X-Message-Number: 14735
Date: Thu, 19 Oct 2000 07:04:41 -0400
From: Thomas Donaldson <>
Subject: 3rd piece on computers and brains

HI everyone!

Once more and this will be the last (for a while) on this subject. John
Clark raises basically 2 questions:

1. If you don't use symbolism how do you think about the Sun?

The thing to do here, to understand about symbolism and its use, is to
consider (say) the thinking of a primitive mammal. (We ourselves developed
from primitive mammals and retained their means of thinking). The
rat, say, doesn't think about the Sun as such. Instead his brain works on
the sensory impressions he's received: warm, light, all from a particular
location. And it's that kind of thought, rather than mulling over the
workings of sunspots, which does not require symbolism.

Yes, there are thoughts we can have that do require symbolism. But 
fundamentally, even to learn the meaning of symbols, we must have another
system which deals more directly with the world.

2. The Internet makes and breaks millions of computers every second.

An interesting point. The Internet does do this, but in doing it is it
acting as a computer at all? However there is more to this issue: the
main difference is simply that all those millions of computers are
not taking part in any common program. And yes, I'm well aware of 
computing projects which use the Internet and computers attached to
it to do the calculations (though to my knowledge no such project
has simultaneously used millions of computers). The major difference
here between such a system and our brains is that the connections 
are created and destroyed not by the owners of the computers used
but as part of the system itself... with a minor (perhaps important)
difference also coming from the difference between one neuron and
a Pentium with memory, hard disk, etc. Put simply, in such computer
projects the disappearance or adherence of a computer comes because
its controller decides to do so. The disappearance or formation of
a nerve connection happens because of events in the working brain.

Finally, I will point out that the existence of machines which don't
follow Turing is already fully accepted. The possibility of machines
which not only don't follow Turing, but actually do activities which
look a bit like computing (until you look at them in detail) doesn't
obviously cast any aspersions at all on all the work which has been
done to understand computers and computing.

		Best wishes and long long life to all,

			Thomas Donaldson

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