. That would mean that predictabiliyt gets lost as we are simply not allowed to predict the result of an experiment before we have collected and evaluated the data.

So my credo is: Science forces us to believe in laws transcending their application

tom.stoer

Sep28-09, 08:00 AM

Tom – This is profoundly incorrect. The DNA code certainly did evolve.
I do not talk about the evolution of a collection of DNA molecules but about the evolution of the laws of the DNA code. There is no such evolution! The chemistry of DNA was, is and will be fixed forever. If DNA molecules are crossed, changed, if there are DNA defects or if they are dying together with their phenotype doesn't matter.

The same applies to the laws of physics. If in a far future all physical objects in the universe fade away in a "Big Whimper" doesn't affect the laws for planetary motion. As already indicated I somehow like structural realism which says that the Kepler orbits (as laws) do exist even if the planets (as materialization) cease to exist.

Dmitry67

Sep28-09, 08:10 AM

Tom, there are 2 versions of the DNA code: old one (ribosomal DNA - rDNA) and modern (DNA in all other cells - mDNA). So DNA code did evolve. Ribosomal DNA code looks similar to the modern one, but some codons are interpreted there differently.

But I agree that laws do not evolve.

tom.stoer

Sep28-09, 08:15 AM

OK, fine. You found weakness in my biological reasoning :-)

No problem: The changes in the laws of the DNA code are explained on the basis of eternal laws of chemistry.

ConradDJ

Sep28-09, 08:25 AM

Regarding the applicability of laws at earlier times that we derive currently: it compares to the area that hides beyond the cosmic horizon. If a theory explains experimental results in some domain (time, space, energy range, ...) then we try to extrapolate beyond this domain. This is what usually happens in physics (or science in general): we believe that planetary orbits exist in distant galaxies, even if they are not measurable... Therefore we extrapolate in timelike as well as in spacelike direction.

Yes – and this is difficult to make clear, because of all the confusion about measurement in QM – but I would argue that there is an important difference here:

1. Does the other side of the moon exist? Or does a planet exist before someone observes it? Or beyond the cosmic horizon?

2. Does an electron have a definite position, in a context in which its position it is not determinable by any interaction?

My point is that the situation with the early universe could well be more like 2. than 1. In the first case, whether there determinate information is available or not depends on someone’s perspective. In the second case, it’s a matter of the structure of the laws of physics themselves, that allow some things to be measurable in certain circumstances, and not others.
In biology it should be clear that the laws of evolution do exist even before the first DNA molecule was formed. That means that the existence of these laws (as they are based on chemical and physical laws as well as on mathematical ones) transcend their application.

w/o this principle science would not be possible at all, simply because it would restrict the domain of validity of laws to the domain of their application. That would mean that predictability gets lost...

Again, this is a misunderstanding. There are no “laws” of biology in the sense that there are “laws” of physics. And indeed very little can be predicted in biology, though that doesn't disqualify it as "science". And in comparison with physics, the extent to which what happens in biology can be understood – after the fact – is quite remarkable. The explanations are essentially historical -- they don't refer back to fixed, changeless principles that apply in general, but to the specific circumstances in which something arose.

In physics, prediction is very powerful, just because so much can be understood in terms of changeless mathematical laws that apply to everything, at all times. On the other hand, the Standard Model remains so complex that to me it makes sense to look for a way of understanding why these laws and principles are the way they are... as we’ve discussed above. The model favored by most physicists is the traditional one -- look for more general principles from which those of the Standard Model can be "predicted". The quest for that kind of TOE has gone on for quite some time now, and it's hard to say whether it's closer to success than it was a few decades ago.

So this is why I think the very different scientific model of biology may turn out to be useful. Needless to say, there's room for disagreement!

Dmitry67

Sep28-09, 08:29 AM

Again, this is a misunderstanding. There are no “laws” of biology in the sense that there are “laws” of physics. And indeed very little can be predicted in biology, though that doesn't disqualify it as "science". And in comparison with physics, the extent to which what happens in biology can be understood – after the fact – is quite remarkable. The explanations are essentially historical -- they don't refer back to fixed, changeless principles that apply in general, but to the specific circumstances in which something arose.

In MWI, or if our Universe is infinite in space, then everything which might happen happens. Then we can give - in some cases - accurate predictions of the evolution (of course, statistically on huge number of planets)

Fra

Sep28-09, 08:55 AM

No problem: The changes in the laws of the DNA code are explained on the basis of eternal laws of chemistry.

I still insist there is something that you miss with this reduction, and it's complexity.

But the reductionist approach you advocate, the problem is that the information capacity and "computation power" need to implement this is massive. And unless this information and computation capacity is at hand, your reductionist approach fails.

Why doesn't biologist simply do numerical simulations of biological spieces from complex molecular and atomic mechanics? The complexity neede for that approach fails. Rounding errors and all kinds of chaotic problems makes this strategy inviable.

I'll rephrase the question I ask to make my point more clear: The question is howto predict the future, given the present (including retained parts of the history), but the constraints are also that we have finite representative capacity and computation power - thus an idea that in absurdum might work, but requires more information capacity and computational power than we actualyl have at hand, simple is of no use.

Thus, the theories themselves must "scale", this is what I think of as scaling the inference systems. The inference you picture, by the extreme reductionist approach (explain life from the laws of chemsitry) fails because these inference system gets a complexity that isn't physical.

Another example, an algorithm or computer code, written for one cpu, needs to be "scaled" to run on a smaller cpu wit less memory. For the case of physical law, I think this scaling can be nontrivial, it's not just averaging. It's also the reverse problem on howto scale up, this requires evolution as more information is added and needs to be tuned.

/Fredrik

tom.stoer

Sep28-09, 09:30 AM

1. Does the other side of the moon exist? Or does a planet exist before someone observes it? Or beyond the cosmic horizon?

2. Does an electron have a definite position, in a context in which its position it is not determinable by any interaction?

My point is that the situation with the early universe could well be more like 2. than 1. In the first case, whether there determinate information is available or not depends on someone’s perspective. In the second case, it’s a matter of the structure of the laws of physics themselves, that allow some things to be measurable in certain circumstances, and not others.

The difference is not only that something may depend on someones perspective. The difference is - in addition - that in the first case the question is if some entity EXISTS whereas in the second case the question is if something HAS a specific PROPERTY or VALUE.

No it is certainly not the same level of existence in the two questions
if THE (OTHER SIDE OF) MOON EXISTS or
if A VALUE TO BE MEASURED EXISTS before the measurement process.

In the case of the electron there is (at least for me) no problem that there exists an entity called "electron" w/o having a certain property.

tom.stoer

Sep28-09, 09:41 AM

But the reductionist approach you advocate, the problem is that the information capacity and "computation power" need to implement this is massive. And unless this information and computation capacity is at hand, your reductionist approach fails
I don't think so. The EXISTENCE of something (entity, law, ...) need not depend on the possibility to IMPLEMENT it. It could very well be that the complexity of the universe forbids its implementation or simulation.

Compare it to mathematics: the real numbers form an uncountable set, computer programs or algorithms form a countable set. Using algorithmic complexity as a condition for existence would mean that almost all real numbers do not exist.

Attention: My approach is not a reductionist one. I do not say that I can explain life with all its emerging properties from laws of chemistry. The latter one serve as a basis only. Look at language: assume for a moment that the English language would follow strict, logical rules. Do you think that would preclude literature to exist? Certainly not.

Fra

Sep28-09, 10:30 AM

I don't think so. The EXISTENCE of something (entity, law, ...) need not depend on the possibility to IMPLEMENT it. It could very well be that the complexity of the universe forbids its implementation or simulation.

I know we differ here, but to me your notion of EXISTENCE is almost a non-physical and non-scientific one. I think it's because ou are more realist than me but from my point of view your question "does it exist" without considering how it's inferred, simply has no impact on the actions - which is the prime concern to me.

/Fredrik

friend

Sep28-09, 11:58 AM

It sounds like you are thinking about stuff that doesn't exist. I don't know of any purely curve-fitting approach to anything in physics. Ideas will always creep in :biggrin:
Could you be wrestling with a straw man named Mr. Curve-Fitting Approach?

I'm skeptical of your being able to find any branch of science where practitioners consistently follow any stated rulebook method, as if they were automata.

Maybe I shouldn't argue this anymore with you, Friend. You have your opinion about the Limitations of Science based on your own concepts and reasoning. I have a different set of aperçus. In the end all we could do is make predictions about, say, the next 15 years of research and (if we both survive that long) check later to see whose mental model was closer to the real world.

Can you give me an example where the methods used are NOT curve-fitting. Yes we extend our models by trying to generalize the math and see if it's applicable. But how is that conceptually any different than finding the next term in a polynomial expansion in order to better match a curve? I mean even looking for gauge symmetries is just a means of trying to more easily find functions that match the data. Even string theory was first considered because it was math that seemed to closely match some nuclear physics. Yes, this may produce results. But it can never produce a TOE because you'll never know if it's not possible to find greater generalizations that might apply; let's add another term to the expansion and see what we get. What kind of creative thinking did you think we were doing?

Fra

Sep28-09, 03:31 PM

thank you for your reply.
I have another question
Is there an effective way to distinguish
1. MWI (everything happens) + AP (Anthrophic Principle)
from
2. Cosmic Darwinism
and from
3. Evolving law?

One would have to admit that "evolving law" is currently not a specific theory. It's IMO first of all a new way of thinking, that takes a while to get used to. And it might possibly define a new direction for research programs.

Smolins CNS cosmic darwinism is one possible realisation of evolving law.

But the major difference between CNS and what I envision is that I do not think diversity and selection takes place isolated in black holes, I think it takes place everywhere. The difference between predictable time evolution as per some laws of dynamics and the not so predictable evolution of laws, are simply two extremes of the same scale.

I try to combine the ideas of laws of physics following from rules of inference, with the evolving law concept. It's a mix of smolings evolving law, and ariel catichas and jaynes idea to "derive" the laws of physics from an extension of logic.

The purpose of of the evolution in this context (this is how I think of it, not smolin an his CNS) is to bridge the problems of the rigid logic systems, regarding proving completeness etc. Tom was acknowleding this, but has not yet given up the idea it seems. I have come to the conclusion that an evolving inference systems is a possible way to do. I have great personal confidence in this, but it's a very complex undertaking, and it's probalby not realistic that one person should start from this point, and complete the reconstruction up until the standard model level.

This is why I think ALL research that are more or less in this direction is very interesting and important.

MWI and AP doesn't even enter the same level of ambition for me, so distinguishing them from the two others seems obvious. MWI is an interpretation of QM - I am suggesting a reconstruction of the entire formalism of QM, by deeper insights in intrinsic information theory.

note: In fact, from the way I reason, taking an intrinsic inference perspective seriously, the evolution is even a prediction becase there is no static solution. So I do not "assume" ad hoc that parameters vary randomly and there is some undefined selection, I rather think that the evolving inference system follows from the self-constructive inference itself. Successful parts are reinforced by a kind fo statistical weight, and inconsistent parts and eventually diluted and eventually become indistinguishable and are erased. What I am fighting with is to make this precise, and then the next step is of course to extract the physics we are used to - to reproduce 4D spacetime and matter content. The matter content in my view IS the inference system population. This is definitely not what smolin is thinking - it is a clear mix of smolins GENERAL idea, AND the program of physical inference (ariel caticha, et jaynes etc).

There is a synthesis of these two ideas to be made. Since few seems to bother with this I see no better option but to try to do it myself, although it's an overwhealming task.

/Fredrik

tom.stoer

Sep29-09, 12:35 AM

I know we differ here, but to me your notion of EXISTENCE is almost a non-physical and non-scientific one ... from my point of view your question "does it exist" without considering how it's inferred, simply has no impact on the actions - which is the prime concern to me.

Let me ask one question again: Go to a room with a huge library, lock the door and throw away the key. Do the books continue to exist?

From your last postings I would say that you position is very close to idealism. Of course I can't prove that it's wrong, but you certainly run into trouble that you have to explain how your approach differs from pure subjectivism.

It seems to me that your position is always jeopardized to become non-scientific.

Fra

Sep29-09, 12:50 AM

Ok, this is a simple example but let me put it to make me point more clear.

Let me ask one question again: Go to a room with a huge library, lock the door and throw away the key. Do the books continue to exist?

If we suppose that this is the door to another world, and that the door is irreversibly closed. Then to be honest, I would never raise the question - I would probably be better off investing my time in posing a more constructive question.

Do the books still exist in the world I will never be able to communicate with? I honestly would be completeley indifferent to which :)

However, if there was still interactions with that room, and there was mechanisms where the books beeing there or not, would influence my future, then I would take into consideration that the books exists or not exists, when inferring the possible future of mine, and it would also influence my action! And if we are talking about a macroscopic library then the mass of that makes it very probably that the information I received when the door was open, does not change immediately as I close and lock it.

So my answer is that the existence of the books is meaningul only if there is to me, an distinguishable mechanism for how it might influence my future. Otherwise I would not waste my time pondering about wether god is left or right handed, because I am completeley indifferent to these things. There is no basis at all for rising such question.

From your last postings I would say that you position is very close to idealism. Of course I can't prove that it's wrong, but you certainly run into trouble that you have to explain how your approach differs from pure subjectivism.

I think I've tried to explain this. In my view, objectivity is emergent as a RESULT of interactions and selection on the subjective inferenc esystems. This is a very important point.

My view of symmetry is for example NOT that there in a realist sense exists a set of subjective/relative views that happen to have a certain transformation wich generates all of them. And the symmetry is again of realist type. (this is the COMMON view)

Instead, but view is that as a subjective inference system is put to interactions, the local group of interacting subjective inference systems will exert ON THE OTHERS a selective pressure that causes emergence of a local symmetry. However this symmetry has not global meaning beyond this local group of interactors.

I understand that on first glimps this may sound like anything goes etc, but that's not the case. The trick is the evolutio and selection. "Anything goes" simply doesn't survive the competition, a system needs to be in consistency with it's local environment to be in local equilibritum. About global equilibrium, there is no local definition of such a think. To make a very large scale equilibirum, you need a Very very complex and massive observer.

/Fredrik

tom.stoer

Sep29-09, 02:24 AM

If we suppose that this is the door to another world, and that the door is irreversibly closed. Then to be honest, I would never raise the question - I would probably be better off investing my time in posing a more constructive question.

Do the books still exist in the world I will never be able to communicate with? I honestly would be completeley indifferent to which :)

However, if there was still interactions with that room, and there was mechanisms where the books beeing there or not, would influence my future, then I would take into consideration that the books exists or not exists, when inferring the possible future of mine, and it would also influence my action!

OK, let's discuss this in the context of cosmic horizons. An area A of space that disappears from our "world" beyond the cosmic horizon will certainly no longer interact with you (your area X). But of course there are other distant areas B, C, D, ... still visible to you which can interact with area A. Therefore the EXISTENCE of area A does not only (as far as I can see) depend on the interaction with area X, but on the interaction with B, C, D, etc. Keep in mind that it is by no means clear that the interaction of X with B, C, D will (in the far future) be communicated to X. In a typical scenario with horizons these signals from B, C, D will be hidden in the future behind the same expanding horizon and will NEVER be received in X.

That means that you have to give up the subjective perspective and believe in the objective world telling you that other areas of space will "support" A to continue to exist.
So in some sense A ceases to exist from a subjective point of view, but it will continue to exist from an objective (or realistic) point of view.

