X-Message-Number: 8514
From:  (Thomas Donaldson)
Subject: To John Pietrzak
Date: Sun, 31 Aug 1997 13:42:47 -0700 (PDT)

Hi!

I have several points to make about John's comments. First of all, there are
problems with the original Turing Test. The main problem is that it does not
take account of the fact that we must live in a world which involves more 
than language. Sure, we talk to one another, but we also drive cars, walk to
places, see things for ourselves, etc etc. Our abilities to do these things
do not depend on our ability to carry on a conversation. The Turing Test 
looks only at one part, and a small part, of the tasks which our brains do.

Not only that, but in living in the world, we learn the meaning of all the 
various words we use to talk to one another. Ultimately that meaning cannot
be defined by other words. This may seem a subtle point, but it should not
be. Underneath all the symbols we use to DESCRIBE the world we all have 
perceptions of the world.

As for the ability to pass a Turing Test, or to do calculations, we CAN do
that. But when we look at the actual circuitry of our brains, we do not
find similar circuitry in computers. When I said that we weren't organized
the same way as computers, I was referring to the organization of our brains.
At a sufficiently abstract level it remains fair to say that we are organized
the same way --- but then at a sufficiently abstract level we and computers
are organized the same way as a seashell or a bit of granite.

One major difference, to which I am particularly referring, is the speed 
with which we can perform the same tasks as those of a computer. Yes, speed
is omitted from the Turing Test (should it be?). In practical terms, speed
is very important. It's important within computing and in other cases too.
And when we put it into the hopper, we discover an obvious truth: not even
all COMPUTERS are the same. Limitations of memory also raise practical 
problems, too. Any abstract theory which does not grapple with such issues
leaves some serious questions quite open. And I say this in the context of
computing, not neuroscience or neurology, or even the significance of the 
Turing test... if we expand matters beyond normal "computing", we run
into still other issues, to which I alluded in the previous paragraphs.

Taking in mind these practical issues, I don't believe the Turing Test gives
us nearly enough information. As for the organization of human brains 
compared to the organization of computers, my own reading --- which has
gone on now for years --- in neuroscience suggests to me that our brains 
consist of a collection of neural nets (of a kind that so far does not 
exist except in living things --- I do NOT exclude the possibility of 
making such devices) connected by a very simple sequential system which
gives us our awareness. Neural nets aren't programmed, they are taught;
they can also carry out recognition tasks that normal computer organization
of the same number of chips would find impossible. A corollary is that our
memories are stored in the same "chips" (otherwise known as neurons) which
carry out the processing. They are stored distributed among many such chips,
not just one or a few.

Yes, a computer organized as ours are could imitate this form of organization,
and thus do such things as learning to recognize faces. However this ability
corresponds to our own ability to carry out calculations just like a computer:
neither one is really adapted to that task, and thus when it does such tasks
does them more slowly and inefficiently than would a device designed to 
do them especially.

			Long long life,

				Thomas Donaldson

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