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From: bill@milford.UUCP (bill)
Newsgroups: net.math
Subject: Re: Mind as Turing Machine: a proof *and* a disproof!
Message-ID: <110@milford.UUCP>
Date: Thu, 7-Nov-85 12:30:29 EST
Article-I.D.: milford.110
Posted: Thu Nov  7 12:30:29 1985
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Henry Schaffer (hes@ecsvax.UUCP) wrote:

> Following this path, the rephrased question is "Can the mind be modelled
> by a Turing machine?", and it can't be answered by showing speed 
> differences -- but it could by showing that the mind can "compute" 
> something that a Turing machine can't.  (Vice-versa isn't possible, because
> it is evident that the mind can simulate a Turing machine.)
                     ^^^ ^^^^ ^^^ ^^^^^^^^ ^ ^^^^^^ ^^^^^^^
> --henry schaffer  n c state univ

and Thomas Breuel (breuel@h-sc1.UUCP) wrote:

> What you really want to know is whether the human brain is 'Turing
> equivalent'.  I think with fair certainty it can be said that it is
> not, in the same sense that a general purpose computer is *not*
> Turing equivalent: both don't have infinite memory. Both are much
> more accurately captured by the notion of a finite state machine.
                                            ^ ^^^^^^ ^^^^^ ^^^^^^^

I agree with both, the only problem is the old philosophical question
of 'mind' =? 'brain' sneaks into the picture (usually called the Mind/Body
question.) The brain quite obviously is a finite state machine but through
the use of exterior memory media (my desk, my computer files, etc.) 
the mind can emulate devices requiring arbitrarily large memories and
access.

A more interesting question here might be "What type of machine can accept
an arbitrarily chosen natural language?" I suspect that English is not
a regular language nor a context-free language; is it context-sensitive?
Is it more??

Sometimes I know my mind is only like a Mealy machine, quite often its
only a finite state automata; but ideally I guess its a linear-bounded
automata.