This is exactly the consequence of Berkeley's idealism. He was very clear about the fact that if you assume that only "observed phenomena" are existing, then you have to explain how things can exist even if nobody is looking. As Berkeley was a bishop he trusted in good to observe everything in the universe and keep it existing.

What I am saying is that if your ontology is based on "your possible future, and influence on your actions", then this is essentially idealism. Your judgment regarding existence of certain entities is either subjective or incomplete. As you certainly want to avoid subjectivism you have to overcome incompleteness. You doubt that this will work w/o reference to any externally existing entity (material objects, laws, ...).

Fra

Sep29-09, 04:24 AM

I'll get back later and try to elaborate about completeness, existence etc. I'm currently running low on time but i'll return with comments evenetually.

But in short, the completeness of percection you seen to seek, are not physically realisable. BUT you are right that seeking it is rational, but the process itself involves time and resources. This is exactly why there is evolution. Time is even a consequence of this failure to capture eternal perfection in a moment of time.

But more later... I'm stuffed with work atm

/Fredrik

Dmitry67

Sep29-09, 08:47 AM

Fra

Sep29-09, 11:47 PM

On my way but some more meanwhile..

Mmm you seem as obsessed with "existence", as I am with "inference", not sure what to say here...

I assume your argument is that the subjective view is different from your imagine objective view? Sure, but so what? I mean, what physical impact does this have? You seem to think it's a logical inconsistency, as it breaks your realist logic, that every question, even the ones that aren't asked, must have a definite - observer independent/inference independent - answer?

In my view, the "inconsistencies" actually imply physical interactions, in the sense of a selective pressure in the evolution.

This is what you do in symmetry arguments as well, that two choices of a gauge, imply an physical interaction. The difference is that I apply the inference also to the symmetry transformation itself, so we get an hierarchy of information.

That means that you have to give up the subjective perspective and believe in the objective world telling you that other areas of space will "support" A to continue to exist.
So in some sense A ceases to exist from a subjective point of view, but it will continue to exist from an objective (or realistic) point of view.

This is exactly the consequence of Berkeley's idealism. He was very clear about the fact that if you assume that only "observed phenomena" are existing, then you have to explain how things can exist even if nobody is looking. As Berkeley was a bishop he trusted in good to observe everything in the universe and keep it existing.

I'm not sure I follow your reasoning here. That something is indistinguishable from the point of view of observer 1, does not mean we can infere there is nothing there, it only means we know noting of it, and this unkonwn also does not influence our actions in a distinguishable way.

That's enough for me, I don't understand why you keep insisting in want to konw what you can't know, when it's indifferent to you?

I'm not one single bit religious :)

Your judgment regarding existence of certain entities is either subjective or incomplete. As you certainly want to avoid subjectivism you have to overcome incompleteness. You doubt that this will work w/o reference to any externally existing entity (material objects, laws, ...).

Incomplete? Of course there is a limit to my predictive power of the future - for several reasons, that is the whole starting point. It's the basic observation that is the starting point for it. My whole approach is based on inference based upon incomplete information. But the intrinsic form of this, is not like standard information theory, where you can exactly quantify what you don't know, instead you simply act on what you know, period. It's a game, the choices are to play or not to play.

If you are considering a realist view, where the information exists in some external sense, and in this birds view you can explain the incompleteness of the inside view, then it's not intrinsic inference.

Actually in my view, the external inference model DOES apply, when you as a large observer study small subsystems, because then you can physically justify at least an emergent EFFECTIVE birds view.

But this is a special case. Looking at your remote horizon is not a subsystem which environment you cna monitor.

This is - IMHO - why a new "evolving" logic is needed.

/Fredrik

tom.stoer

Sep30-09, 04:35 AM

I'm not sure I follow your reasoning here. That something is indistinguishable from the point of view of observer 1, does not mean we can infere there is nothing there, it only means we know noting of it, and this unkonwn also does not influence our actions in a distinguishable way.
I just responded to the following statement
If we suppose that this is the door to another world, and that the door is irreversibly closed. Then to be honest, I would never raise the question - I would probably be better off investing my time in posing a more constructive question.

... I don't understand why you keep insisting in want to konw what you can't know, when it's indifferent to you?
I do not insist that I want to know something about a certain entity, but I am insisting on the fact that my examples point into the direction that talking about existence of some entity must not only be based on its affect it has on your actions. If you restrict the meaning of existence to "is observed" or "has an affect" then you have to answer the question "who is the observer?" or "who is affected". With my examples I try to show that restricting to you as an observer may not be sufficient because then some entity that existed in some sense may cease to exist because of your horizons. That means the existence of this entity relies on "external observers" which essentially saves us from idealism (solipsism). I hope this clarifies what I mean by "incomplete".

One remark: I think the discussion is still interesting and we continuously uncover new aspects. But finally it always boils down to the fundamental different perspectives we have. I only want to make clear that I appreciate your reasoning! It's not that I am blind or ignorant, it's only that I see (from my perspective) certain obstacles in changing to the "dark side". So if you still like the discussion it's fine for me; if it becomes boring or if you think that we start to go round in circles then let me know.

Thomas

Fra

Sep30-09, 02:46 PM

With my examples I try to show that restricting to you as an observer may not be sufficient because then some entity that existed in some sense may cease to exist because of your horizons. That means the existence of this entity relies on "external observers" which essentially saves us from idealism (solipsism). I hope this clarifies what I mean by "incomplete".

Ok, if I understand you right which I think, the yes, we have "incompleteness". Agreed.

Now what I suggest is that this incompletness is no arfitfact due to a my flawed reasoning (like I think you think?) - it is a physical incompleteness to me, consistent with all I know. That's my point, and this incompleteness in any inference system, has measurable consequences in the actions.

I think it's also responsible for the arrow of time.

It is correct in a sense that my reasoning is unstable! It's just that from a realist view it is not unstable, it's incomplete and possibly inconsistent.

I'm suggesting instead that the instability has a direction, the subjective arrow of time. In this "flow" evolution of law are the slowest changes in the hiearchy and hardest to predict, the most vibrant "flow" is the ordinary time, that is flowing respect to the lower level states.

This is of course just a vision, but it's how it should work in detail when I get this worked out.

One remark: I think the discussion is still interesting and we continuously uncover new aspects. But finally it always boils down to the fundamental different perspectives we have. I only want to make clear that I appreciate your reasoning! It's not that I am blind or ignorant, it's only that I see (from my perspective) certain obstacles in changing to the "dark side". So if you still like the discussion it's fine for me; if it becomes boring or if you think that we start to go round in circles then let me know.

I know :) I'm not blind either, in a certain sense I do see your points. I guess I wanted to explain how the weaknesses you see, are handled in my view.

In a nutshell we do seem to get back to the deductive systems. From the point of view of deductive reasoning, my stance IS inconsistenct or incomplete. You conclude from within that system that my view is thus "probably" wrong? Does that sound fair?

Insteaf from My point of view, this inconsistency and incompleteness are real and physical, and instead the problem is the deductive inference system! If we instead take on an inductive type of inference, inconsistencies are not fatal, they just cause the inference system itself to revise.

I think like this:

The problem with your approach is that is risks to come to a halt, or simply fail to make progress in a rational way. The advantage is that it's more definitive, and not as subjective, and inferences are certain.

The problem with my approach is how to make sense out of this subjective mess. The advantage is that it does not easily come to a halt and it' a builtin deadlock avoidance since inconsistences are handled be evolving hte inference system which inferred it! Thus inconsistencies are interpreted as a need to revise the inference system itslelf.

I have tried to defined the motivation for why the deductive fixed axiomatic model are likely to fail, and motivate a search for a more flexible framwork. I also have at least tried to argue how I handle subjectivity. When two rational solipsists interact adn communicate, they will come to a consensus, a kind of emergent objectivity, but this objectivity has meaning only to the interacting parties.

/Fredrik

tom.stoer

Oct1-09, 12:22 AM

Thanks for the excellent summary!

John86

Oct1-09, 04:35 AM

Fra

Oct1-09, 01:32 PM

Hello Fra,

I am following this thread for quite a while now, and find your ideas really inspiring and usefull in more than one way. Subjectivism an evolution of physical law sounds very reasonable to me. But what role does Non-locality play in your ideas ?.

Hello John. I'm glad to be of some inspiration :)

Usually locality or non-locality refers to spacetime and distance. In my view, spacetime is emergent but there is a sort of locality principle that is can be defined prior to the regular spacetime.

I could it phrase it so that the principle is simply that the physical action of a system depends only from the evidence encoded in it. Thus there is "locality" in the sense where you envision a distance measure in "hypothesis" space, where the action weights possibilities in accordance to their respective confidence level. Thus, things with low or zero confidence level, has low or zero impact on the action.

Edit: I don't think I explained this well. I want to point out that I distinguish between action and reaction. The reaction is the backreaction from the environment following the systems action. This together gives evolution. So the action, is not a global action, it is only defined differentially so to speak. The action defines a differential change; it does not define the definite change since this involves evolution which has an undecidable part that is due to physical incompleteness.

In fact, this type of distance measure beeing a kind of information divergence, is a possible hint to how spacetime can emerge. Ariel Caticha (which is not as radical as i am, but still) has turned the coin around and suggest that instead of saying that things that are remote from each other are unlikely to influence each other; that things that as a matter of fact appears to have little or no influence on each other, and pretty much no correlation defines a distance, this way one can define distance in information space.

Some technical details though is that there are different ways to do this, there is also a standard topic (information geometry) where there are information theoretic origns of the metric. I picture it differently, that gives a more weird and "subjective" geometry, but then that advantage it's exactly the subjectivee view of the geometry that implies interaction forces. I consider a intrinsic kind of information divergence ( that lacks objective meaning) and it's exactly the relativity of this measure that implies that these systems when interacting in "their view of space" are subject to interactions from the disagreeing systems.

But this is all open questions as I see it, and the details remain to be nailed exactly. For any later comers, my modest contribution to this thread on TOE etc is just to try to convey my view what I think requiring a coherence of reasoning suggest about how it may or may not look like. And that this alone, may actually guide us to finding not a static TOE, but maybe as close to an effective TOE as might be possible.

/Fredrik

moniker2

Oct1-09, 10:57 PM

It was a trick: I did not want to discuss the meaning of "EXISTS", I wanted to show that there is no concensus on even basic things.
Let’s admit, based on this and all previous discussions: there is no consensus about the meaning of words:

Event
Exist
Real / Virtual
Reality/Realism
Measurement
Observation
Particle
Spacetime (4D? Bulk?)
Etc etc.

If we think about the words as some clouds in some space of meanings, then before they had sharp borders. Then they because more and more fuzzy. They started to intersect with each other.

But wait: this is exactly what Max Tegmark predicted! On our way to TOE all these words MUST lose their meaning, becoming “mere labels” (c) These fuzzy clouds are the last image we see as the objective of our science photo-camera is de-focused completely.

labels? I got kick out of the forum two years ago for posting this.

Liquid Space Theory
F = force
M = mass initial
V = velocity
C = speed of light
A = acceleration
H = Planck’s constant
E = energy

F = {[(m/ (1-(v^2/c^2)) ^(1/2)]-m}a

Second law of time

A ={{[(m/ (1-(v^2/c^2)) ^(1/2)]-m}^-1}f

Infinite change of time

M = [f /{[(1/ (1-(v^2/c^2)) ^(1/2)]-1}a

Mass as a vector in a 3- orthogonal space

V = c [- (ma/ma-f )^2 +1]^1/2

Velocity of time

C = [v / [- (ma/ma-f )^2 +1]^1/2

Speed of light as a function of mass

E = {[f /{[(1/ (1-(v^2/c^2)) ^(1/2)]-1}a}{[v / [- (ma/ma-f )^2 +1]^1/2 }^2

Time conservation law

Wave = {{[f /{[(1/ (1-(v^2/c^2)) ^(1/2)]-1}a}{[v / [- (ma/ma-f )^2 +1]^1/2 }^2 } / h

(e / h)

Wave length and energy of the force
Energy of the force = {{[(m/(1-(v^2/c^2)) ^(1/2)]-m}c^2}
Wave = {{[(m/ (1-(v^2/c^2)) ^(1/2)]-m}c^2} / h

Time has an avg. 10^18 – 10^23 Hz

Not a good source at all but intresting...
http://www.timetravelinstitute.com/ttiforum/showflat.php?Cat=&Board=time_travel&Number=47124&Forum=time_travel&Words=satown&Match=Entire%20Phrase&Searchpage=0&Limit=25&Old=allposts&Main=46807&Search=true#Post47124

John86

Oct2-09, 03:53 AM

Thanks for your reaction Fra,

But this inference proces is a purely informational relational proces as i understand it ! The subjective observer acts on i'ts enviroment and viceversa am i right. Then this will have certain fundamental consequences for measurements undertaken in science, because they then are purely subjective and belong more or less to the classical measurement outcomes taking place in our brains.

Fra

Oct2-09, 09:22 AM

But this inference proces is a purely informational relational proces as i understand it ! The subjective observer acts on i'ts enviroment and viceversa am i right. Then this will have certain fundamental consequences for measurements undertaken in science

If I read you right, I can roughly agree so far.

they then are purely subjective and belong more or less to the classical measurement outcomes taking place in our brains.

? I don't quite follow this parts, and how it relates to the ideas I describe?

My ideas are not directly related to models of the human brain. Observer also does not refer to a human.

Observer is a general physical system.
The inference system is physical inference system, not a biological brain. If you use brain as a metafor for inference system, then any physical system has this. But the word brain and humans brings in totally misguiding associations. I do not think in terms of humans or brains at all.

Maybe I missed your point here?

Edit: Maybe your reason for talking about hte brain, is because you consider human science? OK, then I agree. BUT there are complications, humans are far more complex than particles, and humans are not only constrained to their brain. Humans pretty much control an entire planet, and has learned howto exploit control and use it's environment as an extension of itself.

So the inference system of human science inference, is not just the biological brains, it's much more. We have techonology, computers, libraries etc that are a significant part of our "complexity". Not to mention gigantic laboratories they we have built be exploiting our acquired knowledge of our environment. This technology continously increase.

But in a sense that's no different than how I picture it on the microscale, and how complexity is gained by taking control of the enviroment.

But all this, is no "problem" as I see. It's just another illustration that science is a complicated by evolving thing. Our environment, in several ways connects our subjective brains, so the emergent consensus is not subjective.

/Fredrik

John86

Oct2-09, 09:37 AM

No sorry you are wright. This doesn't work very well in biological systems. I used the human brain merely as a metaphore.

But is this inference proces purely materialistic of nature ?.

Fra

Oct3-09, 02:51 AM

But is this inference proces purely materialistic of nature ?.

I am not sure what you mean, if you mean if it's materialistic - as opposed to say something spiritual or divine :) Then yes it's materialistic.

However, what does "materialistic" mean? Usually that means it's made of matter, but in the reconstruction I envision matter is also emergent and I reall don't see a firm starting platform, this is exactly why the evolution appears as the ratioanl solution.

There is also a difference between the observers own inference system, and inference systems existing in it's environment (other obserers, or particles etc): From the point of view of any given observer, the inference system of the environment is reflected in it's own emergent inference system.

I picture a mutual selective pressure where at a certain level of equilibirum, the inference systems reach a maximum of consistency, this corresponds to the case where all observers are in maximum agreement about the "laws of physics". But du to intrinsic limitations of complexity, there can never be perfect consistency - this "residual inconsistecy" - manifests as interactions between the observers that are described by the locallly objective laws.

