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A Atemporal Universe

  1. Oct 23, 2017 #1
    Some theorists have put forth the idea of an atemporal universe - ie. a universe without time - claiming that time is an illusion or abstraction created as a placeholder for what is really entropy.

    https://phys.org/news/2011-04-scientists-spacetime-dimension.html

    So they're claiming that there's no need to have a time dimension along which we all march forward, when we can simply chalk it all up to entropy. Rather than simply re-naming the Time axis/dimension to an Entropy axis/dimension, they assert that the Time axis/dimension was never really an axis/dimension to begin with, pointing out that it's not really possible to travel along this so-called axis/dimension - ie. we can't travel in time to the past, nor can we travel in time to the future. Their case is that progression of time is really governed/affixed by progression of entropy, and that time is just a numerical index/order of change in the universe.

    As I find this idea to be very appealing - it seems to simplify things, a la Occam's Razor - I'd then like to discuss the legitimacy of this idea. I'd also like to further ask if it's possible that Quantum phenomena/effects are at the root of driving Entropy increase in our universe, and are therefore the root cause of what we call "Time".
     
  2. jcsd
  3. Oct 26, 2017 #2

    Fra

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    Read this one: https://www.amazon.com/Time-Reborn-Crisis-Physics-Universe/dp/0544245598, its a nontechnical easy to read book.

    First part of the book argues for the "timelessness", and the next part argues why it's a fallacy.

    /Fredrik
     
  4. Oct 27, 2017 #3
    When I was a teenager I imagined a simple 1bit digital circuit with a data line in and out, and a clock signal. Without a memory unit (ie a flipflop) the circuit can't detect that the inputs are changing and thus has no concept of time.

    Adding a memory unit allows it to detect the changes and thus ascribe a passage of time (the clock signal). However the memory unit necessarily increases the entropy of the system when it overwrites the old state, so the curcuits notion of time would always be linked to increasing entropy.

    Maybe just a silly idea but this thread reminded me of it.
     
  5. Oct 27, 2017 #4
    Pop-sci article dumbed it so much that I can't actually understand what model do they propose. And there is no link to the actual paper.
     
  6. Oct 30, 2017 #5

    ohwilleke

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    Given that there are many observable quantities that are very high precision functions of time (Lorentz transforms, decay rates, speed of light, etc.) which hold without regard to local entropy, I have to think that an atemporal universe makes very little sense.
     
  7. Oct 31, 2017 #6
    Why can't we re-derive or re-define these same things with respect to entropy? 2nd Law says that any natural process occurs with an increase in entropy.
     
  8. Oct 31, 2017 #7

    Demystifier

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    That's quite similar to my paper https://arxiv.org/abs/gr-qc/0403121
     
  9. Oct 31, 2017 #8

    Demystifier

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    To avoid reading of the whole book, can you briefly explain why it is a fallacy?
     
  10. Oct 31, 2017 #9

    ohwilleke

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    The second law only gives you a direction, it doesn't say that entropy increases at the same rate everywhere. The RATE at which entropy increases varies considerably from place to place, unlike time.
     
  11. Nov 2, 2017 #10

    Fra

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    I am travelling atm so i will try to give a quick incomplete summary...

    ** Background
    First one should understand that smolins book is written with the quest for a cosmological theory in mind (QG) but i would like to add that the reasoning in the book is relevant also for looking for and measurement theoey formulated for interacting inside observers. It just happens to be that there are parallells between a cosmological theory of from the perspective of science of earth and and inside inference from the point of view of the first subatomica observers(particles) soon after big bang.

    **Fallacy
    The fallacy is to extrapolate the "newtonian schema" to the entire universe and to cosmological models.

    **Explanations
    The "newtonian schema" is the paradigm that processes in the universe that are limited in space and duration can be well described by timeless immutable deterministic laws that operate in a timeless state space on given initial conditions. This leads to the idea that the future follows logically from the past, and thus is timeless because once initial conditions are given.Time appears simply a parameterisation of the history lacksing physical basis. The past together with the laws encode the same information as the future. This is encoded by fixed mathematical laws operating on timeless structures. This is also related to the "unreasonable effectiveness of mathematics" as also touched in the book.

    Note that pretty much all modern physics from newtons until today fall into this category and this is our heritage. What is important to see is that this schema is successful precisely because it is limited. It is successful precisely because we formulate our understanding from repeating prepare experiments many times. It is thus expected from the inference perspective that we encode this as laws that are the same on each repeat (timeless) and operating on a fixed state space. Lets call this an external inference as opposed to inside inference below.

    Smolin argues at length(almost too lengthy) why it is fallacious reasoning to apply these scheme to cosmological theories. Some core reasons are that the inferential scheme of science that we can prepare and repeat "experiments" in order to extract the behaviour of subsystems fundamentally fails for cosmological theories. Ie the very inferential scheme of science simply does not apply to this scale. Ignoring this leads to pathological interpretations of multiple universes or landscape problems.

