X-Message-Number: 9261
From: Thomas Donaldson <>
Subject: Re: CryoNet #9253 - #9255
Date: Wed, 11 Mar 1998 00:49:36 -0800 (PST)

Hi!

In discussing the counterexample in depth I am a bit at a temporary handicap
here because I've packed away the issue of NATURE in which it was 
presented, and so would have to search for the reference and get the
article some other way (I'm moving, you see, and everything is going into
boxes. You won't even have to put up with me for a while, until I get
a new modem and new net link).

As for Fields medals, it's not clear this would count as mathematics. And
Fields medals, for reasons unknown to me, also have an age limit which the
Nobel prizes do not. (Seriously! If you are 60 years old, and prove the most
califragilistic theorem in the known universe, you won't be eligible for a 
Fields medal). But that is an aside...

I did give the explicit reference to the paper in which this example was 
presented on a previous Cryonet. As I recall, the only thing that was
done with the neural net was to make some of the links between nodes
incommensurable. The rest consisted of discussion of just what this would
mean. This is my MEMORY of the result, not the same as the paper, and I
don't claim my memory to be all that good. And no, it was NOT a trivial
counterexample at all.

Since it is an important result, at least for those who base their 
philosophy of life on Church and Turing, then I shall try to recover it.
Mike, who I gave it to originally, will hopefully enter the discussion 
with that reference. I could then find it easily, just like you. 

I don't believe we can have an productive discussion of this issue without
it. And once I am in Australia and all the boxes are emptied, I'm happy
to take up this subject again. I do agree that it's worth discussing.

HOWEVER, there is a larger issue which I WILL discuss. Computers now, and
for some time in the future --- possibly to a time in which the entire
notion of what a brain or a computer is vanishes into the past, with both
ideas considered inadequate concepts --- will provide at best clearly 
inaccurate models of brains. One major problem with a computer model of a 
brain is that connections change between neurons: you don't have circuitry
which remains constant. Brains are 3-dimensional, too, so that it becomes
difficult to adequately map their activity on a 2-dimensional surface.
I very much do NOT mean to say that we cannot build devices which ARE
good models of brains, merely that they would not qualify as computers.
I'll also add that I see no reason why the plan for my brain or your
brain could not be stored, statically, in a computer. (It's getting it
to work right where the problems come).

Nor can we infer anything about the behavior of brains from that of 
computers. Among other points major for cryonics, we aren't going to 
get any idea of whether or not we can be brought back from present 
suspensions by thinking along the lines of computer science. A big slab
of neuroscience will be needed here. 

I have been a professional programmer myself, in parallel computing, and
I would be the last to say that computers are not valuable. But I get
this feeling, hearing some people on Cryonet and elsewhere, that some
people now have decided they have a hammer (computers and all the theory
of computing behind them) and consequently everything else in the universe
is a nail. Me, I'm glad I have a hammer, but I've got lots of other tools
too.
			Best wishes, and long long life,

				Thomas Donaldson

PS: And I really do mean it about taking up this discussion once I'm
in Australia. I fly there on 18 April, and will be there for at least 2
years. There are net nodes available there, and I'll try to get one, and
a modem suitable for Australia (THAT issue can go on for pages, but not now)
and get back on Cryonet. I'm not trying to avoid the issue, it's just that
I feel I can say little right now. And if Mike Perry puts the reference
on the net again, then we can all read it and have SOME background for
discussion.

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