From: chalmers@bronze.ucs.indiana.edu (David Chalmers)
Newsgroups: sci.philosophy.tech
Subject: Re: Dualism
Date: 13 Oct 92 21:50:09 GMT
Article-I.D.: usenet.Bw2xzL.GIA
Organization: Indiana University

In article <1992Oct13.191235.17667@guinness.idbsu.edu> holmes@opal.idbsu.edu (Randall Holmes) writes:

>Chalmers is working in a scheme of modal logic in which two things
>which are possibly different are necessarily different.  The fallacy
>in his argument is that he _cannot_ prove that qualia are different
>from certain physical events by claiming that there is a possible
>world in which they are different; he cannot build that possible world
>without covertly assuming the difference he is trying to prove.

No, that's not the way the argument runs.  I've pointed that out on
a number of occasions -- there's no such inference from possibility
of non-identity to non-identity.  In fact, identity plays no role
in the argument at all.  The argument concerns supervenience.  It's
disappointing to see you putting forward the same old canard.

>If consciousness = relevant physical events in this world, then the
>equation holds in all possible worlds, in the scheme of modal logic
>which Chalmers is using.  The point is that "it seems possible for
>there to be a zombie replica of myself" does not use the word
>"possible" in the techincal sense required to say that there is a
>possible world in which this is the case.  It means something like
>"imaginable", and the logic of "imaginable" is a little different. 

I've been over all this, too.  Whichever way you run the modal logic,
the argument goes through fine.  Whether you want to use "technical"
(Kripkean a posteriori) possibility or "non-technical" (conceptual
coherence) possibility, the argument goes through.

>I can imagine worlds with vital forces, phlogiston, caloric, and
>non-physical qualia just as well as Mr. Chalmers.  Moreover, there are
>possible worlds in the technical sense in which it would make sense to
>talk about these things.  But the "non-physical qualia" in such a
>possible world would not correspond to the actual (physical) qualia in
>this world if qualia = physical events holds, and such an argument
>cannot prove the impossibility of the equation.

For the umpteenth time, the possibility of non-physical qualia plays
*no* (repeat: *no*) role in the argument.  As I stated a long long
time ago, arguments from the possibility of non-physical qualia
prove nothing, for the sorts of reasons you mention.  The argument
I've made is from the possibility (even the coherent imaginability,
if you like) of a zombie world -- the physics without the qualia,
not vice versa.  If this world is even a coherent notion, then I'm done
done, as it shows that the physics doesn't exhaust the way the world
is -- after making the physics, God still had more work to do.

Anyway, I'm not really interested in resurrecting this discussion, but
if you're going to discuss the argument, please make sure that it's
the right argument that you're discussing, rather than putting words
into my mouth.

-- 
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."
Newsgroups: sci.philosophy.tech