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

From: Ian Wright (ian_paul_wright@HOTMAIL.COM)
Date: Mon Jan 19 2004 - 15:02:24 EST

Jerry wrote:

>The Church-Turing thesis, evidently, assumes that all human mental
>activity is expressed through formal logic.  This is a very dubious
>(btw, will machine dialogue at some point in time replace OPE-L and
>other forums for the discussion of political economy, Ian?)

I think we are machines, ultimtately built by a more encompassing process of
induction, which is evolution. So I think machines are already discussing
political economy.

The crux of the question is what is meant by "machine". I do not have a 19th
centrury machine metaphor in mind, in which systems are composed of
mechanical relations. The human mind is not like that. Instead I have a
modern metaphor in mind, one inspired by the computer, that considers that
minds are semantic information processors. The discipline of trying to build
mind-like artifacts has taught us a lot about how it is possible that minds
operate in material terms.

So by "machine" all I am really saying is that the mind is a natural object
that in principle can be  understood by science, and that some of our
current artificial machines have mental properties, albeit of a simple kind.
The best hypothesis of how minds work is the computational approach, as
unlike previous approaches it is both more explanatory and has practical
consequences, such as the ability to automate mental operations.

The Church-Turing thesis doesn't assume that minds work according to the
principles of formal logic, or at least the field of AI does not make that
assumption. Formal logical systems, of which there has been an enormous
proliferation of types, do have their uses when building robots, but are
useless for controlling effectors to move around, catch balls and the like.
What engineers have found is that to build mind-like control systems
requires a whole range of mechanisms and representations, from quick,
fast-acting feedback loops, to statistical inference mechanisms,
pattern-matching, and at levels less tightly-coupled to the physical world,
logical and symbolic deductive mechanisms, such as kinds of formal logics.
The point is, however, that all these kinds of mechanisms are implementable
on a Universal Turing Machine.

Sorry to get off topic. This is not exactly political economy! But to be a
little cheeky I'll claim that any theory of a dialectical logic worth its
salt should be able to be formalised and implemented on a computer. The
problem in general with philosophies is they don't run. So they're hard to


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