So what about the FQXi time essay contest? It's February already.
|Mar20-09, 01:46 AM||#52|
So what about the FQXi time essay contest? It's February already.
One obvious problems is that some of the new lines of reasoning is so radical that alot of the standard notions which the well tested standard model rests on needs to be reconstructed, which means this is cumbersome. So for sure, in the short run it seems easier to find a tweak to the current models, that to aim for a total reconstruction.
There are some people doing different things, but which has elements of what I think is new thinking, but there isn't yet a coherent direction that I know of.
Like Niels mentions in his description, a mainstream idea is to look for symmetries under which the physical actions are invariant, and then as we do so, identify new forces and particles. Then unification usually means looking for the bigger über-symmetries that unify all previously known symmetries and provide unification.
I think this is a absolut twisted way of doing it, I think it's flawed. Holger seems to also object this this general way of reasoning. If you ponder how to infere this über-symmetry, from a plain communication, then I think it's quote clear that a different angle is needed. The symmetry must be emergent.
Holger talks about the random planck scale, and I might reason differently by one idea is that at the say "planck-scale", there maybe be so chaotic, that no observer can SEE the fully symmetries. The symmetry is only seen by a massive observer.
Instead of starting with symmetries, pictures mathematically without clear physical basis, I think we can start with "random actions", and from this picture, the complexity scale LIMITS the POSSIBLE symmetries. Complexity scale and energy scale are related, sometimes inversly, it depends on where you picture the observer is. ie. if you talk about plackscale, are you talking about a human lab probing the planck scale in an future hyppthetical accelerator (which wont happen soon anyway) or are we picturing an actual observer living in the planck scale. My starting point is tha latter, and then the random action is the decent abstraction.
To me there are two main points here.
1) To emphasise the "inside view", to a larger extent. In a certain sense the traditional symmetry arguments is really an "external view" of how the "inside views" RELATE, by symmetry transformations. But not that this implies a third observer, a birds view. This is not a coherent analysis IMHO.
Someone who seems to start to take this more seriously is Olaf Dreyer. Look him up. He has sometthing he calls internal relativity. He has some good way of reasoning IMO.
Rovelli's Relational quantum mechanics paper also has some good start, but rovelli gives it a different turn which IMHO breaks the coherence. But the initial reasoning is good.
The birds view must go away. It's an ugly duckling :)
2) The evolutionary perspective, that we must stop pretending that realistic models can be made on closed systems. To model open systems, evolving models are needed Ithink. Here Lee Smolin with his CNS, and several of this talks presents many good arguments in favour of this.
To me, these two ideas marry very well. And I think their combination is the key. But together the imply a dense reconstruction of what most physicists consider "basic formalism". So it's probably a long term project.
|Mar20-09, 02:39 AM||#53|
Unfortunately I haven't had time to read that yet, but I iwlll
(Just to get back on topic here, sorry for the diversion)
|Mar20-09, 05:13 AM||#54|
From the point of view a true inside observer, simplicity is restored in the middle of the chaos. A human designed accelerator probing the planck scale doesn't quality as an inside observer. Because the whole measurement setup, is rigidly attached to a massive environment, that is largely controlled. Some logic that works fine in such cases, may not work the the inside observer scenario.
Cosmological scenarios is more like the inside observer case.
This is why the treatise of statistics, and probability must be drastically different in particle physics as compared to say cosmological theories.
But not only that, I think that acknowledging the inside view, is also they key to understand the LOGIC even of the standard model of particle physics. Ie WHY does the actions look like it does, why do we see this mass spectrum and not anything else.
After all, from the point of view of the particles themselves, they are inside observers totally unaware of human accelerators. I expect the rational behind the laws of particle physics to exists in that view.
So the inside view, does not only become relevant for cosmology. I am personally more interesting in it's applications to the logic of the laws of physics in general. Including the tuning problems etc.
