Wednesday, October 6, 2010

The randomness at the heart of reality

Is reality ultimately based on randomness? How one answers this question ultimately colors one's outlook (I suggest) in deep and subtle ways. Of course, there are many ways one could approach the issue and there are ambiguities in the question itself. But I am drawn to such questions as this (as a moth to a flame?) and, since I read and think about them, I might as well write about them here from time to time.

Here, then, are a few notes about Vlatko Vedral's view of the issue ...

Vedral draws a distinction between "classical superficial randomness" (e.g. coin tosses) and "quantum fundamental randomness" (see Decoding reality (OUP, 2010), p.163). Randomness approximates to unpredictability and much in our world appears random because it is impossible to predict in practice even if in theory one could do so using the methods of classical physics (if one had all the relevant data etc.). But the quantum world is different. No prediction can be made (even in theory) of certain quantum events. Quantum theory embraces randomness, and sees some quantum phenomena as random in a fundamental sense.*

We can think of scientific theories, Vedral writes (p. 166), as computer programs "with the output being the result of whatever experiment we are trying to model. We say that our theory is powerful, if we can compress all sorts of observations into very few equations."

But any theory will be finite and will (as Gregory Chaitin first fully realized within information theory) only produce a finite set of results. "In other words, there will be many experimental outcomes that could not be compressed within the theory. And this effectively implies that they are random." (p. 167)

Is the randomness in quantum theory due to the theory's incompleteness - our lack of knowledge of a more detailed deterministic underlying theory - as some people think? Or is "randomness inherent in the Universe, and therefore ... [an essential] part of any physical description of reality? Randomness could simply be there because our description of reality is always .... finite and anything requiring more information than that would appear to be random (since our description could not predict it)." (p. 167-168)

Vedral states what he sees as a "very profound conclusion" that this view implies: "that randomness in quantum physics is far from unexpected - in fact according to this logic it is actually essential. Furthermore, it would mean that whatever theory - if any - superseded quantum physics, it would still have to contain some random features." (p. 168)

To me it matters (or seems to matter) whether or not randomness is at the heart of things. Does it matter to you?

* I have revised this passage slightly in response to a comment.

15 comments:

  1. Random? Not as I understand the word. Quantum mechanics is statistical, not purely random. Certainly at the level of atoms and molecules nature is fairly Newtonian. When I look at nature I see patterns everywhere. If QM were purely random, how could there be atomic structure? Why would one atom of hydrogen behave so very much like another?

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  2. I would surmise that the fascinating issue for you, unstated but implied, is how (or whether) an apparently systematic and orderly universe can arise from random sources. The fascinating issue for me is (since I believe the answer is yes), the possibility that "randomness" actually could be a necessary characteristic of the physical universe.

    Consider motion and time, for instance. If nothing moved, time would be impossible. So would life. The universe would be static, unchanging, completely quiet and still. This is not the condition of the universe, obviously, and that might be true because it "must" be chaotic to exist at all. If it were not for imperfections in the makeup of matter, probably the universe would be just a big solid hydrogen ball. I can easily see the point that instability of some type might be a requirement of existence.

    But randomness? Interesting this writer could use other, similar terms. Chance, chaos, and randomness are related ideas, similar but not identical. Maybe it's just this writer's diction. He seems to be speaking of chaos theory, but not using the word. I haven't read him and probably won't. But I have no trouble believing that order is, so to speak, the entropy of chaos and that is what we see when we examine the universe: an entropic process that "devolves" order from (ahem) randomness.

    Some people might be tempted to think a random foundation to nature justifies a random approach to human existence (it's meaningless; how we act doesn't really matter; ego is the only reality). "As above, so below." That same fallacy saw humans as the center of the universe when the universe was "harmonious spheres," and saw human values as "relative" when matter, space and time were seen as relative. It's a non-sequitur. Worse, it's metaphysics. LOL.

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  3. CONSVLTVS, you are right - the quantum world is not purely random, and clearly there is order in nature even at the level of atomic and molecular structures. But particles can be in two, mutually exclusive quantum states simultaneously (e.g. an electron can be in two places at once or a photon can be polarized vertically and horizontally at the same time). This superposition is a fragile state and randomness comes in - as I understand it - when information is extracted from the system and the object "chooses" (seemingly randomly) one state or the other.

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  4. GC, you have packed rather a lot into your comment and I'll take a while to digest it. My initial response is that I'm inclined to agree that randomness (or something like it) might be at the beginning or source of things as well as (or instead of) at the heart of things. (Quantum fluctuations and all that.)

    On the philosophical/psychological side, I am not really ready to commit myself. As I said, how one sees these matters may well color one's view of life to some extent, but I certainly would not want to see life as meaningless and throw all ethics out the window just because we and the universe might be here by accident!

