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Smolin rebuts Carroll-try to explain the laws of physics

  1. Nov 29, 2007 #1

    marcus

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    Smolin rebuts Carroll--try to explain the laws of physics

    Like the Tegmark Math Universe thread the topic here is properly Philosophy of Science with input from physics. If TMU thread gets moved to Philosophy forum then this thread certainly should too.

    the issue is whether one should try to explain the laws of physics (why they are what we find them to be)

    Edge had this discussion starting from a NYT Op-Ed by Paul Davies that I didn't think was very interesting. The interesting part came out in the COMMENTS that Edge elicited.

    Here are the comments.
    http://www.edge.org/discourse/science_faith.html
    They are by 9 people Jerry Coyne, Nathan Myhrvold, Lawrence Krauss, Scott Atran, Sean Carroll, Jeremy Bernstein, PZ Myers, Lee Smolin, John Horgan

    Here is the original Davies op-ed piece "Taking Science on Faith" in case anyone is curious:
    http://www.edge.org/3rd_culture/davies07/davies07_index.html

    What I liked is that Carroll said we should not try to explain the laws of physics, and Smolin contradicted him in an interesting way. I'll get some quotes.

    Here's a sample of what Carroll said
    ==quote==
    The final possibility, which seems to be the right one, is: that's just how things are. There is a chain of explanations concerning things that happen in the universe, which ultimately reaches to the fundamental laws of nature and stops. This is a simple hypothesis that fits all the data; until it stops being consistent with what we know about the universe, the burden of proof is on any alternative idea for why the laws take the form they do.

    But there is a deep-seated human urge to think otherwise. We want to believe that the universe has a purpose, just as we want to believe that our next lottery ticket will hit. Ever since ancient philosophers contemplated the cosmos, humans have sought teleological explanations for the apparently random activities all around them. There is a strong temptation to approach the universe with a demand that it make sense of itself and of our lives, rather than simply accepting it for what it is.

    Part of the job of being a good scientist is to overcome that temptation. "The idea that the laws exist reasonlessly is deeply anti-rational" is a deeply anti-rational statement. The laws exist however they exist, and it's our job to figure that out, not to insist ahead of time that nature's innermost workings conform to our predilections, or provide us with succor in the face of an unfeeling cosmos.

    Paul Davies argues that "the laws should have an explanation from within the universe," but admits that "the specifics of that explanation are a matter for future research." This is reminiscent of Wolfgang Pauli's postcard to George Gamow, featuring an empty rectangle: "This is to show I can paint like Titian. Only technical details are missing." The reason why it's hard to find an explanation for the laws of physics within the universe is that the concept makes no sense...
    ==endquote==

    I think some readers can probably see this contains a number of erroneous statements protected by a little strawman rhetoric. Science has barriers and they sometimes shift. The chain of explanation never really terminates. It's always legitimate to push further. Whatever laws we have, that have been well-tested and found reliable, it is always fair to say "these laws should have an explanation from within the universe," and to look for it.

    In fact this quest has succeeded in the past. Smolin gives an example of where an explanation was found for a law of nature, and we can think of others. It's NORMAL to look for and to find deeper explanations of already established pattern.

    Mathematics is a human language, one that could have evolved differently. Surely it is a rather good language, but its specifics are largely accidents of human history. The human brain is admirable in its ability to understand and explain, but it too is an accident of evolution. Mathematical laws empirical models and explanations are human artifacts: when we find a deeper explanation for an established law we are only improving on our own work.

    The odd thing was that Smolin was the only one of the 9 commentors who made this point! He didn't say what I just said, it was somewhat different. I'll get a quote.

    BTW I think the thing is red is flawed. The opposite statement also fits the data equally well (that the chain of explanation continues indefinitely). And this agrees with our everyday experience of explanations. Also the red statement involves something that is not well-defined, like referring to "The King of France". What does "the fundamental laws of nature" mean? Have you ever seen one? It would necessarily be a human artifact expressed in some human language, this is what laws are, probably some form of mathematics developed in some future century---but can you really treat that as a clear idea suitable for a logical statement about the termination of a sequence?
     
