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Article 6226 of comp.ai.philosophy:
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>From: toe@wam.umd.edu (Lunatic Leo)
Subject: Re: Quantum mechanics (no AI here, sorry)
Message-ID: <1992Jun12.052430.3816@wam.umd.edu>
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Date: Fri, 12 Jun 1992 05:24:30 GMT
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In article <1992Jun8.150305.5307@guinness.idbsu.edu> holmes@opal.idbsu.edu  
(Randall Holmes) writes:
> In article <1992Jun6.133052.2816@oracorp.com> daryl@oracorp.com (Daryl  
McCullough) writes:
> >holmes@opal.idbsu.edu (Randall Holmes) writes:
> >
> >>>Randall, I think you are behind the times on this. Einstein *thought*
> >>>that a hidden-variables interpretation would explain the seeming
> >>>nonlocality of quantum mechanics, but John Bell in fact showed just
> >>>the opposite: the nonlocality *cannot* be explained by hidden
> >>>variables theories (Bell's Theorem).
> >
> >>It just isn't so.  I produced a hidden variables explanation of the
> >>behaviour of Mermin's device after about an hour of reflection (the
> >>reflection was required to recover my earlier thinking on the subject,
> >>which took a lot more than an hour!).
> >
> >>...Suppose that a device emits two electrons with opposite spin
> >>in opposite directions. [Describes EPR experiment]
> >
> >>This is supposed to establish superluminal communication between the
> >>two detectors.
> >
> >No, it is supposed to establish that Einstein's realism requires
> >superluminal communication. The idea that a particle has a definite
> >spin in each direction, we just don't know what it is, is ruled out
> >unless one wants to allow superliminal communication.
> >
> >>It establishes no such thing.  Here is an alternate
> >>hypothesis.  The state of a particle, when it is emitted, consists of
> >>a definite yes-no answer for each angle (not a hidden single axis of
> >>polarization -- Bell's argument does kill this). Each of these
> >>answers is diametrically opposed as between the two electrons.  The
> >>answers vis-a-vis two angles for a given one of the two electrons are
> >>correlated probabilistically in the appropriate degree determined by
> >>the angle.  This kind of hidden state, decided at the source, not by
> >>random events with space-like separation at the detectors, will
> >>exhibit the exact behaviour seen in the Mermin experiment and does not
> >>involve non-locality.  What is unclear is what the physical meaning of
> >>the state is, but that is already unclear in QM as it stands.
> >
> >Randall, research along these lines has already been done. It leads to
> >the idea of "spin-1/2 functions", which are functions from the surface
> >of a 2-sphere into +/- 1 such that the correlations are in accord with
> >the predictions of quantum mechanics. The existence of such functions
> >is very difficult to establish, and has a very high set theoretic
> >consistency strength. (I can't remember whether their existence is
> >actually independent of ZFC, or not.) Such a function would have to
> >be wildly discontinuous almost everywhere.
> >
> >Anyway, while I agree that there are *mathematical* possibilities to
> >circumvent Bell's Theorem, I don't think that there are any that a
> >physicist would take seriously. In the spin-1/2 function approach, it
> >is as if an *enormously* convoluted conspiracy were being perpetrated
> >to give the illusion of the simplicity of quantum mechanics.
> >
> 
> Well, at least I'm not behind the times!  Could you e-mail me a
> reference for spin 1/2 functions?  It actually occurred to me that
> constructing the array of random variables needed might be
> nontrivial...  I actually do think of the underlying reality behind QM
> as being a necessarily elaborate conspiracy to deny us certain
> information!
> 
> >>>
> >>>>The "non-locality" has to do (on my interpretation) with the fact
> >>>>that getting extra information about event A may immediately give
> >>>>me extra information about event B even if A and B have space-like
> >>>>separation
> >>>
> >>>That explanation has been pretty much ruled out. There is no way
> >>>to reproduce the statistical predictions of quantum mechanics by
> >>>such a hidden variables theory.
> >>
> >>I just did it.  The point is that the rather stringent conditions on
> >>Bell's Theorem are not satisfied by this hidden state hypothesis.
> >>Read the conditions.  What is true is that the hidden states have to
> >>be very complicated and the resulting theory will not be
> >>deterministic. A more succinct answer is that this is a hidden
> >>variables theory, but it is not "such" a hidden variables theory.

[etc...etc...etc...]
	There is a book by R. G. Hughes called "The Structure and
	Interpretation of Quantum Mechanics." It is no slouch of a book.
	I highly recommend reading it before bantering back and forth on
	the Net.
	My 2 cents:
		Many world's appears to violate Conservation of Energy.
	(of course in any one world-line there is no such problem)
		We needn't hang on to older ideas that proved useful in
	other conditions. Wavicles (wave-particles) have two different 
	space-like behaviors that CANNOT be modeled by ANY hidden variables
	theory. The "Collapse of the Wave Function" hitherto has NO 
	explination. So making assumptions about what causes the collapse ie,
	the "Conciousness Creates Reality" interpretation, are jumping the
	gun in a big way. 
		My biggest question is 'What causes the changes of behaivor
	of some quantum entity?'. But, I do not believe this is a discussion
	for comp.ai.philosophy .

					-L.L.


