THE TIMES HIGHER EDUCATION SUPPLEMENT 17 MAY 96 Page 27
BOOKS PSYCHOLOGY & PSYCHIATRY
We have the technology . . .
BY JOCELYN PAINE
COGNITIVE CARPENTRY: A
BLUEPRINT FOR HOW TO BUILD A PERSON
BY JOHN L . POLLOCK
MIT Press 377pp. £29 50
ARTIFICIAL MINDS
BY STAN FRANKLIN
MIT Press. 449pp £22.95
Train sets, Meccano, Sim City: I've always liked to build working models.
And a working model of mind has a special fascination. This is surely sufficient
reason for doing Al: but I can also feel a glow of satisfaction at knowing
I am helping my neighbouring disciplines survive.
As John Pollock says in Cognitive Carpentry, philosophy needs Al as much
as Al needs philosophy. One necessary test of a theory of mind is that we
can build an Al system which implements the theory. It behooves philosophers
to remember this, for many popular philosophical theories are not implementable.
...
...
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In contrast to Cognitive Carpentry, Franklin's Artificial Minds is written
for the nonspecialist; billed as an informal tour of some artificial "mechanisms
of mind" and of three Al debates. The diversity of Al would challenge
any writer: two major paradigms, symbolic Al and connectionism. and several
minor ones, all home to a variety of techniques and approaches. Symbolic
Al is based on the theory that we think by manipulating mental symbols (standing
for objects, events, etc.) according to explicit rules. This is sufficient
to explain human intelligence (and, as with Oscar. to make a machine behave
intelligently; our explanations do not need to descend to the level of the
brain's neural hardware, any more than a programmer need explain his program
in terms of logic gates. Connectionist models go deeper. imitating how our
neurons operate
Though the paradigms differ greatly. they usually stand together in their
emphasis on modeling isolated mental functions. Some critics argue that
we should instead try to understand the whole organism, starting with simple
agents like insects. The point is- think of Oscar's practical cognition-that
real minds evolved to survive in a complex environment by producing the
next action. Our mental functions originated subservient to this end, so
this is the context within which we must place our models. Broadly speaking,
this is the artificial life or situated agents approach.
Franklin promotes a combination of this "action selection" view
with another which-following Marvin Minsky's Society of Mind and the rise
of distributed computing-is increasing in popularity, namely, that mind
is not a hierarchical system overseen by a global controller, but a collection
of autonomous modules each devoted to a specialized task. So, although he
describes one symbolic Al program, Soar (one of a few programs claimed to
embody a unified theory of cognition), and some examples of conectionism.
as well as the debate between the two, he gives more attention to artificial
life and multiple agents research. including Wilson's Animat (a creature.
which evolves rules about how to find food) and Pattie Maes's behavior networks.
He also describes Pentti Kanerva's nifty model of sparse distributed memory.
and Hofstadter and Mitchell's excellent Copycat analogical reasoner.
These originated mostly between 1985 and 1991. It is good to see a popular
writer who does not feel obliged to recapitulate a science's entire development,
thus forcing himself to squeeze the quarks and quasars into his final chapter's
last few pages. That said, pointers to other popular accounts would help
the reader obtain a balanced view. Franklin gives a nice survey of recent
work for the general reader, though some of his program descriptions are
unclear. More examples would help. Textbooks tend to omit the topics he
covers, so Artificial Minds would also interest students.
Jocelyn Paine teaches artificial intelligence in the department of experimental
psychology, University of Oxford.