From: wgns@troi.cc.rochester.edu (C. Wiggins)
Newsgroups: sci.philosophy.tech
Subject: Re: Dualism
Date: 10 Sep 92 05:22:30 GMT
Organization: University of Rochester - Rochester, New York

In <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 argument is a very simplifed version of what I, too, take to be a
pretty strong argument for dualism.  
I believe that Kripke was responsible for it's most precise version, but the
one abocaptures the main idea well enough.  The original poster wanted 
some reasons to think the argument fails, so here are some to consider and
evaluate:

Consider premise (1).  If you have the relevant sense of possibility in mind,
it will seem quite plausible.  But is it true?  Are there counterexamples?  
Here are some possible ones:

(1)  Is it possible for me to conceive of a right triangle about which it is not
	the case that (A*A)+(B*B)=(C*C)?  If this is conceivable, then (1) is
	false (since such a triangle is NOT possible).  One can think of other
	examples from mathematics -- take any complicated equation, and ask
	yourself if you can conceive of the left half not being equal to the
	right, etc.

Possible Reply:

	Any "ability" to conceive of such things is merely apparent.  A dualist
	might argue that these aren't genuine cases of conceivability -- only
	apparent ones.  If one REALLY, fully understands what one is trying to
	conceive of in those cases, one will find she just can't do it.

(2)  The morning star (which used to be called Hesperus), and the evening star
	(which used to be called Phosophorus), are one in the same object --
	namely planet Venus.  This is a fact that wasn't always known.  Now
	consider some guy, Joe, who lived in a time before this fact was     
	discovreed.  Joe not only could conceive of Hesperus being non identical
	to Phosphorus, he actually BELIEVED they weren't identical.  But of 
	course given that Hesperus=Phosphorus, it is impossible for what he
	is conceiving of to be the case.  Thus (1) is false.

In this example, it seems to me, it's a bit harder to just deny that the     
conception in question is really merely apparent.  And since it's not possible
for Hesperus to not be identical to Phosphorus, this conception is a        
counterexample to (1), it seems.  But suppose that though hard to believe, 
Joe really wasn't conceiving of Hespherus being nonidentical to Phosphorous.
Well, then, isn't that a reason to doubt premise (2)?  After all, it seems
(at least to many people) VERY intuitively plasible to say that Joe was really
conceiving of something impossible.  If we're wrong about that, couldn't we
be wrong when we think that we can conceive of ourselves existing without our
bodies?  If Joe was wrong, a materialist might argue, it seems that we can't
trust our intuitions when we think we can conceive of something.      

I hope that gives you something to consider, anyway.  It's an interesting
argument, and I don't pretend to be decicively refuting it here.  But I
hope the above considerations aid you in your evaluation of it.

Chris Wiggins
Department of Philosophy
University of Rochester
Newsgroups: sci.philosophy.tech