Strong AI is (according to
Searle) the following three theses conjoined:
I. Mind as Program --
"Minds" are simply very complex computer programs. Any system which had the
right program, and the right input and output would have mental processes just like us.
II. The Irrelevance of the
Neurophysiology of the Brain -- While the brain is necessary for you and I to think,
it is not necessary for "thinking" per se. If the mind is just a program, then
if some entity without a brain could nonetheless "run" that program, it could
think. The brain is just one kind of thing that can run the right program.
III. The Turing Test Criterion of the
Mental -- "If a system can convince a competent expert that it has mental states
then it really has those mental states."
Here is Searle's argument in
1. Brain processes cause mental phenomena.
(statement of fact)
2. Any system that produces mental
phenomena must have powers equivalent to those of the brain. (inference from 1)
3. Digital computer programs by themselves
are never sufficient to produce mental phenomena. (Chinese Room analogy.
4. Therefore, the brain does not produce
mental phenomena simply by instantiating some digital computer program.
MAIN POINTS FOR SEARLE:
1. Defenders of Strong AI
miss distinction between simulation and duplication (i.e. computers can simulate a
tornado, thirst, etc., but that's different from duplicating it.)
2. Computers have syntax but
no semantics -- they know how to organize and manipulate symbols, but they CANNOT attach
meaning to those symbols.