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  5. I can think of two ways in which randomness might be relevant to us.

    One: if God exists then the universe is not random (God is no dice-thrower). But randomness is real (according to most physicists). Therefore God does not exist. Therefore we can stop worrying about theistic religion.

    Two: if determinism is true (that is, all events are governed by causal laws), then there is no randomness. But randomness is real. Therefore determinism is false. So, possibly, we do have free-will.

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  6. Alan that's a clever use of randomness. With just a bit of formalization (marshaling facts, sources, deductions) that would make a good article.

    However I shy away from arguments that make "free will" depend on how deterministic the universe is. Reason: at the macro (more organized) levels of existence, the Newtonian physics of mechanical cause and effect kicks in. If "cause and effect" is a valid construct, "determinism" in some degree is valid too. If free will is not possible in a deterministic macro world, then humans are just machines.

    To escape that conclusion, the classic answer was that either we must become "compatibilists" (an effort that has never convincingly succeeded) or else "free will" is an illusion.

    But once again, our assumption "as above, so below" actually is a fallacy. As the universe is constructed (mechanically), so is the human being; according to the classic view, we are subject only to the "laws of nature."

    The alternative is to find a way to describe "free will" as not conditional or dependent upon cause and effect. My position is that thinking is the human exception from cause and effect. Part one of that argument is posted here: http://hypermoxie.blogspot.com/2010/07/freedom-is-radical.html

    Mark I'm only saying "As above, so below" is a fallacy. And your response captures the point exactly: even if the universe is meaningless (ie, it has no inherent purpose or point), we need not conclude that human life is meaningless. "Homo sapiens is the meaning animal." We're different.

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  7. GC, it may be the embryo of an article, but I'm probably out of my depth already.

    You misread my view on freewill. My conclusion was not that we have freewill, but that it is possible that we do. Determinism can't win the debate a priori. The principle of universal law-like causation is invalid, if randomness is real.

    Whether we humans have freewill would have to be argued out on a piecemeal basis, which is what you do. The rest of what you say, I agree with.

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  8. We are all out of our respective depths I fear, Alan! (Even Vedral.) But it's good to talk about the issue and your 'embryo of an article' is wonderfully concise.

    GC, I'm glad we agree on this.

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  9. I see that Vlatko Vedral has his own website, http://www.vlatkovedral.org/.

    It links to a short and easy essay on freewill and determinism:
    http://www.qi.leeds.ac.uk/~vlatko/articles/determinism.pdf.

    His conclusion is agnostic on whether we have freewill.

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  10. Alan: My target was not your comment, but the general idea routinely expressed by philosophers that the possibility of free will depends on how deterministic the universe is. I don't know what kind of fallacy that is, but I do think it's a fallacy (similar to deriving ought from is). I didn't mean to imply you commit the fallacy. Especially since I can't precisely define it myself ... LOL

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  11. Yes, but the "fallacy" is only fallacious if they claim to demonstrate the actuality of freewill. If they merely claim to demonstrate the non-impossibility of freewill, then there is no fallacy, I think.

    (We'll stay away from the is/ought just now!)

    Mark's topic has made me appreciate better how "heretical" randomness must have seemed to physicists. To deny universal lawlike causation does seem like denying the first premise of physics. It's like a theologian wanting to carry on with theology, after converting to atheism.

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  12. By the way, when I suggested in a previous comment that we might all be out of our depth here, I meant to make a point about the nature of the topic(s), not about the quality of the input!

    Alan, thanks for the V.V. reference.

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  13. Fascinating thread.

    If the universe is "meaningless" then indeed we create meaning for it and for ourselves. Our attempt to do so, however, is pointless without...free will. GC's tour de force on "radical freedom" is reassuring, in the sense that it seems to guarantee we are not pre-destined for good or ill.

    Without choice, morality is as meaningless as the universe itself. Why strive to be good? Nihil est.

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  14. The theory stems from what is observed in data compression and should not be viewed in a macro sense. It shouldn't even be viewed in a micro sense but only in a fundamental sense. If you take any batch of information in a digital encoded form and compress that data then what you get is a more random batch of data. The more random the data is to begin with the less compressible that batch is. Essentially our information is made up of building blocks of random components . Nothing can make up the original information better than the original information itself or this composition of randomness.

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    1. I think I understand your basic point about compression of data increasing randomness insofar as, at the limit, totally random data cannot be (further) compressed. But I am unclear what you believe does or does not follow from this; or whether you are rejecting the idea of scientific theories being like computer programs with the output being a representation of the data/observations we are trying to model or 'explain'.

      It seems to me a plausible view that reality (seen in terms of information) is ultimately not compressible and so is random in a fundamental sense.

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