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>From: chalmers@bronze.ucs.indiana.edu (David Chalmers)
Subject: Re: Causes and Reasons
Message-ID: <1991Dec23.210052.25960@bronze.ucs.indiana.edu>
Keywords: intensionality, agency, causation, syntax, semantics, pragmatics
Organization: Indiana University
References: <1991Dec19.133719.22212@oracorp.com> <1991Dec23.041134.6879@husc3.harvard.edu>
Date: Mon, 23 Dec 91 21:00:52 GMT
Lines: 38

In article <1991Dec23.041134.6879@husc3.harvard.edu> zeleny@zariski.harvard.edu (Mikhail Zeleny) writes:

>You might have noticed that Chalmers has wisely chosen to abstain from
>maintaining his ridiculous claims about the causal powers of programs.

Only because the point was made, and there's no need to beat it to death.
Your last post on the subject demonstrated a sufficiently gross
misunderstanding of the notions of supervenience and implementation
that there was little point in continuing the discussion.

>Look Daryl, I don't know how to explain this any clearer.  Once again, the
>logical structure of the world is less finely differentiated than its
>physical, causal structure, or even its mathematical structure, as
>evidenced by the failure of logicism; which is to say that mathematics,
>and, a fortiori, physics, introduce more assumptions about the world than
>does logic alone.  So the logical structure of a program cannot, in and of
>itself, induce a physical, causal structure of its execution by a computer;
>it takes extra constraining to achieve this effect, and insofar as it
>involves interpretation, the job of furnishing the extra constraints is
>essentially creative.

For the last time: *of course* logical structure isn't sufficient for
causal structure.  That's why we need the notion of implementation.
Implementation is a *relation* between syntactic structures (programs)
and physical systems; and by the very meaning of the term, a physical
system only implements a given program if it has the right causal
structure.

>From this post and others, it appears that your problem is a conflation
of the notions of implementation (of a program in a physical system)
and interpretation (of a formal system in a model).  Big mistake. The
model-theoretic problems with interpretation are simply irrelevant to
implementation.

-- 
Dave Chalmers                            (dave@cogsci.indiana.edu)      
Center for Research on Concepts and Cognition, Indiana University.
"It is not the least charm of a theory that it is refutable."