I used the human brain merely as a metaphore.

Ok, then it's great question. But of course, the inference system of the environment, is always inherently uncertain as inferred from the instrinsic perspective of one observer.

So, in my view, the evolving laws means that, not only like QM where we have set laws, and a state of the system (wave function) which evolves, we have both a state of the system, AND a "state" of the inference systems (state of laws) but these laws are not predictable from the inside view, there are only expecations - which gives an arrow of change - and the only way to find out the real future is to act as per the expectations, and also face the feedback.

In a well equilibrated system, one expects a layers of effective objective laws ot have been stabilised, realtive to which we have a time evolution probably like what we have in the current standard model - thus the standard model and QM, corresponds to steady state of effectively stable laws. The residual mutual uncertaints that are irreducible cause interactions that are descried by effectivelt(not fundamentally) fixed laws.

This is exactly how human science also works, but we have not yet translated this logic to physical interactions. I am convinced there is more insight to collect there.

In the end, "material properties" are properties of inferred inference systems, I'm stills struggling but for sure there is a close link with inertial mass and complexity of the inference system. This will also PROBABLY be strongly related to gravitational mass since the inference systems ability to take control of the environment and thus INCREASE it's own complexity(mass) will increase with it's own starting complexity(mass). I see great potentials on howto develop this into something nice.

The phenomenology of interactions would be expected when we can find the steady states of the effective laws. In there we should also hopefilly find some things that are currently "parameters". The parameters are explain as the ones required for a steady state.

/Fredrik

tom.stoer

Oct3-09, 04:05 AM

But is this inference proces purely materialistic of nature ?.

That's a very good question to step in again. Usually we distinguish (in an ontological sense) between physical objects (like electrons, photons, ...) and the corresponding laws (quantum mechanics, quantum field theory like QED, ...).

As far as I understand the idea of the mathematical universe everything is simply an entity, element, ... of a (consistent) mathematical framework. Therefore the ontologoical difference between physical objects and laws of physics does no longer exist.

@Dmitry67: Am I right?

Now back to the context of evolving laws due to inference processes.

@Fra: is there an ontological difference between objects and laws? are the objects somehow "materialistic" whereas the laws are "super-materialistic", i.e. is there a different level of existence forthe laws? or does the difference between objects and laws no longer makes sense?

If there is no difference between objects and laws then there should be no difference between evolution of laws and interaction of particles.

Tom

Fra

Oct3-09, 04:24 AM

@Fra: is there an ontological difference between objects and laws? are the objects somehow "materialistic" whereas the laws are "super-materialistic", i.e. is there a different level of existence forthe laws? or does the difference between objects and laws no longer makes sense?

If there is no difference between objects and laws then there should be no difference between evolution of laws and interaction of particles.

Tom

Yes, there is no distinct principal difference! The difference is merely the stability and decidability. Laws are the most stable structures in this evolving view, and they correspond to different levels in a hiearchy.

This is the unification. Nothing escapes the inference framework. Not even the inference system itself. However inference has two extremes: deductive logic or deterministic predictions, or free evolution. I'm exploiting the range in between.

/Fredrk

Fra

Oct3-09, 04:40 AM

If there is no difference between objects and laws then there should be no difference between evolution of laws and interaction of particles.

In here is also IMO the key to understanding the difference between (as smolin also pointed out about the validity of the current logic of eternal law in subsystems).

The same interaction can appear either described by effective laws, seen from an outside observer controlling/monitoring the environment, or as unpredictable evolution (the inside view).

The key I think is to see that these two pictures are not in contradiction, they are two sides of the same coin and I think one key is the scaling of the complexity of the inference system - this is why from the point of a more massive infrence system, things that to a small inference system appear unpredictable are effectively predictable.

One can think of this also as a sort of deeper "renormalisation" picture. The distinguishable laws are dependent of the complexity. But the scale itself is not objective.

/Fredrik

Fra

Oct3-09, 11:45 AM

One can think of this also as a sort of deeper "renormalisation" picture. The distinguishable laws are dependent of the complexity. But the scale itself is not objective.

Clarification:

One key question in my approach is, How does the inference systems themselves change as we scale the complexity of the inference systems?

This is exactly the same question as to ask, how a physical systems perceives physical laws as the systems get lower and lower mass. Ie. what "laws of physics" does say a proton "see" or a quark "see" and thus act according to?

I think this is a key to the unification. Since the logic of the action of these microconstitutiens are I think constrained by the relative simplicity or low complexity of their inference system.

Gravity I picture here beeing related to the fact that the running of the "complexity scale" is actually related to the physical process of a system loosing or gaining mass (by controling or loosing control of it's environment)

So all interactions, including gravity, really does have a very logical connection here. With some stretch of imagination this is how I probably with some strong biaos of mine interpreted some of Frank Wilzceks ponderings about what symmetry really is.

One can also picture here a plausible way to expect something like asymptotic freedom as we scale down the complexity of the inference system (which is what happens inside the collisions in a high energy experiment), since some interactions themselves become less distinguishable from the inside poitn of view - thus their mutual interacting get weaker.

As far as I see, it's not hard at all to imagine how this inference reasoning connects to many open questions in physics. That's one of the motivators for me. It's really exicting and promising, and it has IMHO a very higg level of coherence in the reasoning, which is very important for me. But indeed it's also currently at least very fuzzy.

/Fredrik

tom.stoer

Oct4-09, 06:25 AM

Usually we distinguish (in an ontological sense) between physical objects (like electrons, photons, ...) and the corresponding laws (quantum mechanics, quantum field theory like QED, ...).

As I am not sure if everybody understands my reasoning correctly I would like to comment on this remark. Therefore I use a very simply, unrealistic example, namely a universe with only finitely many, structureless, massive bodies interacting via V(r) ~1/r. There are no humans (therefore no measurement, no minds/brains etc.).

1) you have the bodies
2) you have a representation of the bodies, their masses mi and coordinates ri; these representations are equivalent to the trajectories
3) you have the physicals laws; in my example there is just one law, namely an Hamiltonian H(ri, pi); m-dependence suppressed.
4) initial conditions for the movement of the bodies; these are not contained in 3)
5) in addition you can think about a sheet of paper on which you can write H, draw the trajectories etc.; This is certainly different from (2) and (3); I would say that physical laws "exist" even if there is no sheet of paper or computer monitor to display it.
6) you can introduce god into that theory; he may know about all bodies, laws, trajectories and initial conditions

Note that the existence of (3) is different from the existence of the bodies, simpy because (3) applies for all bodies you can think about, whereas (1) applies on to the bodies which exist in a physical sense. In a universe with three bodies you can still think about applying H to a fictitious fourth body.

As far as I understand the discussion here the aim is to collapse at (1) - (4) into one framework where the differences between them disappears or become irrelevant (just as the difference between the earth and the moon is irrelevant in the context of Newtonian physics; they are two special cases of massive bodies, nothing else). As this would be a ToE it would certainly contain (5) and (6) as well.

But I think this is where most people will have problems with. It is by no means clear that a physical body and its mathematical representation (in some appropriate framework) are identical! We haven't found such a framework; we cannot even guess how it would look like. I have tried to describe a very simple universe,but still most of iús would agree that the sentence

(Mmoon, Rmoon) IS the moon

is wrong. It is a representation of the moon.

I have one final question rearding MUH: We discuss very complex issues like universes with different physical laws. Let's discuss one rather simple problem, namely two universes looking absolutely identical, except for the fact that in one universe the solar system is missing. Are these too universes two different mathematical frameworks, or are they on such framework in two different occurences? Does the MUH imply that all those universes (w/ or w/o solar system; w/ or w/o you and me, with other planets) exist? Does the possibility that I am able to write some equations specifiying the movement of a 10th planet in our solar system create universes where this planet exists?

Dmitry67

Oct4-09, 07:41 AM

As far as I understand the idea of the mathematical universe everything is simply an entity, element, ... of a (consistent) mathematical framework. Therefore the ontologoical difference between physical objects and laws of physics does no longer exist.

@Dmitry67: Am I right?

correct

Dmitry67

Oct4-09, 07:44 AM

1) you have the bodies
2) you have a representation of the bodies, their masses mi and coordinates ri; these representations are equivalent to the trajectories
3) you have the physicals laws; in my example there is just one law, namely an Hamiltonian H(ri, pi); m-dependence suppressed.
4) initial conditions for the movement of the bodies; these are not contained in 3)
5) in addition you can think about a sheet of paper on which you can write H, draw the trajectories etc.; This is certainly different from (2) and (3); I would say that physical laws "exist" even if there is no sheet of paper or computer monitor to display it.
6) you can introduce god into that theory; he may know about all bodies, laws, trajectories and initial conditions

This is what Max Tegmark calls a 'baggage'. If you try to get rid of ALL words in this toy universe, you will see that the difference between 2 and 3 will dissapear. 1 is a mere label (definition of a 'body'). 5 does not make any sense. "I would say that physical laws "exist" even if there is no sheet of paper or computer monitor to display it." - correct.

But I guess the your idea to discuss some 'toy' universes is a very good one; we dont know OUR TOE, so it easier to discuss simpler universes. For example, "Game of Life" is a perfect example. So, in the Universe "Game of Life", what is a difference between structures (bodies) and laws? When I was young boy, I discovered that game and played a lot with figures on the chessboard. Does that game require a chessboard?

I think many people agree that methematics can perfectly describe the reality. But (they think) the formulas are dead until you "incarnate" them into something, untill you fill them with some substance. But for TOE, there should be no magical substances, because TOE by definition must describe everything.

TOE is different from any theories we had because TOE ends the reduction: "bodies-molecules-atoms-hardrons-quarks-strings.." so the most fundamental entities can not be "made of something". If they are not "made of something" they are just "described by formulas". I dont see any possible void where the difference between the ultimate description of reality and reality can hide.

Dmitry67

Oct4-09, 08:11 AM

I have one final question rearding MUH: We discuss very complex issues like universes with different physical laws. Let's discuss one rather simple problem, namely two universes looking absolutely identical, except for the fact that in one universe the solar system is missing. Are these too universes two different mathematical frameworks, or are they on such framework in two different occurences? Does the MUH imply that all those universes (w/ or w/o solar system; w/ or w/o you and me, with other planets) exist? Does the possibility that I am able to write some equations specifiying the movement of a 10th planet in our solar system create universes where this planet exists?

So, the laws are identical, but initial conditions are different?

If Universe is infinite, all combinations must happen. But MUH is much easier to be accepted if you accept MWI (eliminating the problem of initial conditions of matter in our universe) and if there is a mechanism to generate all possible Universes with all possible parameters of the Standard Model (eternal inflation?).

MUH will be in big trouble if MWI would be proven wrong or if there are some fundamental initial conditions (God Had choice when created our Universe). This is a good news because it is a falsifiable prediction.

Max Tegmark wrote:

common feature of much string theory related model building is that there is a “landscape” of
solutions, corresponding to spacetime configurations involving different dimensionality, different types of fundamental particles and different values for certain physical “constants” , some or all of which may vary across the landscape. Eternal inflation transforms such potentiality into reality, actually creating regions of space realizing each of these possibilities. However, each such region where inflation has ended is generically infinite
in size, potentially making it impossible for any inhabitants to travel to other regions where these apparent laws of physics are different. If the MUH is correct and
the Level IV multiverse of all mathematical structures (see Section V) exists, this historical trend is completed: even the “theory of everything” equations that physicists
are seeking are an environmental accident, telling us not something fundamental about reality, but instead which particular mathematical structure we happen to inhabit,
like a multiversal telephone number. In other words, this would entail a crushing complete
defeat of fundamental physical laws. However, contrary to how it may at first appear, it would not constitute a victory for initial conditions in the traditional sense.

There is nothing “initial” about specifying a mathematical structure. Whereas the traditional notion of initial conditions entails that our universe “started out” in some particular state, mathematical structures do not exist in an external space or time, are not created or destroyed, and in many cases also lack any internal structure resembling time. Instead, the MUH leaves no room for “initial conditions”, eliminating them altogether. This is because the mathematical structure is by definition a complete description of the physical world. In contrast, a TOE saying that our universe just “started out” or “was created” in some unspecified state constitutes an incomplete description, thus violating both the MUH and the
ERH.

Fra

Oct4-09, 11:51 AM

As I am not sure if everybody understands my reasoning correctly I would like to comment on this remark.

If you were referring to me then I defeinitely think I see your position. It's just that I don't share it so to speak. My arguments serve to try to convey why your position is questionable from my point of view, and what the weaknessess are. But it doesn't mean I don't see your position.

But indeed, I also see what the weaknesses of my view are - from your point of view.

Somehow I think this mutual understanding is as far as we can get until you agree to join the dark side ;-)

I feel I have tried the structural realist side. It was the side I am coming from and my own reasoning and experience has lead my onto another path because the realist/axiomatic view has IMO serioust problems, some of that I think you posted about as well, and it's not cast in stone but it would take extraordinary arguments or input the revise this position.

6) you can introduce god into that theory; he may know about all bodies, laws, trajectories and initial conditions

This is one of the things I objected to before. The birds view supposedly justifies the realism. But as long as the complete birds view is inaccessible, which it is for several reasons it seems to be only a mental construct to justify a (from my point of view) "flawed" reasoning.

But I think you know my position there already no need to repeat.

But I think this is where most people will have problems with. It is by no means clear that a physical body and its mathematical representation (in some appropriate framework) are identical! We haven't found such a framework; we cannot even guess how it would look like.

Maybe I mix up your comments on the evolving law idea, and Dmitrys view, so I am not sure to whom this was addressed.

If the comment applies to my view, then it's true that many has problems with it. It's like having the ground under you removed. But that we cannot even guess is not fair I think. I think the latest discussions has hinted at least conceptually how the framwork could look like. At least to speak for myself, I have a much better guess even if it's currently immature how this evolving framework is going to solve problems, than ideas howto make progress starting from the QFT framework and GR without changing anything.

The most common and most natural objection to the somewhat inference approach is I think that it renders everything apparently subjective, and that it would be hard to do science without an objective basis. I've tried to explain how this is not a problem once you see the whole picture.

But as far as I know, compare to string theory and the other large competing approaches, it seems that almost nooone is working seriously on this. Wether it's because noone has any ides or simply because the ideas are suppressed by the community is another discussion.

So I certainly have ideas on this framework, and I will also keeping searching for it independently of wether most others aren't motivated. The price I pay is of course, that I am on my own, an this is constrained to beeing a sidetrack along with alternative professional carriers. But I think that is a reasonable price ot pay. It would not make sense for the public to invest in all small possibilities. That some minor approaches are suppressed is somehow how the world works.

New ideas doesn't necessarily come out of the mainstream work. So the fact that there aren't much "almost mainstream" ideas on how this framework is like is not one bit discouraging or surprising for me.

/Fredrik

Dmitry67

Oct4-09, 12:01 PM

Fra, it was difficult for me to formulate the question about your approach, because everything looked so fuzzy. But now I have one:

So, everything is subjective. Say, there are observers O1, O2, ON, ... etc

Is view of different observes consistent? Or is the notion of self-consistency applicable? If yes, then to what extent? For example, in the macroscopic realism approach all views are consistent on the macroscopic level. But in MWI, view of observers in different branches is not macroscopically consistent (in different branches, but consistent in the same branch). Is it possible that O1 is observing the dead cat, O2 - alive cat, and O3 denies the existence of observers O1 and O2? Are there any invariants in your approach?

tom.stoer

Oct4-09, 01:05 PM

@Fra: I am sorry for the confusion. I did NOT address you, neither with the comment that not everybody is clear about the problems, nor with the problems people have about the approaxches just discussed.