As far as I currently see I think an evolving universe with evolving laws is the only reasonble solution. But evolving universe on cosmological scale such as black hole reproduction, and the reproduction, copying and evolution of "compression" algortighms that encode the action of microphysics really are another perspective of the same process.
|Mar20-09, 05:39 AM||#55|
But there are still two radically different ways that this same observed outcome could be achieved. There may have been one unbroken most general symmetry that crumbled in a cascade of symmetry breakings to reach its lowest energy incarnation. Or the different thought. there could have been an unformed chaos of potential (hand-waving here for the moment) which fell into all available symmetry "slots". Bit like a rain of pachenko balls getting hung up at various available levels.
So the first way of looking at it would demand some super-symmetry. All the observed symmetries of the standard model would have to fold back neatly into the one E8xE8 or whatever. And we know that project is not working so well.
The second way would instead say that all the various symmetries would not have to be related in this fashion. They would not have to heal to one super-symmetry. Instead, they culd just be the collection of symmetries that (somewhat platonically) exist as resonant forms. And any cooling of chaotic potential would congeal in the various slots to various degrees.
This is a very untechnical description but it is a sketch of an alternative story that could result from taking an approach along the lines Nielsen seems to be exploring.
You say the symmetry must be emergent. This other view would be saying the broken symmetry - the crisp result - is emergent! And the ultimate symmetry never existed. The evolution (or rather development) is from the formless to the formed.
Now you would have to call that a very twisted view. But it is like a phase transition approach. Symmetry is discovered waiting as vapour cools to water then cools to ice.
But, anyway I have come across the internalist argument in a different context.
Please don't take offence but Smolin takes perhaps the wrong part of biology. The focus should be on theories of development and self-organisation rather than theories of evolution and selection. And Nielsen is more in the development camp I feel.
|Mar20-09, 06:04 AM||#56|
Chibeni, S. S.: 20004b, ‘Ontic vagueness in microphysics’, Sorites, n. 15 (December 2004), 29-41.
French, S & Krause, D  'Quantum vagueness', Erkenntnis 59, pp. 97-124.
Lowe, E J  'Vague Identity and Quantum Indeterminacy', Analysis 54, pp. 110-4.
|Mar20-09, 06:11 AM||#57|
I agree symmetries are important. But it's how they are treated. (Like I noted, I choose to focuse on intrinsically "observed" symmetries, and in this picture, generaly symmetries are evolving and thus emergent.
It's this mathematical beauty trend, that I simply don't get. It's too much toyery and I find no faith in the methodology. It's not the symmetry itself that I dislike. On the contrary do I expect the symmetry to be physical, not just mathematical. And physical to me means attached to interaction processes and thus be infered from the interaction/communication process.
The phase transition analogy is decent, but that would be how an external observer describes it. The inside observer does not SEE the phase transition process, it just sees an emergent symmetry, not the mechanism behind it.
To me the principle of minimum speculation is a guiding principle. But without illusions of universal simiplicity. It's the evolution that flows according the the principle of least speculation.
I also agree with you about Smolin :) I like him, because he is one of a few physicists that reasons in a way to my liking, but that doesn't mean I like everything. I do not. But as always, take what you like and leave the rest, if that makes your own coherent soup :)
|Mar20-09, 07:07 AM||#58|
If you look at symmetry as a statement, containing information about a system. One realized that there is a massive amount of information implicit in a symmetry assumption. If you add this to the idea that information capacity is limited by energy and mass, then it's not really a stretch to see that the confidence a symmetry, seen as an acquired information, scales with the information capacity.
So the flat ideas of universal symmetries that gives us "constraints for free" lacks physical basis IMHO. The reason why this happens to work fine, so far, is related to smolins argument he made in a talk on time, and evolving laws. (available as mp3 somehwere, I saved the mp3 but forgot from which talk it came). the difference is thte inside vs outside observer. Closed subsystems vs open systems.
Edit: This is almost like the "spherical cow" metaphor. Who has not seen the typical physicists abstraction: consider a closed system, with initial conditions, ...
