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    Spooky World Or Crazy Mind: Nonlocal Realism Versus Local Antirealism
    By Sascha Vongehr | May 30th 2011 11:28 PM | 16 comments | Print | E-mail | Track Comments
    About Sascha

    Dr. Sascha Vongehr [风洒沙] studied phil/math/chem/phys in Germany, obtained a BSc in theoretical physics (electro-mag) & MSc (stringtheory)...

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    Salted banana peels taste bad. This implies that non-salted banana peels taste good, right? No? Why then does local realism being wrong imply that non-local reality is true? Such is widely opined to be the only sober solution because it conserves good old reality, the scientists’ fort that is to be defended against the onslaught of irrational magic.

    However, reality with “spooky actions at a distance” is not so non-magical either – no surprise that many refuse to accept it. Nevertheless, the issue is known as “non-locality in quantum physics”, never as “non-reality in quantum physics”. This is precisely the point where we witness an old paradigm hindering progress.


    Banana peel tastes horrible lest you are an elephant – adding salt is not the problem – on the contrary. One of them has to go, the “local salt” or the “real peel”. Which one are you ready to give up? How about keeping localism and instead accepting that realism is a god of the gaps in retreat? Don’t like it? Well, how about at least not being so cock sure about it for starters?



    If you desperately cling to reality while fighting against pseudo-sciency magic, you may well end up with nothing less but “magic realism”. That’s not what you wanted.


    Modern science has disproved naïve realism: There is no locally realistic description of our world possible. We can approach this insight from different directions, for example by explaining that 'real stuff' cannot provide an acceptable fundament ‘at the bottom’. However, anybody with some interest into science and philosophy should work through one of the rigorous proofs of ‘non-locality in quantum physics’ at least once. This issue is the most important piece of philosophically relevant physics mankind has discovered; there is no excuse to be ignorant or half-hearted about it.


    The proof is one ad absurdum: One tentatively assumes that everything depends only on what is locally present in form of ‘real stuff’; that Bob’s random decisions done far away do not influence Alice’s random choice for example. A certain relation, namely Bell’s inequality, is then obviously valid, but the experimental observations clearly violate that relation.


    A lay-person-accessible yet still watertight version of the established proof introduces what is actually observed in experiments with photons and then shows via contemplating tennis balls that it is impossible to account for what is observed inside a locally realistic framework.


    Local realism cannot possibly describe the world as it reveals itself to us in the laboratory. Whatever ‘structural realism’ or ‘functional realism’ you may hold dear, whatever it is that you call “real”, it should not be based on a fundament that is locally real, where all the information necessary to determine the physical evolution right here is also present in the vicinity right here, while circumstances far away are real in the sense of determined, really being either one way or another, too.


    One of them has to go, the here or the real. Which one are you ready to give up, or which one have you given up, and has it actually helped you to understand the core of quantum theory? No? Well maybe you gave up the wrong one! What about reconsidering instead of just obnoxiously pushing the myth that supposedly nobody understands quantum mechanics just because you do not?


    Albert Einstein was a realist and believed that the only resolution of this non-locality issue could be that somehow Bob’s random choice immediately changes the hidden variables at Alice’s place or vice versa. This would imply faster than light interaction and so Einstein got his pants all in a knot about it. In 1947, Einstein wrote to Max Born that he could not believe that quantum physics is complete "because it cannot be reconciled with the idea that physics should represent a reality in time and space, free from spooky actions at a distance."


    Some find it obvious that we need to abandon localism but not realism, because somehow, realism is obviously the more sober, proper, scientific position that guards against crazy, obscure idealism. This clinging to realism blinds itself against the fact that a non-local reality is so spooky (read “spooky action at a distance”) that it is actually much less sober than keeping localism instead.


    Localism is a very successful piece of physics, while realism is the god of the gaps in awkward retreat, desperately trying to argue that it is for some reason not just comfortable but also important. Scientists keep realism plainly because they are not even aware of that they do make a choice. Realism seems so utterly obvious, it does not occur to them that they do have a choice in the first place.