Why I was posting this was mainly because I found one aspect which seems to be common to both, Fra and Dmitry67, namely the fact that the differences between objects, representation of objects and laws for the objects fades away. In that sense both approaches are even more radical than evolving law, multiverses etc. Therefore I think that even people who could basically agree would refuse to agree to the more radical implications.

Fra

Oct4-09, 03:48 PM

Dmitry, we concluded previously that we differ quite a bit, so my response to the below questions are relative to my reasoning.

Is view of different observes consistent?

Note that an "inconsistency" requires an inference system, and in the deductive inference inconsistency usually means you can make two deductions which shows a contradiction, say something beeing both true and false at the same time. Such inference system is "inconsistent".

But in my view, the inference system itsel is evoling, and always uncertain! An inconsistency of the type above in this case, simply is an "observation" that decreases the confidence in the inference system in question, which effectively is why it evolves.

Is view of different observes consistent?

Also for this to even have meaning in my view, the observers must be interacting.

In this respect I think Rovelli phrased it well in his RQM paper that the only way for two observers to relate their measurements is to communicate - ie. to interact.

So given that requirement, then a certain form of consistency or consensus between the observer is emergent, as a result of the interaction.

This means that in my view

- observers that aren't interacting, does not even have the notion of mutual consistency defined since it is only defined throught the interaction.

- even observers that are communicating, can be inconsistent transiently, but mutual inconsistency always means off-equilibrium and thus interaction forces.

The main difference from the standard notion of consistency as defined by say a symmetry transformation, is that in my view this transformation itself is not given, it's emergent, and without interactions the transformation itself is undefined.

But in MWI, view of observers in different branches is not macroscopically consistent (in different branches, but consistent in the same branch).

I'm not much into MWI, but certainly if the observers are in different non-interacting branches the notion of consistency has no meaning; which also means that any INconsistency is IMO simply unphysical because hte physical event realising the "inconsistency" will never happen.

Is it possible that O1 is observing the dead cat, O2 - alive cat, and O3 denies the existence of observers O1 and O2? Are there any invariants in your approach?

Sure, that's possible. but wether it's a stable state or likely to be observered is another question :)

In my view, it's not so much a question of what's possible, but more of what's probable to
be observed. In general inconsistencies means interaction forces, which means off-equilibrium.

Are there any invariants in your approach?

There are subjectively EXPECTED invariants, that is reflected in the action of the observer. But these invariants are not universal, global or objective and are generall subject to evolution as real interactions take place.

/Fredrik

friend

Oct4-09, 07:02 PM

Note that an "inconsistency" requires an inference system, and in the deductive inference inconsistency usually means you can make two deductions which shows a contradiction, say something beeing both true and false at the same time. Such inference system is "inconsistent".

But in my view, the inference system itsel is evoling, and always uncertain! An inconsistency of the type above in this case, simply is an "observation" that decreases the confidence in the inference system in question, which effectively is why it evolves.

In this respect I think Rovelli phrased it well in his RQM paper that the only way for two observers to relate their measurements is to communicate - ie. to interact.

So given that requirement, then a certain form of consistency or consensus between the observer is emergent, as a result of the interaction. /Fredrik

Fredrik, your "theory" or "view" seems to lack any faith in reason or logic. And I see an inconsistency in what reasoning you so far present.

What you are suggesting is that there is no system of logic applicable to all of reality independent of observation. But isn't that what we are forced to assume, unless we are to think there is something in reality that is inherently illogical. That doesn't sound like a very plausible scientific premise to build any kind of theory on. I think the scientific expectation that all things are reasonable means we have to start with the assumption that all things are logically consistent with each other. The only question after that is how does that dictate the math we are to use.

Can consistency "emerge" from an illogical basis? That seems to be what you are saying. But I think that is impossible. Consistency can only be derived from a logical system - and not from a system of contradictions. If different Observers see everything to be logical arbitrarily close or distant from each other, then the entire universe must be everywhere and always a consistent set of facts.

If you think your theory somewhere can have inconsistencies in it, then your theory is so vague and speculative that it would be impossible to write any mathematics to describe it. I think you need to come to your senses and appologize for your incomprehensible musings.

qsa

Oct4-09, 07:39 PM

friend, do you think this website can support DR Max Tegmark's theory

http://www.qsa.netne.net

friend

Oct4-09, 08:22 PM

friend, do you think this website can support DR Max Tegmark's theory

http://www.qsa.netne.net

Obviously we have no choice but to describe reality with mathematics; there is no other language capable of describing it. But there are things in reality that have properties that are discovered through experiment, mass and charge of an electron, for example. These "inherent" properties are the 30 or so constants inserted by hand into the Standard Model. However, it is hoped that eventually we will find some mathematical explanation for these inherent properties, and so they too will be derived mathematically from some more basic theory. So ultimately I think all of reality can be derived from a pure mathematical/logical basis. We just haven't found that basis yet.

Everything having a mathematical basis does not mean that every mathematical system describes reality. It might describe a subset of what we know because it may serve as an approximation in some limited realm. For example, the system of whole numbers can be used to count apples in a basket. But that does not mean that reality is limited by this narrow subset of mathematics.

So the question is what mathematics can we trust will lead to a theory of everything. I suppose we will not be sure until it reproduces something familiar to physicists, like the basic formulation of QM or GR.

Fra

Oct5-09, 12:47 AM

Friend, I certainly respect your position that you don't see any possible way howto make sense of of the reasoning I advocate.

There is a certainly a clear kind of logic in my approach, but it seems you do not see it, or you see it as inconistent, that's because I don't believe in rigid axiomatic deductive inference - that systems seems not flexible enough to efficiently describe nature.

I guess we will see in the future if we are able to overcome all problems and solve all open problems in physics without radically finding a more flexible framework.

What you are suggesting is that there is no system of logic applicable to all of reality independent of observation. But isn't that what we are forced to assume, unless we are to think there is something in reality that is inherently illogical.

Let's just note for a fact, that the logic system we are all talking about here ARE in fact inferred from interactions - human laboratory interactions with nature. Even mathematics and logic are produced by humans as a result of contemplation and study of nature.

So what I am suggesting is not really as insane as it may first seem, if you see it in the right way.

Maybe you you then say that earth and nature and the laws of nature was here long before humans - yes of course it was, but at a lower level even matter was once not here, instead it was maybe emergent from a great chaos?

I think the scientific expectation that all things are reasonable means we have to start with the assumption that all things are logically consistent with each other. The only question after that is how does that dictate the math we are to use.

What I suggest is not all that different to what you say. The difference is wether the logic system is fixed and eternal, or if it's emergent?

At human level for example, are we creating the laws of physics or are we discovering them?

I'm saying there is no clear difference.

Can consistency "emerge" from an illogical basis? That seems to be what you are saying. But I think that is impossible. Consistency can only be derived from a logical system - and not from a system of contradictions.

I think I have tried to explain all this already, but I'm sorry to not be able to be more clear but this isn't easy stuff. And there are for sure many unsolved problem as well.

But the problem even in Your approach, from a scientific point of view is, when a given "logic system" or say "theory" is proving WRONG, it when it's falsified - HOW do you find a new theory without starting from scratch? - This is where my main point is, here my view contains a rational scheme for howto infere the new inference system from the old system given detection of slight inconsistency.

This even develops the scientific method in the area where popper left a whole - the logic of hypothesis generation? Hypothesis TESTING is the easyl part.

If you think your theory somewhere can have inconsistencies in it, then your theory is so vague and speculative that it would be impossible to write any mathematics to describe it. I think you need to come to your senses and appologize for your incomprehensible musings.

I don't see what I need to apologize for, except that I am sorry that I don't have more progress made. I rather see adding my point of view in here as part of an intellectual discussion in the search for the framework what can solve the real problems in physics.

As I said before, the real argument is when solution on open problems are on the table. Until them I have to admit I find the competing arguemtns far more inconsistent, simply consistency doesn't lead to uniqeuness. The evolving logic system solves to a larger extent the question of "why these laws".

/Fredrik

Dmitry67

Oct5-09, 02:46 AM

Fra, do all observers share the same verson of mathematics? Is it possible that for some observers 2+2=5?

qsa

Oct5-09, 03:21 AM

Dmitry, do you think this website can support DR Max Tegmark's theory

http://www.qsa.netne.net

I hope you got the private message I sent you

Fra

Oct5-09, 03:54 AM

Fra, do all observers share the same verson of mathematics? Is it possible that for some observers 2+2=5?

I am not sure what you mean here, you probably need to provide an example so I can interpret this.

A fundamental thing in my view is that in a certain sense all observers share what I call a natural or rational action. There is a way of "counting evidence", and from each inside view this framework is in a certain same the same. The reason for this expectation is that any observer not implementing a rational action (the meaning of this is a different discussion so I'll leave that) will be exposed to forces that selects for a particular change.

My view would contain a reconstruction of a kind a new probabilistic framework, where the "probability" rather than frequentists intrepretation is a sort of "inside count" of evidence. Then from such a picture, there is a "natural action" which is closely relate to the principle of minimum information divergence, also related to max ent principles and principle of least action.

I'm basically looking for a deeper way to infere a transition amplitude a la path intergral, where the action itself is defined through a recursive flow. So the action S is not hardcoded, it's itself evolving.

In there, my basic conjecture is that there is a rational and natural way to count evidence, and the so constructed "information state" contains a natural action! No need to postulate wicked string actions, the action is a natural action in the inference system.

This of statistical mechanics, where the microstructure defines a natural measure of missing information (entropy). Now picture this idea much more genralised, where the microstructure is not a baggage but rather is a result of evolution, and also the microstructure is more complex, like a system of related structures, defined by transformations, like a complex memory system. Then such a complex microstructure-system implies a much more complex "natural action" also for changes. This is what I'm trying to work out.

A space of differential changs are defined, and on that space a natural information divergence measure is defined. That defines a transition amplitued for each possibility. But as the microstructure is not one simple space, but an evolved system of spaces, and the microstructure is not based on continous probabilit but on "counting evidence" (basically a combinatorical approach) interesting new logic emerges. Quantum logic superposition are expected gets natural explanation here. quantum logic is simlpy (at times) more FIT than classical logic.

When I have worked this out, I will produce some papers for sure. Until then I constrain my reasoning here to general IMO sound arguments.

When I get to the point of publishing someting concrete one can talk about "theory", and it will be more readily subject to critics. To me it's simple, either this will produce new insights or it will not. If not, it's a failure.

/Fredrik

Dmitry67

Oct5-09, 04:28 AM

But what value your "theory" might have if we dont agree that all observers share the same logic? Then your theory can be valid for observer Fra but not be me

Fra

Oct5-09, 05:04 AM

But what value your "theory" might have if we dont agree that all observers share the same logic? Then your theory can be valid for observer Fra but not be me

Of course, the theory will be the same for me and you, and all scientists on earth. This is explained by the emergent objectivity. The basis for our expectations are massive enough, and we are well equilibrated enough to be exactly in consistenct _for all practical purposes_.

I never said that everything is totally subjective in an uncontrolled way, that would make little sense. This makes sense only if complemented with a mechanism for emergent objectivity. This emergence, is a physical process, but if we are talking about the laws of subatomic physics for example, not doubt all of us will be in agreement.

The supposed value of this approach, is that it will explain the choice of the emergent physical laws. In particular interesting is this to me when you consider the case where the observers are not you and me, bu say a proton an a neutron for example. I think this scheme will constrain the possible mutual actions of these systems.

The predictive power here, is that the insight of the "inside perspecitve" will allow us humans from an external perspecitve defined by a laboratory frame to constrain how the actions of microphysics is like, what symmetries we have etc. So this should eventually (when it's mature) give clear predictions.

The idea is to use the zero end of the complexity scale, to constrain the possible actions. And then see what happens as the complexity scale grows. This complexity scaling is also given a physical interpretation as generation of mass.

This is why the laws of physics emerge along with massive observers(matter).

Sure, maybe I will fail in this vision, but that's my loss, I'm not eating anyones elses investments :) Unfortunately the same can not be said about some other approaches.

/Fredrik

ConradDJ

Oct5-09, 06:57 AM

I think many people agree that mathematics can perfectly describe the reality. But (they think) the formulas are dead until you "incarnate" them into something, until you fill them with some substance. But for TOE, there should be no magical substances, because TOE by definition must describe everything.

TOE is different from any theories we had because TOE ends the reduction: "bodies-molecules-atoms-hadrons-quarks-strings.." so the most fundamental entities can not be "made of something". If they are not "made of something" they are just "described by formulas". I dont see any possible void where the difference between the ultimate description of reality and reality can hide.

Hi Dmitry --

The difference between a “reality” and a “description” of that reality is that a reality is assumed to exist and to be well-defined “in itself”, while a description requires a context in which what is described has meaning, in some sense – i.e. makes a definable difference to something else.

To me, the fundamental point of both Relativity and QM is that we don’t have a base-level “reality” that’s well-defined in itself, without requiring any frame of reference or any context of interaction to define it. What’s physical about the physical world is not that it’s “made of something”, but that it’s observable – that it provides reference-frames and interaction-contexts that make everything in it physically meaningful.

Of course both Relativity and QM are mathematical theories. And in both cases, we can certainly ignore the questions about what makes things observable and why observing something makes a difference to the ways in which its description is determinate.

If we look only at the mathematics, lo and behold, everything looks well-defined – because it’s easy for us to convince ourselves that logic and mathematical structures “exist” in some absolute sense. We live in a physical environment that gives us lots of distinct identifiable objects, so counting makes sense, “A=A” makes sense. The physical world has a very clear and simple geometry, so the concept of a point or an interval or a vector makes sense. Even something as paradoxical as a “continuum” of points makes intuitive sense to us, because of the way our world is physically structured. We can hardly imagine a world in which these ideas don’t make sense.

However, we’ve learned that in the early stages of our universe, the physical conditions did not exist that would make any of these basic concepts meaningful. We tend to assume that this doesn’t matter – that the basic structure of the world will turn out to be well-defined mathematically, and that the mathematical structure is all physics cares about anyway.

That’s a reasonable point of view, but not necessarily correct. The other point of view is that the context of relationships that lets things be defined and observed, that let them make a definite difference to each other, is important and can’t be neglected. As Fredrik says, this is not necessarily “subjective” – we’re not talking about “conscious” observers. We’re talking about the aspects of physical structure that provide a context of meaningful definition for other aspects of physical structure.

Ultimately, as you know, mathematics is based on undefined elements – points and lines, for example – and logical operations like “=”, also undefined except for their formal properties. Physics is different – everything in physics has physical meaning because there’s a context of other physically observable regularities to which it can make an observable difference.

Even if each of these regularities is describable mathematically – and I assume that’s the case – the functionality of such a system of mutually-defining types of structure is something entirely different from the formal self-consistency of a mathematical system.

I don’t think Tegmark’s point of view has any real merit – except that it demonstrates the difficulty we have in conceptualizing the difference between “physical” and “mathematical” -- as obvious that difference is to us in ordinary life. The world he describes is the world of all possible mathematical structures... and so? By claiming this is the physical world, all he’s doing is making explicit the common assumption that we can safely ignore the aspects of physical structure that make things observable.

ConradDJ

Oct5-09, 07:16 AM

Also for this [consistency] to even have meaning in my view, the observers must be interacting.

