X-Message-Number: 107
From arpa!A.ISI.EDU!TKD Wed Jun 28 09:01:06 EDT 1989
Date: Wed 28 Jun 89 09:01:06-EDT
From: Thomas Donaldson <>
Subject: Re: CRYONICS #104 - Re: Brain Computational Memory Limits
In-Reply-To: Message from "" of Tue 27 Jun 89 20:14:55-EDT
Message-ID: <>
Status: R

Dear Ralph:

If I understand your reply, you are saying that the SOLE significance of
your paper is to provide convincing evidence that human beings will 
someday be able to make computers capable of vast and imposing thoughts.

The issue I was raising was that of whether "computational power" is any
longer a useful concept.  If your brain-imitating computer is actually
sequential, then of course we can use calculations about computational 
power.  If we have to duplicate the network anatomy of the human brain to 
get a similar "power", the CONCEPT needs revision.  Nor do I think that
however powerful it will obviously follow that this duplicate brain
wouldn't be slowed down by bottlenecks (catastrophically slowed down!) if
it tries to duplicate a brain with the WRONG network architecture.

Underlying this abuse of power lies Moravec's argument.  Ten years ago Hans
(sorry Hans!) was putting this same position, and predicting that enough
"computational power" would be available in 1990.  I am doubting that
computational power is a good measure either of the time we will take to get
AI or the time needed for computations of other kinds.  That's all. 

Incidentally, though, we have brains to make choices, not to make computations.
But that is (agreed!) a complex subject bearing on AI and other things.

As for your abuse of power, it seems an awful lot of machinery to convince
us of something we would already agree on.  What audience is your paper 
designed for?  I find that hard to place.  Why power?  Isn't that perhaps an
awfully macho idea?  Do we have a lot of BIG MEN going around comparing 
their muscle size and their computer power?

			Thomas Donaldson

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