6-30 People can be mistaken about their experiences.
. . . is disputed by . . .
6-31 Rational cognitive systems have correct beliefs.
The claim (David Chalmers, 1996)
Subjects who are radically mistaken about their experiences are
not rational. Rational systems (systems whose cognitive mechanisms
are unimpaired) will not make enormous errors about their own
conscious experiences. Even if an individual's neurons have been
replaced by silicon chips, that person should still be rational,
and thereby have (at least, mostly) correct beliefs and make correct
statements about his or her conscious experiences.
A rational system whose cognitive mechanisms are unimpaired will not make massive errors about it's own conscious experiences. A system with part of its neurons replace by silicon chips (that are functionally equivalent) will still be rational and cognitively unimpaired. Therefore, it will have correct beliefs. The only way it can have correct beliefs about its own experiences is if it still actually has conscious experiences.
The Chalmers argument
David Chalmers describes this claim as follows: "In these
cases, however, we are no longer dealing with fully rational systems.
in systems whose belief formation mechanisms are impaired, anything
goes. Such systems might believe that they are Napoleon, or that
the moon is pink. My "faded" isomorph Joe, by contrast,
is a fully rational system, whose cognitive mechanisms are functioning
just as well as mine. In conversation, he seems perfectly sensible.
We cannot point to any unusually poor inferential connections
between his beliefs, or any systematic psychiatric disorder that
is leading his thought processes to be biased toward faulty reasoning.
Joe is an eminently thoughtful, reasonable person, who exhibits
none of the confabulatory symptoms of those with blindness denial.
The cases are therefore disanalogous. The plausible claim is not
that no system can be massively mistaken about its experiences,
but that no rational system whose cognitive mechanisms are unimpaired
can be so mistaken. Joe is certainly a rational system whose mechanisms
are working as well as mine, so the argument is unaffected"
(D. Chalmers, 1996, p. 261).
References
Chalmers, David. 1996. The Conscious Mind. New York: Oxford
University Press.