    The advanced way to think about these issues is the way Hugh Everett for example started it. You may favor a description in terms of a local physics, however, what is “real” becomes relative. Relative to locally well described Alice, Bob’s decision and observation is strictly undetermined until she can observe it. Bob, the Bob that observed photon number 3729 at angle φ1 and saw it come out of exit “0”, is realized by Alice, but only by the one who measured her photon number 3729 at angle φ0 and by the one who measured at angle φ1 but saw her photon come out of exit “1”.


    Many refuse Everett relativity because they confuse it with multiple worlds interpretations (MWI) and multiverses. These are not the same. In fact, MWI are at times monstrosities of desperate realism while Everett relativity is plainly a necessary improvement in terminology that is consistent with antirealism.


    Is it not strange that scientists rather keep some mumbo-jumbo “realism” that nobody can define in any helpful way instead of keeping with something as clearly defined as localism? Does realism feel totally obvious to you? Well maybe that is the hint!


    I am not going to tell you that you should refuse realism, plainly because “realism” is anything to anybody. It is worse than “god” in that respect. I can only promise you one thing: If you do not at least update your terminology by uploading Everett relativity, you cannot understand the core of quantum physics. You must either stay with the crack-pots on the no-idea-at-all level, or reside on the popular we-don’t-thus-nobody-can level.

    Comments

    I am a reasonably intelligent person who reads many of your blogs, and yet this one was very dense to me. I hope I understand the bulk of what you are saying; but are you also saying that there are not, should not be, multiple (parallel) universes? Even if your description of reality is valid, I don't see why it would necessarily invalidate the latter hypothesis. I admit it, I am biased, hoping that there are uncountable universes out there, with every single possibility existing, overlapping, even affecting things between universes. Oh, and since I am a holder of some faith, I also believe the universes are fundamentally held together by the will of the Ultimate Being(s), from Whom we derive all of the aforementioned laws of Physics. Now if your head hasn't exploded from that... thoughts?

    vongehr
    "but are you also saying that there are not, should not be, multiple (parallel) universes?"
    No, I would never say anything like this for the reason alone that this hangs on what "exist", "universe", "parallel" and so on refer to, not so much on anything that is usefully defined for example inside of physics.
    Sorry for being overly dense maybe, but I actually thought I was quite clear: Local realism is proven wrong, so one of them must go, either local or realism. Almost all who understand the proof (I do not care about the many who do not even get the proof) agree that local is the bad guy and that the fact that the difficulties with quantum physics nevertheless remain is not due to this having been the wrong choice of bad guy but instead quantum physics being somehow fundamentally unfathomable. I actually never had these difficulties, but then who listens to somebody obviously crazy as proven by the fact that he could possibly doubt realism.
    The MWI picture is getting elegant and natural once we recognize that it is not universe splits apart (it’s always in superposition state) but observer is constantly branching. Our memory perceives a single path from root to current node. In fact the "Time" from this point of view is not one dimensional – it seems one-dimensional only thanks to our perception.

    vongehr
    I agree more or less, but that is then multiple minds rather than multiple worlds.
    Perfect! Minds don't weigh anything or take up any room so they can all be fitted into the same skull. I knew we'd get there in the end.
    vongehr
    Minds don't weigh anything or take up any room
    Neither do worlds actually, not even room, as infinite universes can be squeezed into finite bubble universes in the inflating background via curving into the time direction!
    Neither do worlds actually, not even room, as infinite universes can be squeezed into finite bubble universes in the inflating background via curving into the time direction!
    That's the way! I knew you'd see a third possibility if you just thought about it for a moment. Get rid of realism? Nah! Get rid of locality? Nah! Get rid of location itself - that's the key: no need for spooky action at a distance if there's no room for any distance.

    Oh, but wait a minute! Wouldn't we have noticed if we lived in that sort of universe? Drat. Another one bites the dust.
    Quite an irony indeed ;o))) Truly, the existential perception is defined by ability to comprehend...

    vongehr
    You touch on a very important point that I have just these days unsuccessfully tried to get across to a very smart guy working on QM, a point that it seems almost nobody else understands and lies at the very core of the EPR paradox and its resolution and why people go silly about it:

    IF you assume direct reality (~world being "really out there"), locality is obviously crucially relevant.