In this respect I think Rovelli phrased it well in his RQM paper that the only way for two observers to relate their measurements is to communicate - ie. to interact.

So given that requirement, then a certain form of consistency or consensus between the observer is emergent, as a result of the interaction.

This means that in my view

- observers that aren't interacting, does not even have the notion of mutual consistency defined since it is only defined through the interaction.

- even observers that are communicating, can be inconsistent transiently, but mutual inconsistency always means off-equilibrium and thus interaction forces.

The main difference from the standard notion of consistency as defined by say a symmetry transformation, is that in my view this transformation itself is not given, it's emergent, and without interactions the transformation itself is undefined.

I'm not much into MWI, but certainly if the observers are in different non-interacting branches the notion of consistency has no meaning...

Fredrik – I just want to underline this point, with which I completely agree.

Rovelli points to this “emergent” agreement among observers as what’s most remarkable about the structure of the world as described by QM. But as I’ve said before, he doesn’t go further to tell us what’s involved here – what the structures are that make this work.

I think you’re right that there’s a parallel between what scientists do in observing things and developing a coherent picture of the world, and what happens in the world itself at a basic level. What’s “physical” about our world, I argued in the post above, is precisely that it develops a coherent “picture” of itself through physical communications among all its participants.

It seems reasonable to me that your quest for an internal inference-logic would play a role here – just because the “picture” intercommunicated among things is not precisely well-focused to begin with, being limited by the discrete quantum nature of interaction.

But it seems to me the most basic issue has to do with the existence of observation-contexts (“measurement situations”) in which any information at all can be conveyed – since without some sort of primitive information-exchange, inference has no data to work with.

Dmitry67

Oct5-09, 07:21 AM

Ultimately, as you know, mathematics is based on undefined elements – points and lines, for example – and logical operations like “=”, also undefined except for their formal properties. Physics is different – everything in physics has physical meaning because there’s a context of other physically observable regularities to which it can make an observable difference.

Mathematical entities are abstract. They are not reducted to the simpler entities; but it is wrong to say that they are undefined! They are defined using the relationships between them.

This is exactly what we expect from TOE. If some theory would say that time consists of timions, and strings constist of vibrions, then by definition it would not be TOE - it would be just a another step towards the understanding the structure vibrions and timions.

In TOE the ultimate entities MUST (it is not a justified hope - there is just no alternatives) be abstract, defined (exactly like in mathematics) based on the relationship with them.

ConradDJ

Oct5-09, 08:25 AM

Mathematical entities are abstract. They are not reducted to the simpler entities; but it is wrong to say that they are undefined! They are defined using the relationships between them...

In TOE the ultimate entities MUST (it is not a justified hope - there is just no alternatives) be abstract, defined (exactly like in mathematics) based on the relationship with them.

I get your first point... my old geometry teacher gave us points and lines as undefined elements, but it probably does make more sense to think of them as inter-defined, in terms of each other. However what makes them "abstract" is that there is no requirement that anything actually be observed by anything else -- i.e. that any information about anything be communicated. We are happy to stay in the realm of abstract definitions, where an interaction is just an instance of an equation -- nothing actually "happens" and no information is exchanged.

In a mathematical system, what counts as a "point of view"? Surely it's true that in the physical world that there are points of view, and information in fact gets exchanged between them. To quote Rovelli, "Physics is about the descriptions systems give of other physical systems."

So my point is just that the kind of inter-definition you're talking about is something quite different from the mutually-defining observation-contexts that we know exist in the physical world. You don't have to be in a mathematical system to "see" it -- in fact there's no meaning to being in it, and the "seeing" is a purely mental activity.

This is not to say that observation-contexts may not someday be modeled in some sort of mathematical system. But envisioning them abstractly, "from the outside", will still be something purely mental, derived from an actual experience of physically being-there, participating with things.

Again, I don't mean to deny the rationality of a viewpoint that says -- whether things are observable has nothing to do with the basic physics. But QM has clearly called this into question, at least. So it's also reasonable to try to understand physical observation-contexts and how they differ from mathematical contexts of definition.

Dmitry67

Oct5-09, 08:52 AM

ConradDJ, so what you are saying is that mathematical structure is different from reality, because it is 'dead'. In order for any mathematical structure to become reality, there must be some magic process used, a process, which 'incarnates' the formulas into reality (or how hawking called it "breathing fire into formulas"). I just wanted to confirm that my version of your vision is correct before I answer.

qsa

Oct5-09, 09:49 AM

ConardDJ, I don't know what Dmitry has in store for you, but you can look at it this way. We can write this equation x^2+y^2=r^2 and then draw a circle that represents it, wow! We have already breathed life into our equation. Now complicate your equation and as its solution complicated structure resembling particles interacting gravity doing its job and you start plotting them. as your model is so sophisticated (a 22nd century physics) early life begins to appear...and so on. When you look at your 3D computer screen(probably made by sony-just trying to be funny-!) you see people are doing their thing( not unlike how nurbs mathematics generate one hell of a realistic scene. Do they feel alive and real? You bet. for us are in a computer or we exist because of the imperativeness of the existence of math, that is a secondary question and I think with our power of science at that time the question should answered relatively easy.

friend

Oct5-09, 11:39 AM

What I suggest is not all that different to what you say. The difference is wether the logic system is fixed and eternal, or if it's emergent?

But the problem even in Your approach, from a scientific point of view is, when a given "logic system" or say "theory" is proving WRONG, it when it's falsified - HOW do you find a new theory without starting from scratch? - This is where my main point is, here my view contains a rational scheme for howto infere the new inference system from the old system given detection of slight inconsistency.

Fredrik

dude, either something exists or it does not. For what observer is that ever going to change? If things exist, then you can count them. For what observer is that ever going to change?

The trouble here is that abstractly, we can consider the possibility that something does not exist. Our logic has both true and false values. But in reality there is no state of non-existence. There is no physical entity that does not exist. What we are left with is a logical conjunction of all the little pieces that do exist. If any one of them did not exist, then that would make the whole thing a false description.

The question is how do you manipulate a conjunction of propositions you can count into mathematical formulas that describe physics? Every mathematical formula asserts that given some input a particular outcome results. And this is exactly what the logical operation of "material implication" does, if a premise is true (or given) then a conclusion results. So the trick is to somehow represent a conjunction in terms of implication and to describe implication in mathematical terms to see if you get something that looks like physics.

I've seen this done. But it is not on the arXiv yet. If you want to see the math, just PM me.

Dmitry67

Oct5-09, 12:42 PM

Rereading your post...

Ultimately, as you know, mathematics is based on undefined elements – points and lines, for example – and logical operations like “=”, also undefined except for their formal properties. Physics is different – everything in physics has physical meaning because there’s a context of other physically observable regularities to which it can make an observable difference.

So, physical structures are different from the purely mathematical ones, because they are physical? :)

So my question, as you could probably quess, how you can tell a physical system from a purely mathematical one? (this question is not so easy as it sounds)

qsa

Oct5-09, 03:04 PM

When a complex molecule is simulated on a computer with mathematical modeling, you can see how it vibrates and responds to environment, it looks alive. The algorithms that produced those molecules (however crude) are mathematical containing line, points, vectors, surfaces, probabilities, you name it. What we conjecture, that by a similar process we the “physical” become alive because of computation. The only difference is we can see the simulation of ourselves by ourselves without a computer screen. And this simulation is real because math is the only thing that is real = fact, what else could be? It will always exist regardless. Everything else is considered to be subjective by definition because of not being “scientific”. In another word, I can tell you what math is but can you tell me what physical is really, hay, and don’t explain it using mathematics ok, I’ll be really mad!

qsa

Oct5-09, 03:05 PM

Fra

Oct5-09, 03:18 PM

I think I've tried to convey and motivate the ideas behind evolving INDUCTIVE inference system and law, as constrast to fixed, external realist type of DEDUCTIVE inference. There is no point for me in repeating more or less the same arguments over and over again. If what I already said doesn't make sense, I'm afraid just echoing it again probably wont help, so I'll try to fade out my voice of this discussion for now at least :)

/Fredrik

Blackforest

Oct5-09, 06:10 PM

A very interesting discussion indeed : what is the physical reality of a mathematical object? And what is its ability to represent the reality? The strange point here is that any mathematical tool or object has at least one real representation : ink on the paper. And why should mathematical tools not also have a 3D representation? (e. g. the cubes of my theory).
Other point since the discussion here seems to be very general: do we really know what a mass is? It is usualy unserstood as a synonym of energy. But do we know what energy is? I mean we do not really progress in labeling things of which we in fact ignore the signification. I mean we have to propose a personal and courageaus representation of the nature if we want to progress. E. g.: Could it be that a mass is not describing the property of an object but is in reality just a natural tool to avoid discontinuity of the topologic background of our universe? a kind of propagating surgery kit? Who knows?
Best regards.

tom.stoer

Oct5-09, 06:13 PM

So, the laws are identical, but initial conditions are different? If Universe is infinite, all combinations must happen. ...
Hi, I stepped out for a while, but I would like to come back now.

My question was if I can create a universe with a tenth planet simply by writing down the general equations for the solar system and introducing a tenth planet in theory. You replied that this is a problem regarding initial conditions in an (infinite) universe.

Let's assume that within the MU you have several mathematical structures describing more or less our universe. As far as I understand you the different universes with - say - nine or ten planets - would belong to the SAME mathematical mutliverse but would live in different "areas" of the "many world" multiverse. If string theory is rigth then all its solutions would still belong to the same mathematical universe but live in different branches of the "many world" multiverse. But If I introduce another system like "game of life", then I would have to refer to the mathematical multiverse (I guess game of life is not a vacuum of string theory :-)

Looking at the "game of life" it serves as a toy model. It can either be described by a (completely Goedelized) mathematical structure and it would therefore be an own universe. Or it can be simulated by computer programs within our universe, therefore it can be seen as a substructure of the mathematical structure being our universe. Therefore within MUH we have the situation that mathematical structures can be own universes, or they can be substructures of universes.

Now we can look at the "game of live" from a third perspective. It can serve as a model for a universal Turing machine. Now having said that we remember that a universal Turing machine is able to simulate all other Turing machines. Therfeore game of life is able to simulate a large class of universes.

That means that a universe can exist on its own or it can be simulated by another universe. Within the universe everything looks identical (the structure is the same), but from the outside it looks different. Whereas the abstract structure can exit w/o any context, the simulated structure lives in a certain context. That means that we can construct an infinite tower of universes containing (simulating) each other.

But as any mathematical framework shall be free of any baggage, we must identify all structures with a certain kind of "algebraic isomorphism". So we must identify the Turing machine universe with the "game of life" universe.

Now let's assume for a moment that our universe is computable. Then we could (must!) identify it with a certain Turing machine or with a universal Turing machine + certain input. But then you have to explain why our universe looks so different from a Turing machine - or "game of life"! Of course I can easily escape this reasoning by giving up the idea that our universe is computable. So the other conclusion would be that our universe is not computable. Having concluded that our universe is not computable we immediately know that our universe is either (Goedel-)incomplete or inconsistent. As our universe exists and should therefore be consistent it must be incomplete. That means there are true statements which cannot be proven within our universe.

Now what does it mean for a mathematical structure to exists? Do we need a proof? What are these structures that exist within our universe w/o having the ability to be justified by our universe?

Blackforest

Oct5-09, 06:25 PM

Hi, I stepped out for a while, but I would like to come back now.

Now what does it mean for a mathematical structure to exists? Do we need a proof? What are these structures that exist within our universe w/o having the ability to be justified by our universe?

Let us assume that our universe exists (only because we can state it) and that it is a computer then there are some mathematical motors or structures existing to give it its internal coherence even if it is not complete (of course it is in creation) ! A self evoluting machine...

ConradDJ

Oct5-09, 07:50 PM

So my question, as you could probably guess, how you can tell a physical system from a purely mathematical one? (this question is not so easy as it sounds)

Dmitry, you are right on the money with this parenthetical remark. I think there is a fundamental – and very obvious – difference between physical systems and mathematical ones... but it is not at all easy to be clear about this difference. When I say obvious – well look, you can bang into something physical, but not something mathematical. That would presumably convince anyone but a physicist!...

But I don’t expect it to get anywhere with you or qsa, who understand physics (including banging into things) to be mathematical. If I understand you, you would say the above-mentioned difference is between mathematics that’s in your mind or in a textbook, and mathematics that really exists “out there” in Platonic eternality – one small part of which is what we experience as our physical world.

So how do we tell if the world around us is “just mathematics” or something more – and in what sense could it be “more”?

If we assume the physical world is a set of given, well-defined facts, I would say you are essentially right – or at least, right enough that there’s no point in arguing about it. Some of the facts would fall into mathematical patterns; others might just be random data, that can be located / defined in a mathematical framework. In that case I’d be happy to assume that someday we’ll have appropriate mathematics to describe all the facts... and if you want to say the facts are mathematics, fine... we’re down to semantics. In any case we would have something like a one-to-one mapping between the physical and its mathematics.

So is the physical world more than a set of describable facts? Yes – for one thing, it ’s a system that does its own describing. It’s a network of data-channels that communicates information about every part of itself to other parts. And a set of contexts that make incoming data meaningful for setting up other contexts.

There is a spacetime structure to this network, such that at any given point, information about certain other parts of the world (past light-cone) is accessible, while information about other parts is not. And there is an interactional structure such that in any given situation, certain information is measurable, while other information is not. And at any given point, the accessible / measurable information sets up a structure of possibilities (wave-function), out of which certain new information becomes “fact”, that gets communicated out as part of the base-information for other situations that create other facts.

So maybe your metaphor of “dead” mathematics and “living” physics is apt, in a certain way – though there’s nothing “magic” in this picture, this is just well-established physics. But it looks like physics is doing something that we don’t expect mathematics to do.

What we expect mathematics to do is give us coherent, more or less consistent descriptions of given structure. If we assume physics is just “a given structure”, then it’s not essentially different from mathematics. But we don’t expect a mathematical structure to create partial descriptions of itself and send them to other parts as a basis for new partial descriptions, or create measurement-contexts in which new information can be defined.

As I said above, I’m happy to stipulate that each component in this physical system will someday have a good mathematical description. My point is that there’s a functionality involved in how these components work together that amounts to “being physically real” – and that goes beyond what we think of as mathematical structure. But I admit that this functionality is very difficult to be clear about. And if anyone wants to take this as a sign that the whole idea is nonsense, I can’t very well blame them!

But here’s my question for you – if you take the physical world to be mathematical, then what in this mathematical system corresponds to a measurement? Or to the communication of information? In what way does this system provide descriptions of itself, and in what way are these descriptions made accessible only to certain parts of the system and not others?

In other words, can you really describe a mathematical system that looks anything like the world we live in, and does the kinds of things we see happening all the time? Or is it just a matter of faith that physics “must be” a mathematical structure “and nothing more,” based on our success in modeling many separate aspects of the world in equations?

Dmitry67

Oct6-09, 12:29 AM

ConradDJ, that you for your detailed answer, even I did not understand it completely. You claim that physics is something more, then mathematics, but you fail naming that mystical "more", admitting that it is "very difficult to be clear about"

Can we agree on a simpler statements:

1. If there is a difference between mathematical and physical, that difference can't be tested experimantally by the frogs inside the universe.