    Last edited: Nov 29, 2007
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  3. Nov 29, 2007 #2

    marcus

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    Here's a sample of Smolin's comment
    ==quote==
    Davies point is that if we just accept the laws and initial conditions of the whole universe as just given, with no further explanation, then we are reducing science to faith in the unexplained. He is right about this, but he doesn't emphasize that these questions are avoided in most domains of science, where we study isolated systems in a larger universe. In these cases we can cleanly separate regularities into laws and initial conditions.This gives an operational meaning to the notion of fixed laws. It is only when we extend our reach to the universe as a whole, that the distinction between laws and initial conditions becomes problematic. For example, there are observations, such as wiggles in the CMB spectrum, that can be explained either by modifying laws or modifying initial conditions and, since there is only one instance of the universe, there is no way to determine which is correct.

    This suggests, however, the need for a better notion of law, applicable on a cosmological scale, not for a surrender to religion or metaphysics.

    Indeed, there are reasons to worry that contemporary cosmological theory has wandered from the domain of science. Reliance on infinite and eternal ensembles of universes, and use of the anthropic principle, popular as they have been in the recent literature, have not led to a single falsifiable prediction. There is a real danger of unjustified belief in putative unified theories that cannot be experimentally tested.

    But these are not the only possible responses to the questions of "Why these laws?" and "Why these initial conditions?". They are only the result of approaches to them that fail to critically ask what notion of law is appropriate for doing science on a cosmological scale. In fact there are approaches to these questions that, if they succeed, will bring progress to science, in the conventional sense that it will lead to new predictions which are falsifiable or verifiable by doable experiments

    There is a healthy skepticism about the role of philosophy in science, but when it comes to this issue of "Why these laws?" there is wisdom to be gained from studying philosophers who anticipated that science would reach the point of asking this question. Leibniz postulated two principles to address it, which are his "Principle of sufficient reason" the "Principle of the identify of the indiscernible." The first posits that we live in a universe in which every question of the form of "Why these laws?" or "Why these initial conditions?" has a rational answer. The second implies that there are no symmetries in the fundamental laws of nature. These principles are the underpinnings of the relational approach to space and time which culminated in general relativity.

    Indeed, before relativity there was believed to be a law of nature of the form, "The geometry of space is three dimensional Euclidean geometry." People, for example, Kant, try to explain, "Why this law?" But in fact there was a perfectly rational answer, on which much further progress has been based. In general relativity the geometry of space is not determined by a law, it is a contingent and changing fact. The geometry at present can be understood to be the result of lawful evolution from past conditions. This is an example of how a deeper law can be discovered which moves an apparently eternal law to the status of contingent and fully explainable.This shows that the idea of a universe determining its own properties by dynamical evolution is not senseless, as Carroll suggests. It has been fully realized in general relativity and could be so again.


    ==endquote==
     
  4. Nov 29, 2007 #3

    ZapperZ

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    Don't you think this is more suited for Philosophy rather than Physics?

    Zz.
     
  5. Nov 29, 2007 #4

    Fra

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    I personally think it's philosophy of physics, which in turn belongs to foundations of physics and science and perhaps the comparation with religion was not very interesting but it does raise some points that I think is highly relevant to the foundations of science. In particular Smolin's comments, which I personally think fits well in "beyond the standard model"?

    I think it will too.

    At least the way I interpreted some of Paul's words "But until science comes up with a testable theory of the laws of the universe..." I interpret as a challange to actually analyse the scientific method itself, because IMO it's not as "foolproof" as some people seem to see it. But I do not see why we can't analyse the scientific method itself? the falsification immediately leads us to probability theory because the "probability" that our theory is right must be quantified, and that must include quantifying the evidence/information? But like we know the probability itself is only estimated by it's relative frequency. so there is still a foundational uncertainty. it's not foolproof. Many people think this nitty gritty stuff is irrelevant philosophy. But is that really so? Maybe once that we have relaxed our background, it becomes EASIER to find a solution?