    The lesson is that we need a new way of understanding inside inferences. And that is the context of evolution. So instead of eternal immutable laws, Smolin envisions evolving law in cosmological time.

    But note that this does not contradict SR or GR. They should be emergeny in their appropriate domains of validity.

    A final satisfactoty solution is not presented in the book, but its purpose is to encourage a new way of thinking. One first impression you may think smolin is nuts but then i would say you havent understood it at depth and maybe havent gotten the hunch of the alternative paradigm.

    Smolin does not talk about "inside inferences" though. That is my angle to all this that gives another twist to a possible solution to the metala dilemma which is the problem that appears in an evolutionary model without fixed rules. But thats much beyond the brief explanation here.

    Btw there are two versions of the book. Om more wide audience and one more narrow audience.

    /Fredrik
     
  12. Nov 2, 2017 #11
    But the rate of time varies from one velocity frame to another. You're on Earth, I'm on a spaceship moving at some very high velocity relative to you. Which one of us is experiencing "the real rate of time"?

    Back in the days when you and I were growing up in the same village/town, then maybe this "time" thing was a good idea back then, and helped us to keep track of things better.
    But in the age of spaceflight, when we can be separated by vast distances and be in completely different velocity frames from each other, then is this "time" thing so advantageous anymore?

    So you can raise the issue of differing entropy frames, but I can raise the issue of different velocity frames (and thus differing rates of time).

    So it doesn't seem like time continues to hold great advantages in consistency over entropy, any longer.
     
  13. Nov 2, 2017 #12

    ohwilleke

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    The problem is that the difference in passage of time due to velocity frames is unrelated to the difference in the entropy rates. If the passage of time were a function of entropy, then entropy change rates and not velocity frames would govern the rate at which time passes.
     
  14. Nov 3, 2017 #13

    But that's because things have been defined that way. We could have also defined them with phlogiston too, but it doesn't mean that phlogiston is some natural inherently superior term of reference.

    How are you claiming to measure velocity and time directly? What you seem to be measuring is the entropy change on a physical system (ie. a clock) and then calling that "time".
    So if you're going to do that, then why not just use that entropy change as a standard reference/benchmark through which to define all change in terms of entropy rather than time?
     
  15. Nov 5, 2017 #14
    Fra. I read this book when it first came out in 2014 but forgot about it mostly now. What did you mean "The reason why smolin writes so lenghty a out this, is to get the reader first on the same page, before he presents the crazy idea." What crazy idea of Smolin were you talking about?
     
  16. Nov 5, 2017 #15

    ohwilleke

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    Generally speaking, clocks are not measuring entropy change. Entropy, time, and velocity are all well defined quantities in physics.
     
  17. Nov 6, 2017 #16

    Fra

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    The crazy idea is that the laws of physics may not be an eternal and timeless logical constraint upon nature but a result of evolution. Note that evolution of law here does NOT man the law Dynamically evolves as per a metlaw. It means to understand it in the darwinian sense.

    Smolin presents a specific idea o CNS where new universes form in black holes during which laws mutate. This ia because there is no sign so far that laws mutatw during expansion of the universe.

    HOW they mutate and what is the "dna" of physical law he does not say. Thata taking this to the next unexplored level.

    Also see post #10
    /Fredrik
     
  18. Nov 6, 2017 #17
    Oh. I remembered. Can you please give 5 examples of Smolin universes with different laws? How does it differ to the superstring landscape with different laws of physics? Our life is said to require very fine tuning.. but what are the ranges of the parameters values where there were different laws and still organisms could exist? Any paper that explore the parameters ranges and how it affects the size of atoms, etc. maybe even a software where you can adjust the parameters and see what happens to the molecules?
     
  19. Nov 6, 2017 #18
    Btw.. What are the candidates for "dna" of physical law? And what standard language or jargons physicists use for this term?
     
  20. Nov 6, 2017 #19

    Fra

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    There are some old threads on this, check

    https://www.physicsforums.com/threads/smolin-guesses-the-dna-of-physical-law.223450/

    However, i would say there is no standard jargon on this or no "standard" at all for that matter. This is a very non-mainstream idea.
    Also my own views are one thing but there is no one working on exactly that that has published anything, so i cant talk about that. But smolin well sets out the directionm which is a good start for most. if you are trying to understand what the standard thinking in on this, you will see there is none. Most probably think this is nonsense.

    I think you need to formulate the problem with current theories on your own first, befeore you can possible appreciate the ideas.

    /Fredrik
     
  21. Nov 6, 2017 #20
    The nonsense is thinking the universe is so simple. Even the iPhone internal components are already so complicated.. what more the universe with 200 billion galaxies once fitting into a grain of sand.. therefore nature and physical law should be more complicated than even Smolin imagined. And about the dna of physical laws. They should have their own dynamics and patterns that informs them.... isn't it. It's common sense. And it's also common sense and likely that these physical laws can be altered not just in cosmological time but inside the lab... with the right tool. You can't fix or update the iphone with wrong tools such gloves or rocks. So in physics sometimes we are lost in common sense.
     
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