X-Message-Number: 8673
Date:  Mon, 13 Oct 97 16:53:23 
From: Mike Perry <>
Subject: Re: CryoNet #8670, 8665

Thomas Donaldson, #8670:

> To Mike Perry:
> AS for Turing Machines, I've said repeatedly that they are abstract ideas and
> fail to capture some very real issues in computing: such as speed and the
> finitude of memory. This is not a criticism of Turing machines as such; the
> point is that in some areas and for some problems they tell us nothing at
> all.
No real argument there.
> The reference (which specifically sets up a neural net which cannot be 
> emulated by a Turing machine) is by HT Siegelmannn, ED Sontag, in SCIENCE
> (268(1995) 545-548). Naturally they give more information and references
> themselves.
Thanks. I intend to look up this reference and study it closely. I'll 
be pretty surprised, though, if it refutes Turing's thesis.
> Given the practical problem of a Turing machine trying to emulate a human
> brain (with billions of nodes in its neural net) the issue of whether or
> not our brain might be such that it COULD NOT be emulated even with millions
> of years of time, the question of whether or not it can be emulated by a
> Turing machine for the reasons given in the article above --- seems kind of
> moot. We already know we can't emulate a brain PRACTICALLY. It is a matter
> of intellectual interest if we find we can't do so even abstractly. 
To me there it is a vitally important consideration in the question 
of whether in principle a human could be emulated by a Turing 
machine, even if we ignore the practical issues completely. That is, 
it tells us about our basic natures--do we have mystical "souls" for 
instance, or are we explainable in purely materialistic terms? I 
incline strongly to the latter view (which doesn't require that we be 
glorified Turing machines, but arguing that we are is one feasible way of 
arguing this position), and develop this point in the book I am 
writing. I should add that the information paradigm gives us more to 
go on than merely saying we are material in some sense--it 
demystifies materialism and strengthens other arguments I am trying 
to make.

I would also like to thank John K. Clark for his posting on quantum 
encryption, #8665.

Endless Best,

Mike Perry 

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