    Maybe I am naive but the natural route I see is a natural combination of the relational philosophy of GR AND the information abstracted concept that physics concerns what is observable from quantum mechanics. Such a relational information theory would of course be even more complex than the sum of them both, but for me it seems like a natural extension and I even think there is a somewhat natural way to unite them. The inconsistencies in the underlying foundations has long been ignored or blamed to be meaningless "philosophical questions".

    Something that seems clear from discussions is that many physicists simply doesn't see any reasonable resolution to the foundational questions, therefore they soundly aren't even trying. This is logical behaviour. But preaching to others that what I can't see is a waste of time speaks for itself.

    There is one specific point where I think Paul hit the nail about "faith". That's about unitarity. The idea that our _subjectively estimated probabilities_ are always normalised in time. This is to say that we have at the initial conditions, determined completely all possible outcomes and there is no way that something can happen that doesn't fit into this view. Now if that's not faith, what is it? Sure it's faith on GOOD grounds, but neverthelss it's an expectation, not a law carved in stone.

    Because the whole concept of probability means the probability space is given. Then unitarity follows by definition. But if the probability space itself is uncertain - and there are good grounds for this, because the probabiltiy space is not trivially measurable unless you have the information smeared out over the age of the universe and have infinite storage capacity. Unless you are one of those divine imaginary birds who can know and see and calculate everything without limits of physical storage and processing.

    There are alot of things that are far from proved, that are at least rarely questioned. Many papers seems to still build on alot of estimates, as if they were solid, and they work out the implications into unproven domains.

    Wouldn't pointing out (and acknowledging) and analysing the unavoidably WEAK points of our scientfic models and formalisms help us improving it?

    /Fredrik
     
  6. Nov 29, 2007 #5

    Astronuc

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    I believe that marcus made such a comment in the OP, although it was conditional (i.e. wrt TMU thread).

    marcus, what is incorrect about this?

    Take GL's ESTOE, assuming it is correct. It, like any TOE, explains what and how, i.e. it explains relationships, but it certainly doesn't explain why. No model or theory of physics can explain why. The laws effectively go as far as "If this, then that", or conversely "if that, then this" but not why "this or that are what they are".

    The bottom line this thread seems to involve epistemological and philosophical discussions.
     
  7. Nov 29, 2007 #6

    George Jones

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    Suppose experiments at the LHC fit Lisi's theory, and they fit no other theory. Maybe 50 years from now, a new experiment will require a new theory. As marcus says, the chain could be never-ending. This fits the data as well as Carroll's hypothesis, if not better.
     
  8. Nov 29, 2007 #7

    Fra

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    I don't know how you guys see it, but aren't we (this is my impression) here trivializing the scientific process itself? Perhaps the scientific process itself applied to an arbitrary system, is nothing but the very physical processes of interacting with the environment? Could it sort of be the same thing? Would such an analogy be a far stretch to most people?

    In the light of the philosophy expressed well by Bohr

    "It is wrong to think that the task of physics is to find out how nature is. Physics concerns what we can say about nature."

    How about, if we in this spirit instead analyse why we come to believe that the laws of nature are the way they are? Ie. lets try to quantify and formalise the obvious that everybody accepts anyway! the scientific process! Exactly how does the retained history of observations of an observer induce it's expectations? And how does the observers expectations affect his actions, and how does the behaviour of the environment - remodel - the observers view? and finally stabilise certain things as "laws" - laws induced from processing the history of data - constrained by the observers limits - this is nothing but the scientific method we all cherish, but still I see a bit of a schitzophrenic attitude towards this?

    Does this simple idea appear twisted, too difficult to turn into a formalism, or simply off the map to you? Maybe it's me, but could it be more beautiful and natural if we could pull this off?

    /Fredrik
     
  9. Nov 29, 2007 #8

    Astronuc

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    I provided a terse post, rather address each statement. I was just curious about the red statement and marcus's comment about it being flawed.

    I don't think we are trivializing the scientific process. Certainly, I am not. We're not discussing the process, but rather, what are the expectations of those engaged in the process. Is the expectation of physics (what used to be 'natural philosophy') to simply describe all the relationships of things in the universe, or is the ultimate goal to discover the why, the 'purpose' of the universe?

