Page 100 - Foundations of Cognitive Psychology : Core Readings

Minds, Brains, and Programs 101

systems reply simply begs the question by insisting without argument that the
system must understand Chinese.
Furthermore, the systems reply would appear to lead to consequences that
are independently absurd. If we are to conclude that there must be cognition in
me on the grounds that I have a certain sort of input and output and a program
in between, then it looks like all sorts of noncognitive subsystems are going to
turn out to be cognitive. For example, there is a level of description at which
my stomach does information processing, and it instantiates any number of
computer programs, but I take it we do not want to say that it has any under-
standing (cf. Pylyshyn, 1980). But if we accept the systems reply, then it is hard
to see how we avoid saying that stomach, heart, liver, and so on, are all un-
derstanding subsystems, since there is no principled way to distinguish the
motivation for saying the Chinese subsystem understands from saying that the
stomach understands. It is, by the way, not an answer to this point to say that
the Chinese system has information as input and output and the stomach has
food and food products as input and output, since from the point of view of the
agent, from my point of view, there is no information in either the food or the
Chinese—the Chinese is just so many meaningless squiggles. The information
in the Chinese case is solely in the eyes of the programmers and the inter-
preters, and there is nothing to prevent them from treating the input and out-
put of my digestive organs as information if they so desire.
This last point bears on some independent problems in strong AI, and it is
worth digressing for a moment to explain it. If strong AI is to be a branch of
psychology,thenitmust beabletodistinguish thosesystems that are genu-
inely mental from those that are not. It must be able to distinguish the princi-
ples on which the mind works from those on which nonmental systems work;
otherwise it will offer us no explanations of what is specifically mental about
the mental. And the mental–nonmental distinction cannot be just in the eye of
the beholder but it must be intrinsic to the systems; otherwise it would be up to
any beholder to treat people as nonmental and, for example, hurricanes as
mental if he likes. But quite often in the AI literature the distinction is blurred
in ways that would in the long run prove disastrous to the claim that AI is a
cognitive inquiry. McCarthy, for example, writes, ‘‘Machines as simple as ther-
mostats can be said to have beliefs, and having beliefs seems to be a character-
istic of most machines capable of problem solving performance’’ (McCarthy,
1979). Anyone who thinks strong AI has a chance as a theory of the mind ought
to ponder the implications of that remark. We are asked to accept it as a dis-
covery of strong AI that the hunk of metal on the wall that we use to regulate
the temperature has beliefs in exactly the same sense that we, our spouses, and
our children have beliefs, and furthermore that ‘‘most’’ of the other machines in
the room—telephone, tape recorder, adding machine, electric light switch—
also have beliefs in this literal sense. It is not the aim of this article to argue
against McCarthy’s point, so I will simply assert the following without argu-
ment. The study of the mind starts with such facts as that humans have beliefs,
while thermostats, telephones, and adding machines don’t. If you get a theory
that denies this point you have produced a counter example to the theory and
the theory is false. One gets the impression that people in AI who write this