Re: (OPE-L) Re: The Church-Turing thesis

From: Ian Wright (ian_paul_wright@HOTMAIL.COM)
Date: Mon Jan 19 2004 - 18:42:51 EST

Hello Jerry,

It is possible that human minds run on causal principles more general than
our current understanding of universal computation. It is of course an open
question, and I quite understand any scepticism. But a great merit of the
Church-Turing thesis and associated ideas is that it entails a practical
research program of building machines with mental capabilities, which can
yield insight into naturally occuring mental capabilities. I also understand
that many people are upset with what they see as a reduction of humans to
machines, and interpret that as anti-human. A similar thing happened with
Darwin and his apes. But that is the wrong way of looking at it. What has
happened is that our concept of machine has been upgraded, rather than the
concept of what is human downgraded. We can build artificial machines of
much greater causal powers due to the discovery of universal computation and
its embodiment in various computing machines. That means, we as humans, have
progressed. I see no obvious reason why this cannot continue, and therefore
why it will not be possible to entirely replicate our own capabilities in
machines and thereby gain a very deep understanding of ourselves. I'm not
saying that will be easy, or without its surprises along the way.

Clearly I reject the notion that minds possess any non-material or special
properties that could not be understood and replicated by human labour.

Von Neumann, one of the pioneers of computation and computational devices,
wrote a book about self-reproducing automata. He was interested in the
question whether it was possible that a machine could build and construct
other machines of the same or greater computational power. Unfortunately, I
haven't read this book, but it is a good question.

I do not reject psychology, or neuro-psychology, or more contemplative,
philosophical approaches to mind. I think all these approaches can
contribute. However, I do think that they are all ultimately limited because
they are, at root, non-constructive. For example, the human mind, in terms
of density of information processing, is the most complex thing in the known
universe. I think a purely experimental approach of measuring
stimulus-response patterns and deducing underlying mechanisms isn't going to
cut it. Speculative theorising about the mind won't do either. The great
advance of AI has been to take a constructive approach, that is try to build
a material artifact that replicates mental properties.

I don't agree that computational theories of mind cannot explain complex and
contradictory mental processes, such as emotional phenomena. Usually such
theories are causally much richer and more complex than those expressed in
natural language. Another point is that most modern psychology takes the
information processing viewpoint as given, even if not all psychologists
build detailed working computational models, or embodied robots. Finally,
the computational approach is not opposed to the important observation that
the contents of the human mind are constituted by the social environment.

Honestly, there is nothing to fear from this.


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