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Everything posted by ttn

  1. One other question about this. It's true that in Bohmian Mechanics (which as I explained is what I actually advocate) particles that are "potentially millions of light years" away from each other can be "linked", i.e., can affect each other. Of course ultimately this is a question for experiment. It is impossible to speculate about what limits in terms of distance or propagation speed might exist for these effects. Maybe, for example, the effects aren't "instantaneous" but "only" a billion times faster than light, and maybe they can only extend across a distance of 100,000 light years, not a million. All that experiments done so far tell us is that there is some kind of nonlocal causality involved that involves propagation of at least several times the speed of light and can extend over at least several kilometers. But anyway it is true that Bohm's theory contains an instantaneous action at a distance between particles. My question is: what precisely do you object to here? I'm guessing you wouldn't want to say that you would have rejected Newtonian gravitation had you been alive 300 years ago. Yet that theory also asserts instantaneous action at a distance between particles. So what's the difference exactly? Why the contempt for the former while the latter is properly held up as a shining example of rational physics? Of course, Newton himself didn't believe in literal action at a distance, and subsequent history has shown that one can understand Newton's law as simply the limit of a field theory with a finite propagation speed. So the real question is: what in the world makes you think the same won't be possible for the analogous laws in Bohm's theory?
  2. If you find the non-locality implied by "quantum entanglement" so objectionable, why then would you advocate TEW? It too is non-local, as I explained in painstaking and exhaustive detail here. (By the way, TEW's failure to account for the results of the EPR-Bell experiments locally, as its author claims it does, is not the only problem with it. The theory is incoherent or just wrong in a number of other ways. But it's convenient to focus on the Bell issue since it is so cut and dried.) But the bigger problem is this: if you object to non-locality, your problem is with nature, not with any particular theory. Bell's theorem proves that no theory satisfying Bell Locality can be consistent with the reasonably-well-verified QM predictions. So if you think theories should agree with experimental data, you just can't have a Bell Local theory. It just isn't possible. Until you (and whatever other few advocates of TEW remain) grasp this -- i.e., understand Bell's Theorem -- you will continue to bash your head against the wall of reality and make yourself look like a fool doing so. All I ask is that if you or anyone else insists on doing this, you not associate yourself with Objectivism while doing it. I don't mean to be rude or insulting, and I don't know you nearly well enough to know whether you're deliberately distorting things here or just honestly confused. I'm certainly willing and inclined to assume it's the latter. If so, you simply need to understand Bell's Theorem better. Get Maudlin's book and read it. Or read one of Bell's relatively accessible articles such as "Bertlmann's Socks and the Nature of Reality" (which is by the way completely brilliant and wonderful to read). But the theorem exists, and you really just can't take the position you're taking here unless you refute it (which I'll bet my life isn't going to happen). Understand and accept the theorem; understand and refute it; or don't have a position either way on this issue. Those are really the only three honest options. By the way, it is preposterous to call me an advocate of "conventional QM". I am (with certain qualifications) an advocate of Bohmian Mechanics, a theory which has been repeatedly proved to be impossible by bogus proofs, systematically mis-understood, mis-characterized, and mis-represented by commentators, systematically ignored by physicists and in particular textbook writers, dismissed for reasons that are entirely bogus or inconsistent or which represent actual virtues of the theory. In short, my favored version of QM is *anything* but conventional. If you don't know enough to know the difference between Bohm's theory and Bohr's theory, you have no business holding a position on TEW or any other aspect of this issue.
  3. I can't believe that people are still seriously advocating TEW. It's probably a good thing for interested young physicists to read Little's paper -- but only as an exercise in physical and philosophical detection. You must go into it knowing that this theory does not work. Let me be specific lest there be any confusion. TEW is inconsistent with certain experimental facts, certain correlations which are predicted by orthodox QM and which have been validated in the lab. In his original paper, Lewis Little claimed that there was an error in the experiments, and that a corrected experiment would demonstrate disagreement with the QM predictions and agreement with TEW. Then he changed his mind (perhaps when he realized that other experiments already existed which did not have the alleged shortcoming he had pointed to earlier) and said that the experiments and the QM predictions were correct. He thus modified his theory so that it would make the same predictions as QM. But this modified version was riddled with errors, and was retracted when those errors were pointed out. Click here for the announcement of that retraction, but stick around and look at the other messages leading up to and then following it. More recently, Little put forward yet another version of the theory which he claimed was able to explain the experimental results without nonlocal (i.e., superluminal) causation. But this is simply not the case. The paper is vague, but to whatever extent this latest version of the theory is local, it disagrees with the experiments; and to whatever extent it agrees with the experiments, it is not local. (See, for example, here and here.) None of this is a surprise, given Bell's Theorem. This theorem proves that no local theory can explain the observed correlations. Period. End of story. This means that Little's whole approach is doomed from the start, that his (and his followers') philosophical attacks against already-existing non-local hidden variable theories are revealed as complete rationalism, and that (of particular relevance here) any association of Little or his theory with Objectivism is a complete disaster for the latter. I recognize that many honest people may not be in a position to assess the technical evidence on this issue. Such a person is in the position of having to accept "expert testimony" (or, better, to simply refrain from having an opinion on TEW). I would simply like to urge anyone in that position to at least recognize that certain experts believe not only that TEW is wrong, but that it is crackpot pseudo-science which should never, under any circumstances, be assimilated to or associated with Ayn Rand and Objectivism. In particular, I urge anyone who cares about Objectivism to think twice before you advocate publicly for TEW. I should also mention that nobody who is interested in this topic should be satisfied with expert testimony. The issues are actually not very technical or difficult. A good place to start would be Tim Maudlin's spectacular book, "Quantum Non-Locality and Relativity." Reading some of the (less technical) papers in J.S. Bell's "Speakable and Un-Speakable in Quantum Mechanics" would also be a very good idea. But perhaps the best starting point for someone who knows some physics and wants to get a rational toe-hold into quantum mechanics, would be Sheldon Goldstein's online article on Bohmian Mechanics.
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