From: chalmers@bronze.ucs.indiana.edu (David Chalmers)
Newsgroups: sci.philosophy.tech
Subject: Re: Dualism
Date: 10 Sep 92 19:52:17 GMT
Organization: Indiana University

In article <29sn2qc@lynx.unm.edu> amiga@phobos.unm.edu (carlos a.f  senaenterr) writes:

>	This is the best argument for dualism that I have come across:
>
>1) What I can imagine is possible.
>2) I can imagine being disembodied.
>3) Therefore, I could be disembodied.

Well, this needs to be fleshed out a lot to turn it into an argument
for dualism.  Minor problems first: (1) can you really imagine
being disembodied?  I don't know if I can -- I literally don't know
what I am imagining.  (2) Even if you can imagine this disembodiment,
would it really be *you* that you are imagining is disembodied?
Or merely someone with a mind qualitatively indistinguishable from
yours?  e.g. it might seem to me that I can imagine myself being
the child of different parents, but really I'm imagining someone
else, just like me.  Being indistinguishable from DC doesn't make
somebody DC.

But these are minor points; for the sake of argument, let's
accept that it's logically possible that you could be disembodied.
Now, how does dualism follow?  It's logically possible that pigs
could fly, but in fact they don't.  On the face of it, your argument
only establishes that dualism is logically possible, not that it's
true.  So at the very least, there is some missing argument.

Personally, I don't think that any strong metaphysical conclusions
can be drawn from the possibility of disembodiment (which is
itself disputable).  However, there is a quite similar argument
that I believe is a good argument for dualism, and probably
a correct one.

(1) It's logically possible that there could be a physical replica
of me without any conscious states.

(2) Therefore the existence of conscious states is a further fact,
over and above the physical facts (i.e. it is contingent relative
to the physical facts).

(3) Therefore dualism is true.

If there's anything wrong with this argument, it has to be at premise
(1).  I confess that this premise seems obviously true to me, but
some people would deny it.  It is contingent on those people to
provide some kind of demonstration of how the physical facts
could possibly logically entail the facts about consciousness,
but such suggestions are usually manifestly unconvincing.  In
virtue of what kind of physical properties is consciousness
logically necessitated?  Suggestions usually revolve around
discrimination of stimuli, or verbal reportability of mental
states, but it seems clear that all those things are logically
compatible with the absence of conscious experience.

(A more rigorous form of this argument would replace premise (1)
by the claim that there's a logically possible world physically
identical to ours, but lacking any conscious experiences.  But
most people accept that the physical facts on which consciousness
supervenes are located within the skin, so it's easier to stick
to the version above, rather than widening the scope to the whole
world.)

-- 
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."