2. If universe is perfectly emulated, then frogs can't detect if it is real or perfectly emulated

3. Perfectly emulated system is isomorfic to a real one.

4. Hence it is absolutely irrelevant if we are emulated or not. In fact, the emulation is an argument for MUH: if there are universes which can emulate others, then all sorts of universes MUST exist

If we agree the theory of natural numbers is the same no matter if it is written by ink, or in PDF, or scratched on a stone, so mathematics is independent from the substance, then we must agree that it is irrelevant if it is emulated or not.

(Q: ha, but what if emulator glitches or I destroy the Turung Machine?
A: We are talking about the PERFECT emulation. If you cant atop it it is not)

This is also an answer to tom.stoer (1,2,3,4)

Dmitry67

Oct6-09, 12:35 AM

1 But here’s my question for you – if you take the physical world to be mathematical, then what in this mathematical system corresponds to a measurement? Or to the communication of information? In what way does this system provide descriptions of itself, and in what way are these descriptions made accessible only to certain parts of the system and not others?

2 In other words, can you really describe a mathematical system that looks anything like the world we live in, and does the kinds of things we see happening all the time? Or is it just a matter of faith that physics “must be” a mathematical structure “and nothing more,” based on our success in modeling many separate aspects of the world in equations?

1 Measurement is described by the physical laws of the Universe. As I said before, for the frogs inside Universe is real and measurable. It is like in MWI, narrow-minded observer in every branch would cry "only my branch is real!". The same in MUH - for any forg only "his" Universe is real.

2 You are asking for the ultimate TOE equations? Just a minute... where did I put them? ok, let me find a piece of paper where I wrote them... hope it is not in the bin...

Dmitry67

Oct6-09, 12:42 AM

But do we know what energy is? I mean we do not really progress in labeling things of which we in fact ignore the signification.

All fundamental notions are just mere labels. They don't have any properties per se, all their properties describe their relationships with the other entities.

So the question "what is a true meaning of the Energy" either suggests just another step of an infinite reduction (like energy is made of energions, but in that case energy is not fundamental, so we have the same story again with the "energions") or is meaningless, like asking, "what numbers are made of".

Fra

Oct6-09, 12:57 AM

I couldn't resist adding a comment on one more thing here.

So my question, as you could probably quess, how you can tell a physical system from a purely mathematical one? (this question is not so easy as it sounds)

It seems Dmitry is somewhat into Tegemarks idea of mathematical universe?

In a certain sense I can remotely connect to this, but I still see it different so I could at least comment what I mean with physical and non-physical inferece/math from my point of view because to me it has a special meaning:

Mathematics is the natural language of making quantiative predictions and calculations. So it is even more me of course. However mathematics has also evolved, just like physics. So in principle, there is no major difference. The quantiative framework is often more or less one-2-one to physics. I think Dmitry called it labels? I fully agree so far. I have no problem to imagine the class of all isomorphic constructs here.

One can even think of mathematical calculations as at least supposedly one-2-one with physical actions and processes (or inferences like I like to think of it). so far, that's fine.

So what I mean with non-physical inference, is when one observer; a human in most examples, uses some of his PHYSICAL mathematics, and try to impose it as one-2-one to a much more constrained system with very low complexity.

To me one basic conjecture is that regardless of the CHOICE of represenation or lables, there is an information theoretic abstraction where the COMPLEXITY is the same wether it's mathematics or a physical object, and this complexity constraints what are the POSSIBLE represenations.

What I for example mean is that, it does not make sense to picture a very simple low end computer to actually be able to run a a gigantic algorithem designe for a supercomputer. This is a decent analogy, since I can also accept if we choose mathematics as representation, that physical interactions are like computations. But then the question is which computations are going on in certain processes, and how does the "computers" look like?

This is again just different words for my "inference system". The reason I call in uncertain inference is that the computers themselves EVOLVE _in time_ therefore they change unpredicatably (but controlled) during actualy computations!

THIS is why I don't think it's as simple as deductions. One premise giving one output for example, since during the physical process of producing the output, the calculational machinery responsds to feedback and changes.

So when *I* talk about mathematics, of course all of that is physical for me, as someone noted, at least it's represented in papers, litterature etc. However, if we are trying to impose that very complex logical system into often ARBITRARY small systems, or even points!! then we are abusing the complexity constraints.

Fwiw, I supect this is not going to make any sense, but it's my differentiation. It's exactly this I mean when I object to physical redundance of mathematics, in particular alot of the continuum mathematics.

A final note: What do You think the common say UV infinities are a symptom of?

/Fredrik

Dmitry67

Oct6-09, 03:19 AM

UV infinities are the symptom that distances can not be infinitely small, of course, what else?

Fra, what is more complex: TOE or Standard Model? Or SR/GR? In some sense, TOE is the most fundamental (does it mean that it is more complex?) So, Standard Model emerge from TOE on low energies, like Newtonian physic emerge on our daily life limit.

We are moving from Classical physics to TOE, in opposite direction. But during the history of our Universe the 'laws' 'evolved' from TOE to Standard Model, then even heavy quarks dissapered, then classical physics... I mean, as it cooled down, the laws evolved from TOE to Classical physic.

BUT: if TOE is the most complext one, then laws did not evolve, they had actually simplified!

Fra

Oct6-09, 04:59 AM

UV infinities are the symptom that distances can not be infinitely small, of course, what else?

It was a bit of a rhetorical question, but I meant to link the divergence calcuations with our failuer to see that the inference system - beeing the "calculations" - must scale along with the complexity of the inference systems. So I think it's more than just distance. It can also be interpreted as an "information overflow".

But lets skip this, it was pretty much a rethorical question.

Fra, what is more complex: TOE or Standard Model? Or SR/GR? In some sense, TOE is the most fundamental (does it mean that it is more complex?) So, Standard Model emerge from TOE on low energies, like Newtonian physic emerge on our daily life limit.

We are moving from Classical physics to TOE, in opposite direction. But during the history of our Universe the 'laws' 'evolved' from TOE to Standard Model, then even heavy quarks dissapered, then classical physics... I mean, as it cooled down, the laws evolved from TOE to Classical physic.

BUT: if TOE is the most complext one, then laws did not evolve, they had actually simplified!

I see your reasoning, and it illustrates also the problems you face.

Your "TOE" are necessarily pretty much infinitely complex, from which the observed simplicity follows deductively? You are faced with an enourmous initial value problem, which basically is an infinite improbable initial state. I predict that the tuning problem you are faced with is overwhealming, like the landscape problem in string theory.

The amount of information needed to represent this infinite configuration space and the computing power/time needed to make computations on in would I think stall your progress.

Ie. I do not see how your vision can lead to improved predictive power, because it seems to me you are inflating the COMPLEXITY of your inference system to the point where it violates your own complexity. I thikn only something like a god could make use of your master plan.

BUT: if TOE is the most complext one, then laws did not evolve, they had actually simplified!

I have the requirement of beeing able to make computable predictions. A theory that isn't mangable in the complexity and computability sense simply isn't viable to me. I am taking his seriously in my view.

So in this view, there were no coherent very complex inference systems during this supposed big bang, this is why the complexity you envision (from which simplicity emerged) is not a proper inside view. It's to me an imaginary external view that lacks physical meaning.

So A TOE as seen relative to a human today would be complex, but a TOE seem from the emergent inference systems during say the big bang, would have been very simlpe. Simple mathematics and therefore also simple laws.

The question is instead not how an improbable initial conditions in an infinite configuration space evolves to the probable present, it's how during this process an ARBITRARY initial condition, constrained by a very limited configuration space, INFLATED the configurations space and while doing that evolved new interactions that was originalkly indistinguishable from each other.

/Fredrik

Dmitry67

Oct6-09, 06:49 AM

Fra

Oct6-09, 07:52 AM

Regarding the "improbable initial state" - this is a problem for Bohmians. As you probably remember, I am fanatical MWIer, so for me this problem doesnt exist - Universe started at very simple initial state (probably with null or very simple initial conditions) and the total amount of information in the Universe is probably 0

I have to admit that since I find alot of the MWI reasoning a bit weird, I do not in detail follow the supposed logic there.

But in a certain sense, the "zero information" starting point is not too unlike my view.

However, in my view information can be created and destroyed, if you ackonwledge the intrinsic view, it's just that no observer EXPECTS it, and therefor all stable laws does conserve information. But information conservation doesn't apply to the case where the inference systems is either loosing or gaining complexity.

The zero information in my view, simply means that there are not yet any coherent observers. There is no information because there are no "memory devices" to put it crudely.

"but a TOE seem from the emergent inference systems during say the big bang" - wait, do you deny the existence of heavy quarks soon after the BB? If not, do you think that the laws they obeyed were simpler then the Quantum Chromodynamics they obey now?

This is a difficult question and for sure my ideas are not yet developed enough to explain quark interactions :)

But as a generic "prediction" of my vision, I certainly expext a unification of QCD, electroweak AND gravity. And the inside view of this must be simpler, at least in the sense of explaining alot of the paramters parameters.

At the point where spacetime is emergent, there is unavoidably also emergent inference systsm that I associate with matter or "confined energy" systems. If this is new particles, or some of the existing standard model particles is way too early to see. But if my vision is to make sense, then there must be a level of a simple inference system from which QCD gravity and electroweak follows as the scaling of the inference system complexity/mass grows.

It's just prematute for me to have any expectations on this. But given the formulation of the standard model, as based on QFT, I think the explanation must start already at the emergent of the continuum and dimensions. And to assume that some non-trivial massive stuff like heavy quarks appear in the first part of reconstruction I find quite unlikely, unless they are the FIRST non-trivial systems to emergen as spacetime is formed. But I really can not comment on that at this point.

But it is definitely things that should be answered from a theoretical point of view..

/Fredrik

Dmitry67

Oct6-09, 08:07 AM

The zero information in my view, simply means that there are not yet any coherent observers. There is no information because there are no "memory devices" to put it crudely.

No, system can be infinitely complex - and yet - contains no information!

Take an empty chessboard. It has only 1 possible state, so it contains no information.
Put 1 figure on any of 64 squares. Now you have 64 possible states and it contains some information.
Put 2nd figure - you have 64*63 possible states.
Adding more and more figures, you add more and more information, until.. until you start to approach the UNIVERSUM (in our case it is a full board)
There are only 64*63 configurations with 62 figures, 64 with 63 figures, and only 1 - with 64 figures.

'Something' is equivalent (on information level) to UNIVERSUM minus something.
Empty set is equivalent to the UNIVERSUM and contains no information.

In MWI Universe contains zero information not because it is void, but because it contains all possible states. Interestingly enough, for any frog the amount of information in the universe is huge.

P.S.
It would be interesting to develop a theory of relativity of information. For example, for observer who is aware that 2 particles are entangled, the amount information in such system is less than for an observer who is not aware of it.

ConradDJ

Oct6-09, 08:13 AM

When a complex molecule is simulated on a computer with mathematical modeling, you can see how it vibrates and responds to environment, it looks alive... What we conjecture, that by a similar process we the “physical” become alive because of computation. The only difference is we can see the simulation of ourselves by ourselves without a computer screen.

Can we agree on a simpler statements:

1. If there is a difference between mathematical and physical, that difference can't be tested experimentally by the frogs inside the universe.

2. If universe is perfectly emulated, then frogs can't detect if it is real or perfectly emulated.

3. Perfectly emulated system is isomorfic to a real one.

4. Hence it is absolutely irrelevant if we are emulated or not.

Thanks for the lovely argument! But talking of “simulation” or “emulation” raises an issue that’s much easier to argue than what I was being incomprehensible about above.

There is no analytic solution to a problem as simple as the Newtonian 3-body problem. In other words, if I understand correctly, in a classical universe even very simple physical systems would constantly be finding exact solutions to problems that a computer can solve only approximately – and would be doing so in real time, with no expenditure of energy.

We don’t live in a classical universe, and it’s not clear how that affects the computation problem. On the one hand, the properties of systems don’t have to be specified by an infinite amount of information, and on the other hand the equations are a lot harder to compute.

But I think we can agree that any system capable of emulating the behavior of 3 particles is going to be a lot more complex than the 3 particles themselves, and it has to behave in much more complex ways. And of course, the computation problem becomes vastly more difficult if we have 4 or 5 particles – not to mention the number involved in any realistic physical situation.

The existence of computer simulations makes it easy for us to imagine that we also inhabit a simulation. But it’s easy to see this is really just a fantasy, if you think about the magnitude of the problem involved in, say, computing the paths of individual molecules in 1cc of air over the course of a second. This is something the physical world handles just fine, but no computer ever will.

I think your original idea was not about one system simulating another one, though... it was more like, the world does not need to be “simulated” or “computed” because it already is a mathematical pattern.

ConradDJ

Oct6-09, 08:42 AM

Measurement is described by the physical laws of the Universe.

I would say this is a statement of faith, not fact.

Our closest approximation to a description of measurement is given in quantum “wave-functions” – which are mathematical entities, but rather vague ones. They refer to physical situations in which certain outcomes are possible – but the mathematics doesn’t actually say very much about those situations, it just assumes they are there, and that they can distinguish the various outcomes.

You certainly could not “emulate” a physical measurement-situation in any level of detail, by manipulating the wave-function used in connection with it. The math of QM is a very useful tool for predicting measurement-outcomes, but it doesn’t actually tell us much about what’s physically involved in a measurement.

And of course... the wave–function gives us only a set of probable outcomes, whereas in the physical world we get a random selection of an actual outcome. Yes I know, from an MWI perspective there is no “selection” and all the outcomes are equally “there”. In other words, in the big picture measurements don’t actually happen, and the wave-function is the complete picture. But this doesn’t get us closer to mathematics and physical laws describing what happens in a measurement.

From the perspective of any observer in any universe, the world is constantly offering up new facts that could not in principle be predicted on the basis of prior facts, and which often have profound consequences for what can be observed in the future.

So I think mathematics gives us wonderfully effective partial representations of many different (highly simplified) aspects of the physical world. If we take any small part of a measurement-situation, a photon or an electron, say, we can give a good mathematical description of it. But that doesn't mean we've described the structure of the situation as a whole, or described how it does what it does.

I don’t doubt that our ability to model more and more of the world mathematically will continue to improve. But the leap to the idea that mathematical structure per se explains what’s going on in the world is a long leap of faith... or maybe, a default position based on the difficulty of imagining alternatives.

It’s not clear what’s going on in quantum measurement-processes... but to me, MWI just offers a nice way to avoid dealing with the problem. That’s a sensible choice to make based on a faith that the world is mathematical, and that issues we don’t know how to frame mathematically can’t be really important. But I don’t believe there’s a strong argument there.

Fra

Oct6-09, 08:59 AM

No, system can be infinitely complex - and yet - contains no information!

I know what you mean, but then your certain information measure and state space is a baggage. This baggage carried background information in my view. So your information measure is "relative to" the context, which is fixed in your view.

I don't think there is an innocent background, in my view the context is evolving. Therefore there exists a feedback between information, and information carrier.

I know you can define microstructure of infinite size, and an information measure. Then zero information is simply the equipartitioning.

But the ergodic hypothesis is not unique, this choice does carry background information. In my view I am trying to account for this.

This is why I also talked about a reconstruction of information theory, which is pretty much on the same table as the reconstruction of probabiltity theory.

The ambition is exactly a theory of relativity of information (and inference) that you mention! So if you like that, then there might be some grains in here that you can like as well. Now, I think a theory of relativit for information necessarily evolves, because there exists no static fixed solutions. The inference processes resulting from this relativity, are physical ones, that possess things like inertia etc in my view. This is how I intend to extract physics from the actual inference process, and the evolution of matter (and distinguishable law) from the evolution of infernefce system, by the requirement of preservation. "Consistenctly inconsistent" systems are not present in the equilibrium "population", however "transient inconsistency" is unavoidalbe and part of the evolution/development.