    IF however you modify realism, in some sense, suddenly all can as well be made out of green cheese (poetically speaking, just to get a certain feeling across, not that I actually mean it literally): Locality has no longer the deep relevance it had.

    If people understood this, the whole debate would be almost over. For example, the guy I mentioned argues that QM is non-local yet also not EPR-real, and he thinks that this is some big difference to what I and others say and he fights to publish it. If he were to look up from his damn math and once in a while just look at the wider picture, he would see that there is no point in what he tries to do. With modal-realism in place, he already has locality or not pretty much as he pleases for free.

    That is one of my main points and I should write another article about this soon, to once more explain that the choice is not between either locality or realism to be modified. It is much much simpler. Spooky action at a distance already makes realism pretty damn "unreal". So you modify realism anyway. So just seriously modify it already, and then it just is not necessarily "local modal-realism" only in a very certain, Einstein local (micro causality) sense, while of course being from the classical point of view non-local [Just like QM gives us non-determinism in our classical world while actually being fully determined (unitary)].
    My understanding is that Bell's theorem proves localism wrong irrespective from realism, or am I missing something? I am not aware that it assumes realism in its formulation. How can we then trade realism to save localism, since Copenhagen interpretation, for instance, accepts neither?
    The reason for defending realism is obvious, however: if you give up realism, you end up with a purely phenomenological "theory" ("shut up and calculate!"). But a purely phenomenological theory is no theory at all, is a praescription, bearing no explanatory value. If we accept that, there is actually no meaning, for instance, in looking for a "unified theory", since unification makes no sense if we cannot say that the artifact A in theory X refers to the same "real" entity as the artifact B in theory Y. If General Relativity and Quantum Mechanics are not "realistic", their models are incommensurable and even conceiving their unification is absurd. One can accept that conclusion, but I wonder if anyone would ever really embrace this standpoint.
    Obviously, the world is not bound to behave so as to "save" the epistemologic soundness of Physics. But if you are a strumentalist, you have to accept "realistic" theories (like Bohm's, or "physical" intepretations of wave function collapse) as equally "effective" as any other; therefore, going for realist theories is mandatory if realism is true, and as good as any other approach if realism is false (or undecidable, I assume).

    vongehr
    My understanding is that Bell's theorem proves localism wrong irrespective from realism
    Why then is it stated as proving "locally realistic" or "relativistic locally micro-causal" theories wrong in the first place? If you were right, there would be no point in mentioning more than locality.

    "Realism" is a god of the gaps in retreat and, just like with "god", everybody means something different, so lets not focus on realism.
    How can we then trade realism to save localism
    Locality is saved when Alice's local world "splits" the moment the future light-cone* of Bob's measurement intersects it. In this case, there is no already determined Bob out there in a branch he shares with Alice (= "realism"?!?) while the light (real split) is still racing through the real branches (like in the Wiener Sausage) or worse, the split travels in an instant.

    [* You may object that light cones demand a real space-time, but Alice's past light-cone (what she knows, her minds memory) and physics that happens on her cone's surface is an equally valid description, and it does not have a real Bob.]

    a purely phenomenological theory is no theory at all, is a praescription, bearing no explanatory value.
    I do not understand this. Physics, if it ever comes to some sort of an end, must ultimately be about what observers can be consciously aware of, however much measurement apparatus and scientific method intervene. The real world out there is just a useful description, especially when doing classical physics.

    realist theories is mandatory if realism is true, and as good as any other approach if realism is false (or undecidable, I assume).
    If you mean by this that all physical theories must work in some sort of space (Hilbert space/phase space/manifold/spin-foam/...), then you may be right - Immanuel Kant would agree, too. But "realism is true" usually implies a more stubborn, misleading attitude. Locality once "obviously" belonged to true reality. What will realists throw out tomorrow? Objectivity?
    Sasha, you call Realism "old", "worse-than-religious", "stubborn", "misleading", not really drawing from the scientific lexicon. Still, you have very little to prove it wrong, and practically nothing to replace it. As far as I can understand, a "non-realistic" theory is "local" in a very trivial sense, since it does not acknowledge anything but the "here-and-now" phenomenic description of experimental data.

