Newsgroups: comp.ai.alife
From: Chris@smithg.demon.co.uk (Chris Gordon-Smith)
Path: cantaloupe.srv.cs.cmu.edu!das-news2.harvard.edu!news2.near.net!howland.reston.ans.net!swrinde!pipex!demon!news2.demon.co.uk!news.demon.co.uk!smithg.demon.co.uk!Chris
Subject: Re: info on CA's (the universe as a CA)
References: <dobrzelewski.140.2F9E6A15@cvm.msu.edu>,<3nm4pv$s5r@gap.cco.caltech.edu> <3nmibj$r8h@fnnews.fnal.gov> <1995Apr27.142811.15117@zippy.dct.ac.uk> <dobrzelewski.143.2F9FB133@cvm.msu.edu>
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Date: Sat, 29 Apr 1995 00:05:17 +0000
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In article <dobrzelewski.143.2F9FB133@cvm.msu.edu>
           dobrzelewski@cvm.msu.edu "Joel Dobrzelewski" writes:

> 
> >Well, in a way it is possible to say that the universe is a CA, in the same 
way
> >that it is possible to say that the whole universe is a set of differential
> >equations. 
> 
> there seems to be a little confusion...  i know CA's are useful models.  
> however, i'm not talking about models.  what i'm talking about is the 
> possiblity of: THE UNIVERSE IS ACTUALLY A CELLULAR AUTOMATA. 
> 

As Eli Meir indicated in an earlier posting in this thread, some aspects of 
Quantum Physics seem to display non - locality. A system which preserves 
locality is one in which the behaviour of each quantum mechanical particle 
results from the properties of the wave function in the region where the 
particle happens to be. The experiments of Alain Aspect show that there can be 
a correlation between photon events in space-time even though the two events 
may be distant from one another such that a signal from one to the other would 
have to travel faster than the speed of light.

I believe most of us tend to think of a cellular automaton as a system in 
which each cell is affected by the state of other cells in its neighbourhood, 
rather than one in which distant cells affect each other (although I suppose 
such a CA would be possible).

It seems to me that the nature of the universe at the quantum mechnical level 
is still not that well understood, and the subject of considerable debate. For 
example, the 'many worlds' interpretation of quantum mechanics defies common 
sense but is taken seriously by a some (but by no means all) physicists.

Personally I would like to believe that the world is a CA, because I like the 
idea of complexity out of simple rules. However, its not obvious how this 
would  fit in with the idea of non-locality in quantum mechanics.

From the point of view of Alife and AI, the key question is whether or not 
quantum mechanical effects actually matter. It may be that the course of 
evolution and the development of consciousness would have been the same 
regardless of whether the underlying physics was classical or quantum 
mechanical. On the other hand (as Roger Penrose suggests), it may be that 
quantum mechanics plays a fundamental role in the working of the brain and in 
consciousness.

If anyone is interested in this stuff, I would recommend the following:-

Quantum Physics: Illusion or Reality. Alastair Roe, Cambridge University Press. 
ISBN 0-521-27082-3.

Quantum Theory and the Schism in Physics. Karl R. Popper, Unwin Hyman (who have 
now been taken over by Collins and the Murdoch Empire). ISBN 0-04-445555-0. 

David Bohm has also written lots about this.

Regards

-- 
Chris Gordon-Smith
London
UK
Email: chris@smithg.demon.co.uk
