From: chalmers@bronze.ucs.indiana.edu (David Chalmers)
Subject: Re: Dualism
Organization: Indiana University
Date: Wed, 30 Sep 1992 02:12:36 GMT

In article <1992Sep29.130441.29896@sophia.smith.edu> orourke@sophia.smith.edu (Joseph O'Rourke) writes:

>Despite your rejection of evolution, I believe it can give a type
>of answer to both.  We feel because it is evolutionarily advantageous
>to experience pain, to have our pulse quicken at sharp sounds, etc.
>And perhaps it is neurologically most efficient for these survival
>advantages to be implemented via experiential feel, rather than
>zombie reactions.

The trouble with this is that is simply doesn't touch the main
question.  Everybody -- i.e. the physicalist and I -- are agreed
that evolution selects physical structures, based on their
functional roles.  i.e., it will select a certain sort of brain
organization, with certain patterns of neural connectivity that
lead to advantageous consequences, and the like.  The question
here, however is: why, given that the brain structure and function
is like so, do we have qualia (and why are the qualia the way
they are?).  As I said earlier, evolution doesn't have anything
to say to this.

It seems coherent that precisely the same functions could have been
performed by a physically identical zombie.  Evolution can't tell
the difference between the zombie and me.  To get around this
argument, the physicalist will simply have to deny that the
physically identical zombie is logically possible.  And that denial
is a separate issue (which we've been arguing for a while), quite
independent of the questions about evolution.

>	Why this rather than that may again answer to what is
>most advantageous and most efficient:  there is some sense to
>experiencing blue as darker than red, since it *is* darker;
>so inverting blue and red might weaken other cues of the experiential
>feel, other uses.  So perhaps inverted spectra are perfectly possible,
>but just not a wise use of neurological resources.

Again, the advantage accrues to the functional role, not to the
experience per se.  So this explanation has nothing to say about
why that functional role has to be accompanied by the experience.

>	If explanations along these lines do not satisfy you, then
>it seems you seek a finer neurochemical understanding of why
>opiates make us feel good, why epinephrine heightens awareness, and
>so on.  Surely this type of micro-understanding of our brain processes
>is on the way.

An explanation of the brain will tell us why certain functional
processes take place within us, and affect our reactions in certain
ways.  This doesn't tell us anything about the main question, which
is, as always: why are these processes accompanied by qualia?

>	If even these explanations would not satisfy you, then
>perhaps you could make clear what type of explanation *would* satisfy you.

Obviously, I'm not sure that there *can* be a good physicalist
explanation of qualia, which is why I lean toward dualism.  A
dualist explanation of qualia will take the existence of qualia as
a further irreducible property of the way the world is, and so
won't "explain" their existence any more than physics "explains"
why matter exists, or why the law of gravity is true -- some things
have to be taken as basic and brute facts.  Of course, once that
step is taken, the dualist can seek to systematize those facts, and
in particular to investigate the possibility of a set of systematic
and parsimonious laws connecting qualia with the physical (e.g.,
taking qualia to be intimately linked with information).

That way of proceeding isn't open to the physicalist, however, who
can't admit qualia as basic.  On the physicalist view, they must
follow from prior physical facts about the universe (such as the
facts given to us by physics).  A physicalist explanation must show
why, given the physical facts about the brain, the existence of
qualia is *inevitable* -- why it simply couldn't be any other way.

-- 
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."
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