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From: kp@uts.amdahl.com (Ken Presting)
Newsgroups: comp.ai,talk.philosophy.misc,sci.philosophy.tech
Subject: Re: Can Machines Think?
Message-ID: <2c0R02gv76O601@amdahl.uts.amdahl.com>
Date: 19 Dec 89 21:46:41 GMT
References: <31821@iuvax.cs.indiana.edu> <6724@cbnewsh.ATT.COM>
Reply-To: kp@amdahl.uts.amdahl.com (Ken Presting)
Organization: Amdahl Corporation, Sunnyvale CA
Lines: 36

In article <6724@cbnewsh.ATT.COM> mbb@cbnewsh.ATT.COM (martin.b.brilliant) writes:
>From article <31821@iuvax.cs.indiana.edu>, by dave@cogsci.indiana.edu
>(David Chalmers)...
>
>  1. Systems with an appropriate causal structure think.
>  2. Programs are a way of formally specifying causal structures.
>  3. Physical systems implement programs.
>  4. Physical systems which implement the appropriate program think.
>
>I take it that (1) is an acceptable definition.  Does anybody think it
>begs the question?

I don't think so.  Presumably, humans think because of the way we're
built, and the mechanical/chemical/electrical structure determines the
causal structure of our brains.

>The weakest link here may be (2), the supposition that programs can
>implement any causal structure whatever, even those that do what we
>call thinking.

Agreed.  The multi-body problem of astrophysics is a clear case of a
causal system which cannot be precisely represented by an algorithm.
But the argument could succeed with a weaker version of 2, IF we could
figure out which causal structures are relevant to thought

>The software/hardware duality question is semantically resolved by (3).

This is problematic.  Harnad's "symbol grounding problem" (and some of
Searle's objections, I think) point out the difficulty of claiming that
some object "thinks" strictly on the basis of its internal operation,
or even on the basis of it's outputs.  Harnad would want to know how the
symbols found in the output are grounded, while Searle might claim that
the machine *simulated* thinking, but did not itself *think*.
  I agree that the correct resolution of the software/hardware duality
can only be resolved by the concept of implementation used in (3).  I'm
just repeating a familiar (but important) theme.