Edit(with regards to post 331): The connection to the holographic principle is an interesting lead, there is actually some interesting connections to that and to my abstraction of inference system, but currently I'll be away for some days and it's unclear wether I will have any internet access. There is actually a mathematical abstraction of an inference system, and in there there is something you can call a communication channel, and this has as size measured by the distinguishable states. This "size" or area, together with some other stuff, like the information capacity on one side of the "screen" limits the inferrable information of the other side. But this is a pure abstraction so far, the screen is not interpreted as a space-area. OTOH, this would clearly turn into something interesting as spacetime emerges. This is one of the things I'm working on and it's not yet finished. But there are at least potentially very interesting links.

In particular am I interested in finding information theoretical interpretations to several constants.

About overestimating information, that is also an interesting direction of discussion.

/Fredrik

Dmitry67

Oct6-09, 09:44 AM

The ambition is exactly a theory of relativity of information (and inference) that you mention! So if you like that, then there might be some grains in here that you can like as well.

I have 2 questions to that future theory - may be someone can give a reply?

1. As I mentioned, when you look at 2 particles you overestimate the amount information in that system, if you unaware of the fact that these particles were entangled. But in the past many particles had interacted somehow, so they are mutually bound by some conservations laws, and further in the past we look, the more bounding interaction we find.

The question is, to what extent do we overestimate the amount information in the typical system? Is it near 0 if we go back to the BB?

2. Based on the http://en.wikipedia.org/wiki/Holographic_principle
the amount of information in a given volume in proportional to the surface of the boundary of that region. Specifically, to the number of Planck-size 'pixels'.

The interesting thing is that if you increase the radius by 10x, the volume grows as 1000x, but surface (and information inside the region) grows as 100x. So average information density per voxel (volume pixel) decreases as you increase the volume!

On the bigger scales Universe becomes more and more primitive. We started to draw these spheres from the Earth. But it is illogical to assume that Universe in complex here but is more and more primitive far from us - there is no center of the universe.

So looks like the only option is to conclude that on large scale regions of the Universe start to repeat themselves.

qsa

Oct6-09, 12:58 PM

Thanks for the lovely argument! But talking of “simulation” or “emulation” raises an issue that’s much easier to argue than what I was being incomprehensible about above.

There is no analytic solution to a problem as simple as the Newtonian 3-body problem. In other words, if I understand correctly, in a classical universe even very simple physical systems would constantly be finding exact solutions to problems that a computer can solve only approximately – and would be doing so in real time, with no expenditure of energy.

We don’t live in a classical universe, and it’s not clear how that affects the computation problem. On the one hand, the properties of systems don’t have to be specified by an infinite amount of information, and on the other hand the equations are a lot harder to compute.

But I think we can agree that any system capable of emulating the behavior of 3 particles is going to be a lot more complex than the 3 particles themselves, and it has to behave in much more complex ways. And of course, the computation problem becomes vastly more difficult if we have 4 or 5 particles – not to mention the number involved in any realistic physical situation.

The existence of computer simulations makes it easy for us to imagine that we also inhabit a simulation. But it’s easy to see this is really just a fantasy, if you think about the magnitude of the problem involved in, say, computing the paths of individual molecules in 1cc of air over the course of a second. This is something the physical world handles just fine, but no computer ever will.

I think your original idea was not about one system simulating another one, though... it was more like, the world does not need to be “simulated” or “computed” because it already is a mathematical pattern.ConradDJ, solutions for differential equations or results of computing any algorithms are already there (that is exactly our point), so you are right in your last sentence. When we talk about us computing (simulating) we are trying to simplify the bizarre notion that existence is mathematics, and people have hard time accepting. As for accuracy, physicists say that in principle any classical problem can be solved accurately, even throwing a dice. You can do numerical solution and find out to any arbitrarily high accuracy provided you have formulated the problem correctly. Formulating the problem is a different issue, it is basically a human intelligence (and logistic) problem, not fundamental.

As for the accuracy of QM and the formulation issue, now you are talking about the really interesting part, which may bear directly on the postulate of math&reality. QM theory is very accurate –up to experimental set up accuracy-, but QFT is a different issue all together. The rapping about TOE in PF is all about not knowing a good (final) theory that describes nature. For me (I know people will through anything close to them on me now), the unification of forces and particles is not the biggest issue. I will not settle for anything less than complete description of interactions, be it one or many particles (with gravity, high-low …etc). The problem is that in QFT the operators are no more representing observables as in QM but the particle creation/destruction representation, the wave function represent the probability of creation/destruction and so on. The spatial information is lost. I don’t know why this issue has not been raised (it is difficult because SR is involved). But my program http://www.qsa.netne.net has the first very modest attempt at tackling this problem. Of course, most attempts at TOE are been concentrated in the Regularization/Renormalization problem, just aspirin if you ask me. Although, if somebody was suffering from a brain tumor and no cure were in sight, aspirin will do. If we are able to model reality in a highly accurate way, I would say we will be 80% (or 100% who knows) there to the theory of “existence is mathematics”. I can elaborate, but I think it is prudent to stop.

Fra

Oct7-09, 02:05 AM

1. As I mentioned, when you look at 2 particles you overestimate the amount information in that system, if you unaware of the fact that these particles were entangled. But in the past many particles had interacted somehow, so they are mutually bound by some conservations laws, and further in the past we look, the more bounding interaction we find.

The question is, to what extent do we overestimate the amount information in the typical system? Is it near 0 if we go back to the BB?

I think we approach this in different ways. Entanglement and particles, conservation laws etc makes me think of the standard QM or QFT framework. Since I consider the notion of information we have in that framework to be inappropriate my reasoning doesn't start from that, I'm focused on finding a coherent framework.

For me, a measure of information is only defined differentially and locally with respect to an observer, so that the information defines a differential evolution (by the action). The feedback from a definite evolution, sometimes not only revises the information but also the information measure itself.

To see a link between GR and a relativistic theory of information here is a association:

When I insist that all information is inferred, I am suggesting a link between inference system and the information state. A link between state and "law" of change, if you like. This connection as I see it, defines a self-evolution. This self-evolution is pretty much the correspondence of a geodesic. Ie. given no conflicting information or unexpected interactions, the systems evolves as per a sort of geodesic in hypothesis space.

Even when the geodesic is curved, with respect to another observer, the inside view is still that it simlpy follows the geodesic. However, there will be differential forces that curves the inference system during a definite progress.

So, the inside observer does not perceive it's own path as curved, because the curving is a natural process where new information updats the expectaion of what the self-evolution is like.

So the inside view is just evolution in the forward direction, but where there is a new forward direction after each step so that the direction is always straight as judged from the inside. The inside view is that of evolving inference system.

Now, consider a second sufficiently complex obserer observing this from an external position, he will instead infere that there is a law that describes how the first observer deforms. Given the correct circuumstances about complexity of the second observer and ability to monitor the first sstems environment, then the first systems "inside evolving law" can be consistently described by fixed laws with respect to the second observer.

There is no conflict here. So in effect, there are dualities here when you transform between observers, you also transform the laws, but to find THAT transformation you need yet another third observer :) and he has to be even more COMPLEX to be able to infere with certainy this transformation. This is the sene where I insist that symmetry transformation are emergent, and the complexity of systems limits to what exten this is possible. When the limit is reached, the remainder are simply evolving law, wether we like it or not.

Now for me the whole point is that seeing how the real inside view is like, we can actually understand it's ACTION better, if you use the rational action conjecture which suggest tha the action take is the one that is minimally speculative from the point of view of self-preservation.

This complexity constraint also explains STABILTY in a remarkable way, because to a bounded system, it's action is CONSTRAINED by the fact that from our point of view not all "mathematically realisable" possibilities are distinguishable! And to such a system the rational action conjecture of mine required the action to be invariant with respect to those possibilities!

This means these "paths" simply aren't part of whatever inference calculation you have, feynmann style path intergral or similar.

This means that the inside-actions, or naked actions of any system is BOUND to get simpler and simpler as it looses mass. But the external view is still complex, because the baggage there is physical with respect to the outside observer, but most of that baggage is something the system of study is invariant to. So in order to know what symmetres to apply, to get rid of the redundancy this idea will certainly help. Since it contains clear ideas and clear constraints. But it's still complicated of course.

This link I am suggesting, is totally absent in the standard framework, and this link is IMHO at least what makes the information theory including a sort of feedback to the context, and thus making it intrinsically relative; rather than just relative in the sene of a fixed relation with a kind of god-like background.

/Fredrik

qsa

Oct7-09, 10:40 AM

ConardDJ, here is a website link that gives an interesting argument about physical and non-physical which gives a hint of what we have been talking about. The author is an excellent QFT teacher plus he has many unconventional research.

http://www.scientificexploration.org/journal/jse_14_2_klauber.pdf

jal

Oct7-09, 08:59 PM

update:
http://www.interactions.org/cms/?pid=1028531
Media information for LHC running in 2009-2010

tom.stoer

Oct9-09, 01:54 AM

Can we agree on a simpler statements:

1. If there is a difference between mathematical and physical, that difference can't be tested experimantally by the frogs inside the universe.

2. If universe is perfectly emulated, then frogs can't detect if it is real or perfectly emulated

3. Perfectly emulated system is isomorfic to a real one.

4. Hence it is absolutely irrelevant if we are emulated or not. In fact, the emulation is an argument for MUH: if there are universes which can emulate others, then all sorts of universes MUST exist

If we agree the theory of natural numbers is the same no matter if it is written by ink, or in PDF, or scratched on a stone, so mathematics is independent from the substance, then we must agree that it is irrelevant if it is emulated or not.

...

This is also an answer to tom.stoer (1,2,3,4)

I see your point. It seems rather straightforward but I still have problems with it.

Do you know the "Chinese Room" from Searle? Let there be a a room with a Chinese person locked inside and answering questions written in Chinese language. Now replace the chinese person with an english speaking person equipped with Chinese books and procedures written in English how to use them. Again you hand over questions written in Chinese language - now to the "room", not directly to the person. Assume that the questions and written answers are the same as before.

Question to you: in the latter case, who does really understand the Chinese language: the room, the system "room + books + person"? My answer would be neither, it's the person who prepared the experiment, wrote the books and procedures and set up the experiment!

Of course you can refuse to comment on this because it's not really a question regarding ToEs or physics in general but a question regarding consciousness, the mind-body-problem etc. You can respond that the emulation is not perfect. I don't claim that this analogon is perfect - far from it. I only want to illuminate why I still have problems to accept your statements 3 and 4. If two systems are isomorphic that does not automatically imply that they are identical. You can interpret this as mathematically identical, but not necessarily as ontologically identical.

Tom

Dmitry67

Oct9-09, 02:34 AM

Of course, "Chinese room" depends on if you accept "Strong AI" or "Weak AI" hypotesis. But your argument is a good one. The only difference between 'real' and 'unreal' universe could be in the solution to the "Hard problem of consciousness", so 'unreal' universe can contain nothing but P-zombies.

tom.stoer

Oct9-09, 06:56 AM

what are P-zombies?

Dmitry67

Oct9-09, 07:02 AM

check: http://en.wikipedia.org/wiki/Philosophical_zombie
it is closely related to the "Hard problem"

tom.stoer

Oct9-09, 04:02 PM

Gear300

Oct9-09, 05:30 PM

When is it that the LHC will start operating at or near its highest energy?

Dmitry67

Oct10-09, 01:26 AM

OK, I agree that the Chinese room and the P-zombies are somehow related. I repeat my question: in the case of the "Chine room", who does really understand the Chinese language: the room, the system "room + books + person"?

Answer: entity "room + books + person"

Imagine human brain enlarged to a size of a city: you will be walking on the 'streets', looking at working neurons, asking: but WHAT EXACTLY is responsible for the qualia?

Imagine some conscious microbes-scientists living in your body. As scientists they will discover many interesting patterns: for example, activity during the day is higher then during the night, there is a strange 7-day pattern, when some signals (pain) comes into brain, soon there is a response sent to muscles. They will study cells and neurons, and they will get a lot of information about them. But they will not believe that all these neurons are conscious. As that consciousness is on another size and time scale, they will not be able to communicate with that conscious.

In fact, I am sure there is ALREADY a sort of cheneese room: it is a network of 2 types of nodes: Internet + humans. Human work not only as nodes, but also as senses: photocameras, youtube, forums, etc. They also process that information (by typing a word in Google pictures you can see how any object look like even there is no object recognition software)

'Thoughts' of that system exist in form of blog posts, emails, etc. Some fade, some spread over the whole network (much slower then we think, so it is on a different timescale). For elementary nodes (us) everything in that system is reducable to some elementary facts: emails, characters in the blogs etc. So it is very easy to deny the existence of somethign extra. It is very easy to say: "there is nothing except us - humans, computers and the link between them".

But it is exactly the cheneese room argument, or saying that there is nothing except the neurons in a perception of the microbe-scientist in our body. So I am sure that superconsciousness already exists on Earth but we will not be able to communicate with it, because it is on a different scale.

tom.stoer

Oct10-09, 03:48 AM

OK, that's where I have a different opinion. For me the knowlede regarding Chinese language somehow disappeared from the system. I would say that it's not system "room + books + person", but the person who prepared the experiment.

Now let's come back to TOE: the question was if a mathematical system that is equivalent (isomorphic) to the universe, is identical with the universe. Again that's where we differ. I would say that I believe in some metaphysical entity which IS the universe (object, entity, stone, human, ...). A mathematical system being isomorphic to that universe is still different.

You can turn it the other way round and state that mathematics exists w/o any physical existence. Let's come back to my simple universe with only gravitational law. I do not believe that it exists in a physical sense "anywhere", but of course it exists in a mathematical sense. Therefore mathematical existence transcends physical existence.

I think there is nothing illegitimate or contradictory in your reasonung; it is simply the fact that I am not (yet) prepared for the dark side ...

friend

Oct10-09, 09:53 AM

Now let's come back to TOE: the question was if a mathematical system that is equivalent (isomorphic) to the universe, is identical with the universe. Again that's where we differ. I would say that I believe in some metaphysical entity which IS the universe (object, entity, stone, human, ...). A mathematical system being isomorphic to that universe is still different.

The universe is something we observe or measure. Mathematics is something we calculate. The mathematics would be a kind of language or description of the universe. And no equation we could write would account for every single particle or field at any time. We use math to figure out different configurations or general features that we are interested in. Math only tells us that given some input some output results. It doesn't tell us that a given input IS the case.

tom.stoer

Oct10-09, 12:36 PM

thanks

Dmitry67

Oct10-09, 12:55 PM

qsa

Oct10-09, 06:03 PM

Friend, the initial condition issue is a side advantage of the idea, and it is being explained as there is no need for it, for the theory is multiverse and all possible configurations are possible.

