Newsgroups: comp.ai.philosophy
From: ohgs@chatham.demon.co.uk (Oliver Sparrow)
Path: cantaloupe.srv.cs.cmu.edu!das-news2.harvard.edu!news2.near.net!howland.reston.ans.net!news.sprintlink.net!demon!chatham.demon.co.uk!ohgs
Subject: Re: Experimental evidence of quantum effects in consciousness
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References: <zlsiida.191.2EA78036@fs1.mcc.ac.uk> <HULTHAGE.94Oct24105829@torsk.usc.edu> <zlsiida.221.2EB0C578@fs1.mcc.ac.uk>
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Date: Tue, 1 Nov 1994 10:13:29 +0000
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One would need to see the paper to take a view. The idea that quantum
indeterminacy and collapse is somehow connected to an aware observer is
simply wrong, however. There are numerous examples of the so-called watched
pot or watch-dog effect, in which a quantum state is prevented from migrating
by repeated "observations" in which it is required to take on one state or 
the other. If these observations are close together in time, the probability
of a shift is relatively small for any one period and the system tends to
lock into the state in which it started for far longer than it other would.
The observer can be entirely passive and mechanical, however: all that matters
is an unequivocal interaction which locks down one of a pair of non-commuting
variables. A good example is the rotation of polarisation of a photon when it
passes through, for instance, a solution of sugar. 

Pass a photon into the solution through a polariser and measure its 
polarisation at the opther end: it has shifted. One measures the sugar content 
of grape juice in this way when making wine. So: sned in a stream of 
vetically polarised photons. Add one or more vertically-oriented polarisers in 
the path of the photon through the solution. At each, the photon either passes 
(having retained its vertical polarisation) or it is absorbed. The photon will
have been rotated by N degrees, where - if the space to the first polariser is 
short, N will be small: say, 10 degrees. The chances of its being absorbed (ie, 
behaving as though not vertically polarised) is sin2(N), which will be a number 
in the order of 0.02 when N is about 10 degrees. The probability that the 
photon will pass (and *be* vertically polarised at this point) is, therefore, 
0.98. A second filter will exercise the same effect, and the joint probability
that the photon will pass will be (1- 0.02*0.02). Several filters will make it
almost certain that the photon will pass and will emerge from the solution 
still in its vertical alignment.

This is not the *effect* of the polarisers but the effect *on* the probability 
that the photon woul dhave been rotated. The "observer" is a passive 
interaction, therefore.

 
_________________________________________________

  Oliver Sparrow
  ohgs@chatham.demon.co.uk