Now, all premises must have resulted from experience, or communicatin processes. One might certainly question, how does the process look like, whereby you conclude tht a system is closed. And is the confidence in that conclusion infinite? (It's certainly not.) So closedness as it, either it's closed or itns not, ins't even a valid premised. I think there is no physical process whereby you can arrive at that premise.
You can THINK that the system is closed, and act accordingly. This we do all the time. But this is something different. It means that the action should reflect this uncertainty, and not run into hard inconsistencies if the premises were wrong. Instead it should respond promptly to feedback that are in contradiction to the prior premise, revise and evolve. The ridigly constructed models, in the past spirit rarely allow such actions. Instead it would be considered and inconsistency and run into a HALT. I have yet to see nature run into a HALT.
|Mar20-09, 10:56 AM||#59|
"The problem of time arises because the metric is distinct from matter fields. In this essay we argue that it is this split between geometry and matter that is to blame for the problem of time together with a number of other problems."
As he argued previously, matter and geometry must emerget together. Their separation is artifical, and this artifical split is the root of several problems. I personally fully agree with this.
The point where I am not sure what he means is this
"What then is the nature of time that we are proposing? In internal relativity time appears in two different ways. The first notion of time would be completely familiar to a Newtonian physicist. This time is the background time of the theory. The second notion of time would be less familiar to a Newtonian physicist. It arises because the presence of a background time does not imply that an observer has access to it. Rather, the behavior of matter determines what the observers will measure. As we have seen this means that the internal time as it is measured by an observers differs from the background time."
The fact that he acknowledges the importance of what inside observers measures is good, and the most important thing. But I have a feeling that he misses what I think is a point. What worries me is that he intendts to use an nonaccessible background structure, to explain internal relations. That is somehow in despite of his great ambitions dangerously close to the standard view (although he reformulates it), so I wonder if he will solve anything by this. But it could be that I misunderstand him there.
He writes that matter determines what the observers will measure, and I agree, though I think of it as matter somehow is the observer, or makes up the observer.
Thus it is completely clear, that never ever will there be an observer, to observer empty space. Because the mere fact that there is an observer, suggest it's not empty. This is why I think the the "pure gravity" approaches are doomed to not possibly be consistent as a proper measurement theory.
I rather think of time, as exisitin only within an observer history. Even though he also says that what is important is the observed time and space, I do not think or like the idea that it has to be expressed in terms of an "inaccessible" external structure. Not just for esthetical reasons, but because this very image also needs a physical basis.
The relation between the inside views, is again, only speakable from an inside view. Correlation between different clocks are then just emergent. Maybe this is what Dreyer mans with "not accesible external time", as in a non accesible emergent symmetry. If so we are quite close.
I'm excited to see any of Dreyers future papers. I think his ideas are interesting. The best of the essays I've read, but I haven't gotten around to read all unforunately.
|Mar21-09, 08:36 AM||#60|
From my perspective, the key issue is how information is physically defined / measured / communicated. We know that the world does in fact do this, because of course we all actually experience a tremendous amount of information in our physical environment. But physics has not traditionally explored how a self-communicating system might work -- i.e. provide ways to define and communicate every one of its own elements in terms of other measurable elements.
If we knew how to describe the world this way, as a self-defining communications system, then perhaps we could envision the original universe as something like a quantum vacuum, where anything at all can and does happen -- but in such a lawless and structureless environment there would be no way for anything that happens to make a difference to anything else. So in effect there is nothing, all events remain merely "virtual."
But we could imagine that within this chaos there happen to be any number of different networks of interlinked events... and that among these could be a network that happens to be able to define and communicate something, internally. And then that minimal shared definition might be the basis for a sub-set of that network of events, that could define more complex and specific information within the framework established by the first.
I don't know whether this will be at all evocative to you -- I hoped to say more, but my son just arrived for a visit unexpectedly and my morning plans must change. Anyway, talk about hand-waving!...
