Newsgroups: sci.physics,comp.ai.philosophy
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From: daryl@oracorp.com (Daryl McCullough)
Subject: Re: Roger Penrose's New Book (in HTML) 1.0
Message-ID: <1994Oct20.134514.18843@oracorp.com>
Organization: Odyssey Research Associates, Inc.
Date: Thu, 20 Oct 1994 13:45:14 GMT
Lines: 38
Xref: glinda.oz.cs.cmu.edu sci.physics:96982 comp.ai.philosophy:21151

firth@sei.cmu.edu (Robert Firth) writes:

>...Two universal Turing machines cannot be programmed to replicate the
>behaviour of two correlated photons.  If they could, a local hidden
>variable model would work and Bell's Inequality couldn't be violated.

What does that have to do with Turing machines? Two human beings would
have no better luck in replicating the behavior of two correlated
photons (unless they used correlated photons). Do you conclude,
therefore, that the universe is inhuman as well as noncomputable?

The issue is not computing power, it is nonlocal correlations.  There
is nothing noncomputable about the results of the EPR experiment; they
are completely described by an equation like:

      P(detector A and detector B both detect photons)
      = 1/2 cos^2(theta) where theta is the angle between
        the orientations of the two detectors

I don't see any way to use quantum nonlocality to solve any
mathematical problems that are not solveable by a Turing machine.

>The real world is non (Turing) computable at a very basic level.

In what sense?

>Since it is our general experience that macroscopic systems have
>"emergent" properties but not "de-emergent" ones, it seems only
>reasonable to conclude that, if a pair of photons is non computable,

In what sense is a pair of photons non computable? Do you just
mean "nonpredictable"?

>no organised larger physical system can be Turing computable, and
>strong AI is based on a false premise.

What premise is that?