    Digressing somewhat, what is the expectation with respect to the 'laws' of nature? Should we necessarily expect symmetry? If so, should that symmetry be 'universal'.

    I'm quite comfortable that things are the way they are? Likely I will not live beyond another 50 years, if that.

    I would hope Lisi's theory is compatible with known laws (relationships - EM, weak, strong - EW . . . gravity).

    Laws are adjusted/revised/refined as we learn more, or discover something new that we didn't know.

    We can only know what we can observe and test. Beyond that is speculation/extrapolation (with some reasonable basis), and beyond that is faith (speculation without a reasonable basis, or in some cases, in spite of evidence to the contrary).

    I'll need to think more about this topic, and I think we need to be careful with semantics.
     
    Last edited: Nov 29, 2007
  10. Nov 29, 2007 #9

    jal

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    What made our universe what it is?
    http://www.edge.org/discourse/science_faith.html
    On "TAKING SCIENCE ON FAITH" By Paul C. Davies
    Jerry Coyne, Nathan Myhrvold, Lawrence Krauss, Scott Atran, Sean Carroll, Jeremy Bernstein, PZ Myers, Lee Smolin, John Horgan
    I agree with Astronuc.
    Unless this discussion is willing to look deeper into individual “laws” then it will not be possible to get any “… predictions testable by real experiments”.

    You should be asking questions like:
    1. Is there a minimum length? What are the implications? What kind of universe does it create? Is it our universe?
    2. What mechanism makes waves? Why is there waves? Can you have a universe without waves?
    3. What makes the geometry that we have? 90 degrees? 60 degrees? Triality? Can you have any other geometry? Will it be our universe?
    4. Can you have our universe without our symmetry? What cause that symmetry?

    ------------
    jal
     
  11. Nov 29, 2007 #10
    Please remember that this discussion does not occur in a vacuum. We can talk big and sound smart, impress each other with our erudition, gain all sorts of points and kudos, but at some time our talk goes beyond us. It gets out to the general public, and ends up interpreted by people who don't have any knowledge of the fine points we stick to each other.

    This morning in the doctor office I heard two farmers discussing science and religion. They both agreed that science is no better than religion, and finally is just a matter of opinion and preference. The fact that they were waiting for blood tests in a scientific regime that has extended and improved their lives did not inhibit them from equating scientific knowledge with spiritual faith. Yet I can tell you for a certainty that neither of these practical men would consider being slapped on the forehead by a faith healer to be "just as good" as their blood tests being interpreted by a scientifically trained physician. They would not pray for their tractor to be protected from demons, or for their broken harrow to undergo a spontaneous conversion and become whole again.

    How is it that these good men can be so confused about the value of science? They have seen the high priests of science arguing in the public media. They have seen their doctors prescribe medications that later are recalled. They see conflicting claims by scientists, pseudo-scientists, and outright frauds, and they can no longer either evaluate the claims or trust the claimants. Surely we can do better than this.

    I don't think anyone here means to pull the rug out from under scientific accomplishments, but be careful. Funding for the next generation of experimentalists depends on the "faith" these good farmers and mechanics have in the sciences. Are they going to "believe" in the benefits of science enough to be willing to send their hard scrabble tax dollars into outer space, or are they going to send their tithe to the missionaries who are bringing bibles to the starving people of Darfur instead? How should they know the difference?

    We can and must continually examine our facts and our methods, just as the mechanic checks the oil level and the farmer makes sure the tines on the harrow are sound. But when we talk about the unknowability of the ultimate meaning of everything, we better be sure we are not sending the public message that scientific method and the search for hard factual information is useless.

    It may very well be that the final answer will continually elude us, but the benefit of looking for answers closer at hand is a long way from being exhausted. And part of the search for benefits at hand is to look up and out and wonder what is beyond the next horizon. It may be categorically impossible to find out why everything is the way it is. It is none-the-less vital to wonder why, and to struggle to squeeze answers out of the cold, insensate universe.
     