As to you tom, you have made the most beautiful statement so far in this discussion

“You can turn it the other way round and state that mathematics exists w/o any physical existence”

But if that is true, how this mathematical existence does manifest itself? It can not hang in thin of nothing and exist. Well then, I don’t need to repeat how its existence is manifested.

qsa

Oct10-09, 06:49 PM

tom
As to the isomorphic issue you can look at it from different perspectives, I’ll give the easy one and leave the harder one to later. If I do have isomorphism then I can go to a computer and program the properties which I discovered and plot them so to speak, i.e. simulate. Notwithstanding accuracy and computer time issues, and so on. Let’s assume we can approximate and maybe we get a universe that small numbers of galaxies and algae appear. That would give you a strong hint, wouldn’t it? Now, if you get in argument with me about if a computer has enough power or the accuracy needed, then you have to admit that isomorphism issue was put on the shelf by you.

moniker2

Oct10-09, 07:29 PM

tom.stoer

Oct11-09, 02:40 AM

tom.stoer

Oct11-09, 03:04 AM

... you have made the most beautiful statement so far in this discussion

“You can turn it the other way round and state that mathematics exists w/o any physical existence”

But if that is true, how this mathematical existence does manifest itself? It can not hang in thin of nothing and exist. Well then, I don’t need to repeat how its existence is manifested
It can. Or better: it need not manifest itself.

Let's make some simple examples:
Assume the twin prime conjecture is false; then there is a largest twin prime. Does this number EXIST even before anybody KNOWS its value?
Before the discovery of quantum mechanics and the work of Hilbert: Do you think that Hilbert spaces already existed 200 years ago?
Continuum hypothesis: as we now know both its proof and its disproof are impossible in ZFC. So there is the possibility that there exists sets S with cardinality |N| < |S| < |R|. Do you think that such a set EXISTS even if there is no construction?

I would say that modern mathematics provides some strong hints that its entities, theorems and other contents may exist w/o any physical manifestation. For me mathematics exists w/o physical representation (brain, paper, computer, ..., universe in the sense of MUH). But again: this is my belief and there's neither a proof nor a disproof.

Dmitry67

Oct11-09, 03:28 AM

What if indirect arguments for MUH are true, say,

When TOE is discovered, it will be possible to write it without any word "baggage" and derive everything else from scratch;
Initial conditions are null

Would it help you to believe in MUH?

tom.stoer

Oct11-09, 09:41 AM

It depends on the structure of that ToE.

If it is a "unique" framework containing axioms, theorems or something like that which indicate what I used to call "selection principle" then I would believe in the ToE but NOT in MUH.

If the ToE is a framework for producing theories together with a hint (I do not know how it can look like) that at least our universe (plus some others) can be derived, then I would start to believe in the existence of these other universes.

If the ToE is only the meta-framework and a statement that all consistent mathematical frameworks are physically existent "somewhere", then I would say (because the selection principle or hint is missing) the ToE (which is identical to MUH) is meaningless or empty and I would call it ToN.

=> I cannot answer your question unless I have an indication how that ToE would look like.

friend

Oct11-09, 10:42 AM

Correct me if I'm wrong, but it seems all mathematical formulae are hypotheticals,..... meaning, IF you have some input, THEN you have some output. And so mathematical descriptions apply just as easily to fictitious situations as to real situations. You can just as easily calculate the trajectory of unicorns as to cannon balls. Math makes no distinction between fact and fiction.

Dmitry67

Oct11-09, 01:17 PM

IF you have some input, THEN you have some output. And so mathematical descriptions apply just as easily to fictitious situations as to real situations. You can just as easily calculate the trajectory of unicorns as to cannon balls. Math makes no distinction between fact and fiction.

No, no, and no!
friend, what input is used to develop a theory of natural numbers? If it uses some input then you probably can provide another theory of natural numbers, where number 19 is not prime?

your unicorns vs cannon balls is just a variation of an argument about the initial conditions I answered before.

friend

Oct11-09, 01:34 PM

No, no, and no!
friend, what input is used to develop a theory of natural numbers? If it uses some input then you probably can provide another theory of natural numbers, where number 19 is not prime?

your unicorns vs cannon balls is just a variation of an argument about the initial conditions I answered before.

Dude, do you honestly think you're going to find a theory that tells you the position and momentum of every particle in the universe, even those behind the cosmological event horizon? Are we going to find a ToE that predicts the human form with the right number of fingers, toes, eyes, and even my individual hair color? Will it predict all of human history? I seriously doubt that. I think the best to be expected is to determine generalities that describe what kinds of things are possible. And by definition generalities give you results based on input that is not determined by that generality. It's even worse, we'll probably only get at best a range of probable outcomes given an input. That doesn't sound isomorphic to a reality which definately IS.

Dmitry67

Oct11-09, 01:43 PM

friend, are you aware how MWI deals with these issues? multihistory theories can be deterministic but look random for all observers

friend

Oct11-09, 02:02 PM

friend, are you aware how MWI deals with these issues? multihistory theories can be deterministic but look random for all observers

I think the MWI is nonsense. If some other possible universe does not have any affect on us, then it does not exist as far as we are concerned.

This MWI came about to explain the alternative paths in Feynman's path integral. But the formulation predicts that it takes ALL possible paths to make a reality. That means none of them exist apart from each other.

Dmitry67

Oct11-09, 02:10 PM

Yes, all these branches exist. Looks like your argument is just an emotional one, because you are aware that MWI is consistent with the observations.

So I will reply you on the emotional level. Do you see how elegant MWI is? Look at a list of QM interpretations asking a question about the initial conditions.

In our world symmetry is broken many times. Random interpretations (CI, TI) do not have any problems with it, they can start from null initial conditions, but they are hated for being non-deterministic.

Deterministic interpretations (BM) look weird because they mean that I, typing this text, was pre-coded in the positions of the particles in the Big bang.

MWI is *the only* deterministic theory which can start from the null initial conditions (and multihistory is the price you have to pay for they wonderful combination)

qsa

Oct11-09, 07:04 PM

The universe is something we observe or measure. Mathematics is something we calculate. The mathematics would be a kind of language or description of the universe. And no equation we could write would account for every single particle or field at any time. We use math to figure out different configurations or general features that we are interested in. Math only tells us that given some input some output results. It doesn't tell us that a given input IS the case.

thanks

It can. Or better: it need not manifest itself.

Let's make some simple examples:
Assume the twin prime conjecture is false; then there is a largest twin prime. Does this number EXIST even before anybody KNOWS its value?
Before the discovery of quantum mechanics and the work of Hilbert: Do you think that Hilbert spaces already existed 200 years ago?
Continuum hypothesis: as we now know both its proof and its disproof are impossible in ZFC. So there is the possibility that there exists sets S with cardinality |N| < |S| < |R|. Do you think that such a set EXISTS even if there is no construction?

I would say that modern mathematics provides some strong hints that its entities, theorems and other contents may exist w/o any physical manifestation. For me mathematics exists w/o physical representation (brain, paper, computer, ..., universe in the sense of MUH). But again: this is my belief and there's neither a proof nor a disproof.

Tom, I can debate about the nature of math and what it means when and where, but I have a more usefull comment

Tom, if you say that math can exist without physical, but physical is there and we find math in it (even worse, it is the only language that describes it). Doesn’t that strike you as odd coincident? Einstein put it in this way “the only thing that is incomprehensible about reality it is that it’s comprehensible” .What I mean is that math could have existed without physical but it had to appear with physical, and then describe physical, hmm.

tom.stoer

Oct12-09, 01:29 AM

I don't think it's coincidence.

I agree to some statements in this thread that reality must follow some basic rules of logic (perhaps more complex than classical logic, e.g. due to quantum mechanics).

I would say that if nature represents some rules of logic this implies that it must represent all fields of mathematics that emerge from logic. As logic (+ set theory) leads automatically to natural numbers, it is not too strange that we find natural numbers in physics

I do not know why nature has chosen to exist in some other (more complex) representations of certain fields of mathematics. Classically nature represents (in addition to natural numbers) certain manifolds etc. Quantum mechanically it represents Hilbert spaces. I do not know why Hilbert spaces and not some more general Banach spaces - or something totally different.

Perhaps these more complex structures are a hint that we must focus on the derivation of the complex physical structures from more simple ones; that would mean that nature encodes or represents something like the emergence of mathematical frameworks in certain limits, but that the basic laws are quite "simple".

In that sense some ideas of modern physics are definitly going into the wrong direction. Strings are certainly not the building blocks as their fundamental laws seem to be quite complex (nobody knows them today). Loops are closer to this idea, but still too complex (the simplest framework seems to be a certain spin foam model, but still this requires complex reasoning). I am not an expert but causal sets could be a step into the right direction.

In the very beginning I said that MUH seems to be quite strange because it replaces the quest for a fundamental matehmatical principle with the statement that there is no such principle ("all mathematical frameworks do exist"). I guess that there must be a basic principle, a selection rule or something which - together with a rather simple mathematical framework - allows nature (description of nature) to emerge from these fundamental entities. This principle would be a physical principle in the sense that it appears as a mathematical axiom = something w/o proof = something you have to believe in.

I know thta this idea does not mean that you can get rid of all human baggage as we called it. In addition it does not explain why nature respects logic (or logic plus some entities, principles, ...). It does not explain why "this principle" and not "that one".

But I see this as a rather modest step towards a "ToE".

Dmitry67

Oct12-09, 01:45 AM

I guess that there must be a basic principle, a selection rule or something which - together with a rather simple mathematical framework - allows nature (description of nature) to emerge from these fundamental entities. This principle would be a physical principle in the sense that it appears as a mathematical axiom = something w/o proof = something you have to believe in.

tom, can you imagine a different universe where intelligent observerse can evolve?

By the different universe I mean universe with different laws: say, 4 generations of quarks, or even more dramatic differences, like, more macroscopic dimensions, absolutely different laws?

I know that MOST of physical laws provide 'bad' universes. This is called a fine tuning problem. So 'good' universes are VERY RARE. But are you saying that our universe IS THE ONLY POSSIBLE ONE (mathematically) where intelligent observers can evolve?

P.S. I know you distingusih "EXISTS" and "CAN EXIST". My question is not about if alternative 'good' unvierses EXIST, but if you agree that they CAN EXIST.

tom.stoer

Oct12-09, 06:20 AM

That again depends on the ToE and its ontological interpretation.

If the ToE provides a rather restrictive framework which e.g. fixes the charges, coupling constants and generations, then I would say that only our universe EXISTS.

If the ToE provides a less restrictive framework than we can still speculate that different universes CAN EXIST w/o the ability to prove or disprove if they REALLY EXIST.

If the ToE provides a hint how a multiverse with evolving or somehow different laws in different universes could look like and how these different universes can be spawned from the multiverse, then I am willing to accept that these universes DO EXIST. This spawning must happen in our universe, i.e. it should have (at least in principe) physical effects; if it takes place "outside" the universe = w/o any feedback I would still say these additional universes CAN EXIST.

But we are coming back to the discussion we had several weeks ago: I think that physically the lack of a fundamental principle (selection, uniqueness, ...) is a weakness, whereas in your opinion its a strength. Btw. - and to avoid a discussion regarding Ockham's razor: our positions are not differing regarding the number of principles we have, they are only differing regarding the type of principle:

My yet to be discovered PHYSICAL principle will select a ToE and therefore a (class of) EXISTING universe(s) from all possible mathematical frameworks.
Your ONTOLOGICAL principle says that everything which can be cast into a baggage-free mathematical framework DOES EXIST in reality.

Therefore we do not so much differ in the application of Ockhams razor but in the very nature of the principle itself.

Dmitry67

Oct12-09, 06:42 AM

Yes, I was trying to avoid discussion about the EXISTS/VS CAN EXIST, but you replied on that. And I wanted to talk about the mysterious "selection principle"

Ok, my turn anyway.
Imagine that neutron decays instantly. It would be fatal for stars and life. It is an example of HARD selection princliple, some kind of no-go for lide. HARD selection principles limits the conditions and universes where the life can evolve. We both agree that such principles do exist

But I was asking if OTHER universes where life is possible can (mathematically) exist.

To be consistent, you have a choice:

1) You can say: NO, only OUR Universe favours life, in all possible axiomatic systems which define laws one can in principle imagine life can not evolve!
So saying 1 you can claim that the selection principle is a HARD one. Even I see that option as very unlikely this is verifiable, as the principle is HARD.

2) If you dont claim that, then you agree that some can invent a mathematical framework where some other intelligent beings can exist. Say, universe with intelligent snakes, built from Singularium - an element which consists of 23 arba and 17 kadabras. Now the question is, how any selection principle can favour US versus intelligent snakes?

Lets call that selection principle a 'SOFT' one because it does not exclude all possible unverses except the only one (ours), it just says that ours is better

What option do you chose? HARD or SOFT? If SOFT, then why our universe is better? Can soft principle be something better then 'God hates snakes and preferes ebings with 2 hands built from Carbon'?

friend

Oct12-09, 10:41 AM

....I guess that there must be a basic principle, a selection rule or something which - together with a rather simple mathematical framework - allows nature (description of nature) to emerge from these fundamental entities. This principle would be a physical principle in the sense that it appears as a mathematical axiom = something w/o proof = something you have to believe in.

I know thta this idea does not mean that you can get rid of all human baggage as we called it. In addition it does not explain why nature respects logic (or logic plus some entities, principles, ...). It does not explain why "this principle" and not "that one".

Could it be that the physical principle that selects which logic physics can be derived from is this: a logical conjunction of facts. In other words, whatever there might be, if physical facts exist, then they must co-exist together, not one contradicts any other. They exist in conjucntion. That sounds like a physical requirement imposed on whatever logic determines reality. Or is there other kinds of math that require a set of elements which exist in conjunction?

Fra

Oct12-09, 04:15 PM

I have a feeling that I have made my position clear enough already but...

Could it be that the physical principle that selects which logic physics can be derived from is this: a logical conjunction of facts. In other words, whatever there might be, if physical facts exist, then they must co-exist together, not one contradicts any other. They exist in conjucntion. That sounds like a physical requirement imposed on whatever logic determines reality. Or is there other kinds of math that require a set of elements which exist in conjunction?

It sounds almost like a physical version of Hilbert's vision?

Gödel should suggest that you can't be both complete and consistent, suggesting something is wrong with your vision?

Unless, you consider (like I do) that that selection of logic, and the inferences of laws are themselves processes that are one-2-one with physical processes that do occur in nature, at non-human generic system level.

This way, the problem is not how to find a complete set of consistent axioms, but rather to describe how a set of axioms actually are constrained to EVOLVE, BECAUSE of the fact that it's either inconsistent or incomplete, or both.

This is how I see it. If I am to project my thinking onto what you guys are doing, I would say that I am looking not for an axiom system, but to understand how and why certain axiom systems are selected, and how they rationally respond to inconsistencies and evolve into others.

I ponder question like, how to make sense out of a conjuction of two inconsistent facts, in a way that the end result is again in some sense "consistent".

If you see this in what I think is the wrong way then it makes no sense. A conjuction of two inconsistent things simply result in a halt.

However, if you look at a inductive inference model, then it can be that the prior and the new evidence really signal different things. The result is a rational revision which results in a new posterior.

Let me take another intuitive example, if a human makes inferences that repeatadly proves to be at variance with observations, then any rational human would start to doubt his own inferences, and revise the inference system itself.

There are different kinds of "logic". Why does the deductive and axiomatic type of hard logic seem so obvious and unique? For me, the crispness and apparent decidability of that logic is easily deceptive; something of which Gödel's theorem gives some good hints. I think Tom already considered this problem - the question is; what is the resolution?

More general inference systems such as inductive and fuzzy logic are IMO more powerful, and renders the deductive logic as a special case of more general forms of logic.

I think you are stuck in insisting on a particular form of reasoning. I can't see another way out of there but to start to see that "logic" is not necesarily unique. I think that's a deception :)

/Fredrik