But this relates to the question of symmetries in the following way. A symmetry basically means, we can define X (say the circumference of a circle) without needed to specify Y (any specific point on the circle). So wherever there is a symmetry, it's pointing to one type of information being potentially more fundamental than another, i.e. needing less of the structure of the physical world to be meaningfully definable and communicable.
So if the world evolved through a sequence of levels -- i.e. networks of events capable of defining more and more information, given the informational structure established by lower levels -- then that would manifest itself in a highly evolved structure containing many different kinds of symmetry.
I have my own prejudices about "self-organization" vs "evolution" in biology -- but will have to wait. Oh yes, and this thread is about time in physics! Will get back to that later too.
Thanks -- Conrad
|Mar21-09, 05:08 PM||#61|
"If we are to proceed in a logical and scientific manner, we must, in order to account for the whole universe, suppose an initial condition in which the whole universe was non-existent, and therefore a state of absolute nothing."
"But this is not the nothing of negation. . . . The nothing of negation is the nothing of death, which comes second to, or after, everything. But this pure zero is the nothing of not having been born. There is no individual thing, no compulsion, outward nor inward, no law. It is the germinal nothing, in which the whole universe is involved or foreshadowed. As such, it is absolutely undefined and unlimited possibility -- boundless possibility. There is no compulsion and no law. It is boundless freedom.
"Now the question arises, what necessarily resulted from that state of things? But the only sane answer is that where freedom was boundless nothing in particular necessarily resulted. I say that nothing necessarily resulted from the Nothing of boundless freedom. That is, nothing according to deductive logic. But such is not the logic of freedom or possibility. The logic of freedom, or potentiality, is that it shall annul itself. For if it does not annul itself, it remains a completely idle and do-nothing potentiality; and a completely idle potentiality is annulled by its complete idleness. (CP 6.215-219)
"I do not mean that potentiality immediately results in actuality. Mediately perhaps it does; but what immediately resulted was that unbounded potentiality became potentiality of this or that sort -- that is, of some quality. Thus the zero of bare possibility, by evolutionary logic, leapt into the unit of some quality. (CP 6.220)
"The evolutionary process is, therefore, not a mere evolution of the existing universe, but rather a process by which the very Platonic forms themselves have become or are becoming developed. (CP 6.194)"
"[W]e must not assume that the qualities arose separate and came into relation afterward. It was just the reverse. The general indefinite potentiality became limited and heterogeneous. (CP 6.199) The evolution of forms begins or, at any rate, has for an early stage of it, a vague potentiality; and that either is or is followed by a continuum of forms having a multitude of dimensions too great for the individual dimensions to be distinct. It must be by a contraction of the vagueness of that potentiality of everything in general, but of nothing in particular, that the world of forms comes about. (CP 6.196)
"Out of the womb of indeterminacy we must say that there would have come something, by the principle of Firstness, which we may call a flash. Then by the principle of habit there would have been a second flash. Though time would not yet have been, this second flash was in some sense after the first, because resulting from it. Then there would have come other successions ever more and more closely connected, the habits and the tendency to take them ever strengthening themselves, until the events would have been bound together into something like a continuous flow. (CP 1.412)
|Mar22-09, 09:46 PM||#62|
We should haul the discourse back around to everyday physics but before doing that, one more essay on What is Time, and this time on Youtube:
Here's a longer version with additional detail:
|Mar31-09, 01:45 PM||#63|
Marcus, where could I best initiate a discussion of concepts presented in these papers? For example, the argument that time is a result of motion...it seems to me that the idea of motion already includes time, and leads to a circular argument when motion is used to define time.
And ephemeral time. Instead of using a collection of motions of stellar objects to fix time, why not simply use the furthest observable object as a fixed direction? We can now see objects so distant that they are for all practical measurable purposes constant. So the length of a day relative to that fixed direction is a constant, and also fixes sidereal time, since such a distant object could be used to make a direct correlation between sidereal and diurnal time.
I don't have anyone to talk to about these things and discussion is often the key to understanding.....
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