  12. Nov 29, 2007 #11

    George Jones

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    Well, that goes without saying. By "no other theory," I meant no other theory that purports to the ultimate in reductionism, i.e, these hypothetical LHC data falsify all other theories that purport to be the ultimate in reductionism.

    I think Carroll means there is a theory that is the ultimate in reductionism, and once we find this theory, we will, in principle and in practice, never make a measurement that falsifies this theory. The chain ends. Once we find this theory, no new (reductionist's) theory will ever be required. Maybe I misunderstand Carroll's statement.

    In my opinion, the data equally supports a scenario in which no such ultimate theory in reductionism exits, i.e., the chain never ends. Think Aristotle --> Galileo/Newton --> Einstein/Heisenberg/Schrodinger/Dirac --> ? --> ?? --> ...

    I also hold the opinion that we will never know which scenario is true.
     
    Last edited: Nov 29, 2007
  13. Nov 29, 2007 #12

    ZapperZ

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    I think my revival of this thread today on A&CG forum is extremely timely. :)

    Zz.
     
  14. Nov 29, 2007 #13

    Astronuc

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    Yes! Very appropriate and timely. Thanks, Zz!

    I think everyone who wishes to comment here ought to read Quinn's article. We need to choose our words carefully - i.e. we need to be precise.

    I need to read the first two posts more carefully, and I need to carefully read the original articles - but when I have more time.
     
  15. Nov 29, 2007 #14

    marcus

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    Topic is an excellent op-ed piece from Physics Today calling for the careful and conscious use of language. I'll put some more detail on it in case people miss going to the link in Zz's thread.
    http://www.physicstoday.org/vol-60/iss-1/8_1.html

    Belief and knowledge—a plea about language
    Helen Quinn
    January 2007 issue of Physics Today

    "Helen Quinn is a theoretical particle physicist at SLAC and was the president of the American Physical Society in 2004. She has had a strong interest and involvement in science education and public understanding of science throughout her career."
     
  16. Nov 29, 2007 #15

    Fra

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    I see your distinction, but my personal opinion at least, is that the process of learning, and what is learned is somewhat inseparable and entangled. This was my point.

    IMO, the answer "why x", lies in the analysis of the process of the induction of x. It may seem silly but I think that given the right abstractions this could be a powerful key.

    So discussing the outcome of the process without analysing the process itself doesn't quite make sense to me at least, but that's just my personal unimportant opinon.

    /Fredrik
     
  17. Nov 29, 2007 #16

    marcus

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    I just got in, still having coffee. Somebody asked why I thought that sentence in red was flawed, and I should answer. But then George wrote this, which answers and I subscribe to.

    that is what I want to emphasize. the data does not distinguish. it equally supports a neverending possibility of explanation (if we just keep pushing) and a terminating sequence.

    what do you say if the data equally supports a proposition AND the contrary proposition?
    You can't claim the data supports either. But Carroll does claim (he says it supports him and the burden is on the other guy---just rhetoric). So Carroll is wrong.

    but I had something more to say going a little bit beyond what George said, that may be more personal and controversial. I think that a final theory is a FANTASY. Because theories are human artifacts.

    So if a theory has not been articulated IT DOES NOT EXIST. It is not like theories exist in Nature the way a fossil bone of a dinosaur exists inside a rock and you just have to crack open and find it. The theory actually is not there until some human offers it for testing.

    theories are statements in some human language which we never know if they are true or how generally they apply. they get well-established if they pass lots of tests.

    I hope some day we meet aliens and can find out what THEY have that is analogous to mathematics and to our mathematical theories of nature. I hope they are empiricists too (it would be very encouraging.) If they have, say, Lie groups it will be cause for great rejoicing IMHO. But we didn't have that experience yet---so i am saying that theories are human artifacts. So one of the terms in Carroll's statement is like saying the King of France, or the Gumbo of Foo-foo. It is an undefined term.
     
  18. Nov 29, 2007 #17

    Fra

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    I agree this is all good questions, but I also personally think the preferred attempt of attacking them depends on how the choice of philosophy of science, at least it does for me and I can speak for myself at least.

    Some thinking.

