* What problems are computable?
then the basic question of artificial intelligence (AI) is:
* Is "intelligence"/cognition/thinking computable?
(where by "intelligence" I am not necessarily referring to whatever it is that is alleged to be measured by IQ tests, but simply the kinds of mental abilities that cognitive psychologists study: what they call "cognition", and what most people call "thinking").
b) Given our definitions of "computable" and "algorithm", the basic question of AI becomes:
* Is there an algorithm (or a collection of them) that computes (human) cognitive processes?
c) AI is the branch of computer science that investigates this question.
"[AI is] the science of making machines do things that would require intelligence if done by humans."
* Note that this uses humans to tell us how to program computers.
b) According to Margaret Boden, a psychologist,
"[AI is] the use of computer programs and programming techniques to cast light on the principles of intelligence in general and human thought in particular."
* Note that this uses computers to tell us something about humans. (Just as, in other sciences, theories are expressed in the languages of English, or mathematics, or statistics, so, in AI, theories about cognition can be expressed in the languages of computer programs.)
c) In fact, AI is both of the above, a 2-way street.
If (human) cognitive processes can be expressed as algorithms,
then they are capable of being implemented in
(non-human) computers.
So:
Are computers executing such algorithms merely simulating cognitive processes, or are they actually exhibiting them?
One answer was given by Alan Turing's "Turing Test".
An objection to that answer was given by
John
Searle's "Chinese-Room
Argument"
Turing, Alan M. (1950),
``Computing
Machinery and Intelligence'',
Mind 59: 433-460.
b) For a description of the Turing Test, together
with a description of the Chinese-Room
Argument, and my own views on them,
see:
Rapaport, William J.
(2000),
"How
to Pass a Turing Test: Syntactic Semantics, Natural-Language Understanding,
and First-Person Cognition",
Special Issue on Alan Turing and Artificial Intelligence,
Journal of
Logic, Language, and Information
9(4):
467-490.
c) Briefly, the Turing Test considers an interrogator
and either a human or a computer
(the interrogator doesn't know which) in a room;
the interrogator's job is
to ask questions of
whoever or whatever is in
the room to see if
it can be determined whether
it's a human or
a computer.
d) Turing wrote (in 1950):
"I believe that at the end
of the century
the use of words and general educated
opinion will have altered so much that
one will be able to speak of machines thinking
without expecting to be contradicted"
* Note
that it is now (Dec. 6, 2000, as I write) the
"end of the century"!
e) 2 questions:
* How would
you program a computer to pass the Turing test?
* What
kinds of questions should the interrogator ask?
I have prepared an AIQ
test that you might find interesting.
Suppose that the interrogator is a native speaker
of Chinese.
Suppose that there is a human in the other room
who does not understand either spoken or written
Chinese.
Suppose that the human in the room is equipped
with a book that contains an algorithm, written in
English (which the human does understand), that
tells the human how to manipulate certain "squiggles"
(actually, Chinese characters) in certain ways.
Suppose that the interrogator gives to the human
in the room a story in Chinese, followed by a series
of questions about the story, also in Chinese.
Suppose that the human takes this input, which, to
him (I say "him", because in the original version of
the argument, the person in the room is Searle) is
nothing but meaningless squiggles, manipulates the
squiggles according to the algorithm, and outputs
more squiggles.
To the interrogator standing outside the room,
the output consists of perfectly grammatical
and correct answers in Chinese to the questions.
So, from the interrogator's point of view, the man
in the room has passed a Turing test for
understanding Chinese, but from the point of view
of the man in the room, he does not understand
Chinese.
Therefore, the Turing Test fails as a test of
a computer's ability to "understand" or exhibit
real cognition.
I will leave as a final exercise for the reader the
answer to the question whether cognition is
computable.
(For the record, I think it is. For my reasons,
see my paper on the Turing Test, cited above,
and:
Rapaport, William J. (1998),
"How
Minds Can Be Computational Systems",
Journal of Experimental and Theoretical Artificial Intelligence
10: 403-419
4. The Turing Test
a) For Turing's original paper, see:
5. An Artificial IQ Test
One way to begin to answer that last question is to
consider the kinds of questions that are found on
"IQ" or SAT-type tests.
6. The Chinese-Room Argument
Searle's objection to the Turing Test is that it is
possible to pass the TT, yet not (really) think.
7. For More Information on AI, See:
SOME
STANDARD SOURCES OF INFORMATION ON A.I.