    You may dislike Realism, and, yes, it is a fact that you don't need to accept it, but this standpoint is scarcely a conquest of "modernity", let alone an unassailable Truth. It is, at best, a possible interpretation of evidence, and it bears a bunch of philosophical problems that are very attractive but (well, perhaps only for us old-fashioned devotees of gilded idols) nasty enough (you mention objectivity, for once, and I would really care to read a _solid_ definition of objectivity in a non-realistic framework).

    vongehr
    you call Realism "old", "worse-than-religious" ...
    What??? Any references - I do not remember saying anything like "worse-than-religion" ever. You having a bad day or something?
    you have very little to prove it wrong, and practically nothing to replace it.
    We have quantum physics for starters, secondly I am not out to prove ill-defined concepts wrong (waste of time trying to nail jello against the wall), but to improve terminology (replace insufficient one) so that actual progress can be made.
    "local" in a very trivial sense
    Micro-causality is trivial?!? Go tell the high energy particle, string, etc. physicists - good luck with that.
    Hi Sasha, just to clarify, your quote:
    "I am not going to tell you that you should refuse realism, plainly because “realism” is anything to anybody. It is worse than “god” in that respect"
    - "in that respect", I argue, believing in realism is a "worse than religious" standpoint. I could have written something like "worse than believing in something as scientifically ill-defined as God, with an analogously acritical attitude", but it is a bit lengthy. However, if it misinterprets your point, my apologies, but I wonder if it is correct that your point was that realism is a sort of "traditionally fideistic" attitude. An unfair allegation, in my view, but whatever.

    About quantum physics replacing realism, I'd say not really: there are some flavors of QM interpretations that are not realistic, like the one you are endorsing, and other ones (Bell himself was a realist, and so are many physicists today, of course) that are realistic (yet nonlocal, etc.), so QM leaves room to alternatives but should not be seen in itself as alternative to realism. You are free to propose the "replacement" of a concept, and you are not obliged to prove anything wrong, but without proof your case for arguing that the "old" one is "ill-defined" and "insufficient" does not hold water just because you find the "new" one more persuasive.

    And, just to be clear: I appreciate a lot the effort that you and other bloggers here are doing to divulge such stimulating and challenging topics. I just don't subscribe to the sharpness you use in disposing of some opinions as they were hopeless and anachronistic, while the jury is still out.

    vongehr
    worse than “god” in that respect
    OK, point taken. I meant here rather the amazing feats of sophistry in redefining a term so often and so much that it doesn't help in any conversation anymore (like in ours) in order to in the end be able to claim that one never gave it up and it was a good term all along. So, this was just about the god of the gaps, rather than religious zealots. Sorry about the misunderstanding.
    About quantum physics replacing realism
    Maybe not replacing rather than triggering yet another round of redefining it. I am not out to fight against realism, whatever that is (structural, functional, modal, ...) - I draw attention to the fact that there are two parts to local realism, and locality is not the one we should modify.
    And, just to be clear: I appreciate a lot the effort that you and other bloggers here are doing
    Thank you - and I too truly appreciate your interesting comments. I am sure that not only I but also others learn from it. I will in future be more careful about claiming anti-realism (maybe expressing it as the option of modifying the realism part of "local realism" is actually fully acceptable to you).
    "I appreciate a lot the effort that you and other bloggers here are doing"

    Sascha, I would like to add my enthusiastic agreement and thanks as a reader who has appreciated this series of posts immensely, including the careful clarifications you and Ulrich take the time to give in comments. It has helped me greatly in my own understanding of the implications of the Bell/Aspect results.
    I confess I have difficulty grasping how "non-locality" satisfies as an explanation... perhaps (tongue in cheek) it's somehow related to John Wheeler's comment that Feynman related in his Nobel speech:


    "Feynman, I know why all electrons have the same charge and the same mass."
    "Why?"
    "Because, they are all the same electron!"
    (full excerpt at wikipedia "One-electron Universe")