Page 109 - Foundations of Cognitive Psychology : Core Readings

110 John R. Searle

have input and output capabilities that duplicated those of a native Chinese
speaker and still not understand Chinese, regardless of how it was programmed.
The Turing test is typical of the tradition in being unashamedly behavioristic
and operationalistic, and I believe that if AI workers totally repudiated behav-
iorism and operationalism much of the confusion between simulation and du-
plication would be eliminated.
Third, this residual operationalism is joined to a residual form of dualism;
indeed strong AI only makes sense given the dualistic assumption that, where
the mind is concerned, the brain doesn’t matter. In strong AI (and in function-
alism, as well) what matters are programs, and programs are independent of
their realization in machines; indeed, as far as AI is concerned, the same pro-
gram could be realized by an electronic machine, a Cartesian mental substance,
or a Hegelian world spirit. The single most surprising discovery that I have
made in discussing these issues is that many AI workers are quite shocked by
my idea that actual human mental phenomena might be dependent on actual
physical-chemical properties of actual human brains. But if you think about it a
minute you can see that I should not have been surprised; for unless you accept
some form of dualism, the strong AI project hasn’t got a chance. The project is
to reproduce and explain the mental by designing programs, but unless the
mind is not only conceptually but empirically independent of the brain you
couldn’t carry out the project, for the program is completely independent of
any realization. Unless you believe that the mind is separable from the brain
both conceptually and empirically—dualism in a strong form—you cannot
hope to reproduce the mental by writing and running programs since programs
must be independent of brains or any other particular forms of instantiation. If
mental operations consist in computational operations on formal symbols, then
it follows that they have no interesting connection with the brain; the only
connection would be that the brain just happens to be one of the indefinitely
many types of machines capable of instantiating the program. This form of
dualism is not the traditional Cartesian variety that claims there are two sorts
of substances, but it is Cartesian in the sense that it insists that what is specifi-
cally mental about the mind has no intrinsic connection with the actual prop-
erties of the brain. This underlying dualism is masked from us by the fact that
AI literature contains frequent fulminations against ‘‘dualism’’; what the au-
thors seem to be unaware of is that their position presupposes a strong version
of dualism.
‘‘Could a machine think?’’ My own view is that only a machine could think,
and indeed only very special kinds of machines, namely brains and machines
that had the same causal powers as brains. And that is the main reason strong
AI has had little to tell us about thinking, since it has nothing to tell us about
machines. By its own definition, it is about programs, and programs are not
machines. Whatever else intentionality is, it is a biological phenomenon, and it
is as likely to be as causally dependent on the specific biochemistry of its ori-
gins as lactation, photosynthesis, or any other biological phenomena. No one
would suppose that we could produce milk and sugar by running a computer
simulation of the formal sequences in lactation and photosynthesis, but where
the mind is concerned many people are willing to believe in such a miracle be-
cause of a deep and abiding dualism: the mind they suppose is a matter of for-