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Article 3848 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: <66559@netnews.upenn.edu>
Date: 18 Feb 92 23:28:14 GMT
References: <1992Feb17.170325.11489@oracorp.com> <66424@netnews.upenn.edu> <ABOULANG.92Feb18163624@icarus.bbn.com>
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Reply-To: weemba@libra.wistar.upenn.edu (Matthew P Wiener)
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In-reply-to: aboulang@bbn.com (Albert Boulanger)

In article <ABOULANG.92Feb18163624@icarus.bbn.com>, aboulang@bbn (Albert Boulanger) writes:
>  >There has been some recent experimental work on QM measurement that
>  >indicate that the extremal position of conscious-driven wavefunction
>  >collapse is not workable (machine driven watch pot experiment). Here
>  >is a copy of a posting from sci.physics:

>  And I responded to your posting then, in the same way I'm responding to
>  Stanley Friesen: it does not rule the extreme view out, since they still
>  make the same experimental predictions.

>Can you please state what you have in mind as the "extreme view".

I thought I meant what you meant by "the extremal position" above: namely
that only consciousness is capable of collapsing wave functions.

>  All the experiment can do is emphasize experimentally just how weird the
>  extreme view is.  Schroedinger's cat was the first theoretical description,
>  and the debate is still alive.

>But you do not have to have some conscious entity set up a watch pot
>arrangement. It could of just happened without anybody conscious
>constructing it. No?

Right.  Meanwhile, what state is it in?  By some interpretations, it
can collapse on its own, by other interpretations, it cannot.

>		       Does this not rule out the necessity of a
>conscious-driven wavefunction collapse. We are just part of the
>enviroment to decohere with.

No experiment can rule out an interpretation that agrees with it.  The
most that can be done for now is that one interpretation makes the most
sense overall and becomes the party line.  I think the Zeh et al one
I mentioned has the best chance of that.  Unification with GR may also
be relevant, or working QM based AI: either could give one particular
interpretation a decided advantage.

>   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.  [...]

>Yes. Decoherence via the extrernal enviroment is a clarifying notion.
>Ok. I guess what I had in mind as the extreme position was that it is
>*necessary* for a conscious observer for wave function collapse. (I
>thought this was the historical notion.) I think your position is
>that wave function collapse can be *enabled* by conscious
>observation, and furthermore one could not experimentally separate
>out the sources of decoherence. Is this right?

That sounds about right.  "Wave function collapse" sticks out rather
inelegantly, and any interpretation that makes it a natural without
creating replacement inexplicable and inelegant mechanisms is a winner
in my book.
-- 
-Matthew P Wiener (weemba@libra.wistar.upenn.edu)


