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Article 3816 of comp.ai.philosophy:
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>From: weemba@libra.wistar.upenn.edu (Matthew P Wiener)
Newsgroups: comp.ai.philosophy
Subject: Re: QM nonsense
Message-ID: <66424@netnews.upenn.edu>
Date: 18 Feb 92 00:24:38 GMT
References: <1992Feb17.170325.11489@oracorp.com>
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Reply-To: weemba@libra.wistar.upenn.edu (Matthew P Wiener)
Organization: The Wistar Institute of Anatomy and Biology
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In-reply-to: daryl@oracorp.com

In article <1992Feb17.170325.11489@oracorp.com>, daryl@oracorp writes:
>These two facts seem to support von Neumann's position that there are
>two kinds of quantum processes, ordinary processes that obey the
>Schrodinger equation, and observational processes that cause the
>collapse of the wave function. If this "two process" solution is to be
>taken too literally, then it seems either that the Schrodinger
>equation is incorrect for describing the behavior of physical systems,
>or that human minds are *not* physical systems.

This is why the "quantum measurement" problem exists.

>I don't think that either position is justified. Everett, DeWitt, and
>others working in the 50's developed a so-called Many-Worlds
>interpretation of quantum mechanics (although that name is misleading,
>in my opinion). According to this interpretation, there is just one
>type of process, and that is described by the Schrodinger equation.
>The appearance of type-2 processes is purely subjective.  [...]

One must still explain why mind has this subjective relationship to
the "many worlds".  It does not eliminate the QM/mind question, it
just calls it something else.

The approach that I favor is the MW-inspired interpretations of Zeh,
Zurek, Gell-Mann, Hartle, and others.  Some of the most recent work on
this can be found in Zurek (ed) COMPLEXITY, ENTROPY AND THE PHYSICS OF
INFORMATION.  Briefly, their view is that the environment is part of
the measurement process, and you can achieve decoherence by letting
the environment absorb QM coherence.  Model calculations provide, for
example, an answer to Einstein's "is the moon really there when no
one looks at it?"--yes, since the cosmic microwave background absorbs
the moon's quantum uncertainty.

This still doesn't eliminate the QM/mind question, and in fact, GM&H
make the point in their Zurek contribution that a brain that decoheres
its quantum inputs should be evolutionary favored because of greater
predictibility over coherent input.
-- 
-Matthew P Wiener (weemba@libra.wistar.upenn.edu)