    1. I could not imagine answering this without also answering, what is space?

    To speculate, if the idea that the environment lives in the structure (encoding information) that definens the observer is to make sense, then the observers limited information capacity would have to limit also space because the projection of the environment is constrained by the screen where it lives. And to the observer, this is as close to reality it gets. What is going on, on this "screen" is what the observer can say about reality - in the spirit of Bohr's philosophy. So as far as I am concerned, I think that relative to an observer of finite information capacity, there has to be some kind of limit to the resolution of structures (space included).

    The other question is how different observers compare their subjective measures to arrive at the apparent objective reality?

    2. I assume with waves you mean the complex amplitude (wavefunction)? This is a problem I am currently trying to understand. I suspect that there is a solution that can be interpreted as selection of transformations that yield good datacompression. But compactifying the data into a more confident part and a less confident part, it might increase the fitness of the observer. The importance of datacompression is that unless the observers information capacity grows, it has to continously radiate off excess information... and ideally this should be the least useful information (most random I guess), or what gives best estimate info gain.

    Oddly this is exactly where I am at the moment. I found that this is probalby also the key to understand emergence of dimensions. I've been circling around this too several times and it seems to be a key.

    I haven'tseen a proper resolution ot this yet. Many approaches on consistency of the complex amplitude approach that set out to try to induce that this representation is unique is making assumptions.

    I'm currently trying to look for transformations, that transforms the memory record of the observer into an alternative record, producing an alternative history and sort of a different probability space. This spaces can then be combined and information in then can be mixed, by sharing memory. Perhaps there is an optimation problem which renders at some point the complex amplitude approach unique. That's what I think, but I haven't found it yet. If this is correct, the optimation problem could also be the generator of all structures. But the actual choice of struture that emerges is dependent on the actual date fed into it. But MAYBE, there are like, some preferred structures (maybe those we find) that does form spontaneously if you start out from a minimal starting point.

    3. Most efficient representation of data? Trying to fit the data with some other dimensionality might probably far less efficient, and thus observers can not persist with this attitude.

    /Fredrik
     
  19. Nov 30, 2007 #18

    Chronos

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    But, observables are the only meaningful measure we have of processes. Processes are relational, an abstract representation of how matter and energy interact to produce observable consequences. Mathematics proves there are many ways to obtain the quantity 1. But, math merely rules out transactions where 1 is not a possible result. Do all possible solutions have physical counterparts? Unknown.
     
  20. Nov 30, 2007 #19

    Fra

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    But can't we say at the sime time that processes is the only meaningful way we have to gain knowledge of observables?

    I've spent a decent amount of thinking on this, and at least for the moment my best personal opinion is that ontology and epistemology are sort of dual to each other. They come together. So instead of taking one side for granted and analyser the other one, I try to analyse the relation between the two because they depend on each other. That's the cleanest view I've found, but there is alot of missing details.

    I think think that some things we just don't know, but at some point I think many apparently observerd processes might be understood in terms of the most efficient process that arrives at the same result. Here I think time enters too. Efficient transformations are faster (or more likely).

    I imagine that the uncertainty of the state of our observables as well as the identity of our _set of observables_ is exactly what by means of transformations (taking place in the observers memory, creating alterantive histories) can induce "processes". The most favourable transformation will evolve that keeps the observer "fit", this is "mirror" external processes. Ie. the external processes will have mirror processes living on the projection screen defined byt the observers "set of observables", or "microstructure".

    I agree completely that this is unknown.

    But to feed the discussions, I at least see plenty of exciting possibilities here. My main point is that at least _maybe_ it's a mistake to separate the process from it's output?

    I've got a good hunch that this can be formalised in terms of a generalised probability theory, which takes algorithmic forms. But instead of "computing time" (as referring to an external time and computer), there is relational time that is defined by relative subjective probabilities.

    I guess I'm terribly navie, but I feel almost sure that this is must work. But I started revising this just a year ago, and I barely catched up with myself from the 10 year break. This is a little bit inspired by cellular automata ideas, but from what I've seen a major difference is that the "cells" in the automata are not objective, they are sujbectively induced in the on the observers screen.

    /Fredrik
     
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