From newshub.ccs.yorku.ca!ists!helios.physics.utoronto.ca!news-server.ecf!utgpu!cs.utexas.edu!sun-barr!olivea!spool.mu.edu!sol.ctr.columbia.edu!bronze!chalmers Mon Mar  9 18:33:28 EST 1992
Article 4100 of comp.ai.philosophy:
Path: newshub.ccs.yorku.ca!ists!helios.physics.utoronto.ca!news-server.ecf!utgpu!cs.utexas.edu!sun-barr!olivea!spool.mu.edu!sol.ctr.columbia.edu!bronze!chalmers
>From: chalmers@bronze.ucs.indiana.edu (David Chalmers)
Newsgroups: comp.ai.philosophy
Subject: Re: Virtual Person?
Message-ID: <1992Feb27.230406.15053@bronze.ucs.indiana.edu>
Date: 27 Feb 92 23:04:06 GMT
References: <9202181833.AA12222@ucbvax.Berkeley.EDU>
Organization: Indiana University
Lines: 46

In article <9202181833.AA12222@ucbvax.Berkeley.EDU> GUNTHER@WMAVM7.VNET.IBM.COM ("Mike Gunther") writes:

>During neuron replacement I can imagine the qualia dropping out
>suddenly, once a threshold is reached, with no effect on behavior.
>The simulation takes over to just such an extent as to compensate for
>the loss of the real thing.  It is less strain on my imagination
>if the qualia are lost all at once, but I think it's also possible
>that the qualia fade.  The person might subjectively see pink, but
>would still report red (cf. the inverted spectrum argument) because
>the functional connection between red-frequency light and the spoken
>word "red" has been maintained.  And I think that one could argue
>that the simulation would also remove awareness of difference.  If
>the subject tried to remember what red used to look like, the memory
>would come out subjectively pink and therefore the subject would not
>notice the change.

There's more going on here than simple spectrum inversion.  In
spectrum inversion, one's qualia change, but relations of similarity
and difference between qualia stay fixed, because the relations between
qualia have to cohere with corresponding functional properties.  e.g. a
case where both before and after spectrum inversion, a person is presented
with the same pair of different stimuli.  Both times, the person says
"those look like very different colours", and so both times, the
person experiences a pair of very different qualia (though different
pairs in each case, of course).  The point is that properties of
the qualia-space have to cohere strongly with functional properties,
even if they're not reducible to them.

But in the fading qualia case, at some stage the properties of the qualia
must start to decohere from the functional properties (this follows from
the fact that at one extreme, there is complete coherence, and at the
other end, there is no coherence).  Somewhere along the line, the person
will be saying "those are very different qualia", even when the qualia
experienced are all but identical; they will be saying "that's a very
bright light", and recoiling, even though they're experiencing only
faint qualia, and so on.  So these people will be simply *wrong* about
their qualia.  And this seems to be implausible.  Whie it might just be
reasonable to suppose that a qualia-less creatures could go around making
false utterances about having qualia, it does not seem reasonable that
a being that actually has qualia could be so systematically mistaken
in the things they say and believe about their experiences.

-- 
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."


