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From: smoliar@vaxa.isi.edu (Stephen Smoliar)
Newsgroups: comp.ai
Subject: Re: The Success of AI (Analysis of AI lack of progress).
Message-ID: <3852@venera.isi.edu>
Date: Tue, 20-Oct-87 12:04:07 EDT
Article-I.D.: venera.3852
Posted: Tue Oct 20 12:04:07 1987
Date-Received: Sat, 24-Oct-87 16:01:27 EDT
References: <1922@gryphon.CTS.COM> <5505@jade.BERKELEY.EDU>
Sender: daemon@venera.isi.edu
Reply-To: smoliar@vaxa.isi.edu.UUCP (Stephen Smoliar)
Organization: Information Sciences Institute
Lines: 95
Keywords: Philosophy of mind, Rationalist tradition.


Those who would like a taste of the Dreyfus style before embarking upon one of
his books in its entirely would do well to consult the Summer 1986 issue of
IEEE EXPERT.  The article "Why Expert Systems Do Not Exhibit Expertise,"
by Hubert and Stuart Dreyfus, is an excerpt from MIND OVER MACHINE:  THE
POWER OF HUMAN INTUITION AND EXPERTISE IN THE ERA OF THE COMPUTER.  While
there is definitely merit to deflating exaggerated claims about expert systems
which have been made in the name of salesmanship, Hubert Dreyfus approaches
this issue as a philosopher.  Consequently, the technical baggage he carries
is often not particularly timely and often inadequate.  Were he to wage his
campaign on the battelground of the philosophy of mind, he might come away
with some notable victories;  but by descending to the level of technology,
he often falls into traps of misconception.

Here is a sample passage:

	Humans often think by forming images and comparing them
	holistically.  This process is quite different from the
	logical, step-by-step operations that logic machines
	perform.

There are several things wrong here.  First of all, a holistic theory of
memory or reasoning remains a HYPOTHESIS.  Claiming it as an observation
is a gross misrepresentation of the surrent state of cognitive science.
Second, the term "logic machine" has been introduced to capture a particular
machine architecture which lacks what Dreyfus wants it to lack.  He does
not admit of the possibility of an alternative architecture for the
mechanization of thought which could model the holistic hypothesis.
Fortunately, more productive cognitive scientists HAVE pursued this
line of reasoning.

In any event, the text continues in an attempt to elaborate upon this point:

	For instance, human beings use images to predict how certain
	events will turn out.

This is, again, hypothesis.  It rests on a weaker hypothsis which is never
cited:  that human beings use MODELS to predict how certain events will
turn out.  This is the whole "mental models" approach to cognition, for
which there is both subtantial literature and experiments in mechanical
implementation.

The text continues:

	Programming a computer to analyze a scene has turned out to
	be very difficult.  Such programs require a great deal of
	computation, and they work only in special cases with objects
	whose characteristics the computer has been programmed to
	recognize in advance.

Nevertheless, such programs may work better than people in those special
cases and can be used in factories.  That is why industrial robotics has
become as effective as it has.  I regard this as an instance of the situation
I raised regarding perpetual motion machines in an earlier note.  I raised
the point that had Bessler's machine actually been put to work and found
to run for significantly long periods of time without energy input, it
would have been an impressive contribution even if its energy dissapated
very slowly, rather than not at all.  Similarly, we would do better to
study special cases of scene analysis which are successes rather than
belabor the obstacles to a more general approach to the task.

It gets better:

	But that is just the beginning of the problem.  Computers
	currently can make inferences only from lists of facts.
	It's as if to read a newspaper you had to spell out each
	word, find its meaning in the dictionary and diagram every
	sentence.

This strikes me as a gross misrepresentation of mechanical reasoning, and
I think the crux of this misrepresentation is a confusion between reasoning
and representation.  Fortunately, there are other philosophers who appreciate
that these are distinct issues;  but they don't seem to attract as much
attention as Dreyfus.

One last jab in parting:

	However, a computer cannot recognize emotions such as anger
	in facial expressions, because we know of no way to break
	down anger into elementary symbols.  Therefore, logic machines
	cannot see the similarity between two faces that are angry.
	Yet human beings can discern the similarly almost instantly.

This strikes me as another example of sloppy thinking.  Are we talking
about a GEDANKEN experiment here?  If so, how are we to define it?
Are we looking at faces out of context in an attempt to infer emotion?
If so, then I would claim that humans are nowhere near as good as is
claimed.  Indeed, man has been notorious for misreading emotion.  The
lack of this skill has probably perpetrated many major historical events.
Seymour Papert used to accuse Dreyfus of committing the "superhuman human"
fallacy by assuming that an artrificial intelligence would surpass a human
one.  Here is a situation where Dreyfus hasd gone out on a limb which he
should have left alone.  Our understanding of how PEOPLE exhibit and
perceive emotion is sufficiently weak that, for the most part, artificial
intelligence seems to have to good sense to leave it in peace.