Re: AI & HPCT
From Tom Bourbon [ 920604 -- 9:20 ]
[ From Ray Allis 920603.1100 ]
in a response to Bill Powers (920603.0730)
Note that a model is an analog, existing in the real world,
affected by the real world, in ways not necessarily predicted/able
by the modeler. e.g. a wind tunnel model may reveal some effects
which are a surprise.
A simulation, being a construction of logical statements, is
unaffected by events in the physical world. It is totally
deductive; its states are absolutely determined by its form.
There are no surprises. A simulation can be made to disclose all
its implications, but no more than were built into the starting
construction. ...
I hope I didn't bore you all too much, but it's been bothering me
that "model" and "simulation" are used pretty much interchangeably
in some of the discussions, and I see that as one of the reasons
AI is such a total failure. I just HAD to say it.
Ray, you certainly were not boring and you need not apologize
for your remarks about the meanings of "model" and "simulation"!
The issue you address is an important one and PCT modelers must be
careful that others understand what we mean by those terms.
I think the way PCT modelers use the terms avoids the mistakes
you identify in traditional AI. A PCT model IS an analog -- we
assume that the program statements in a PCT model are analogs of
the functional organization of a living system AND OF ITS
ENVIRONMENT. The phrase in caps is crucial. At the very minimum,
there are TWO system equations in a PCT model, one to characterize
interactions among functions and variables in the environment, some
of which may vary independently of any actions by the control
system, and one to characterize the assumed functions and signals
internal to the control system. The "running" of the model is a
simulation of the moment-by-moment interaction of the PCT model AND
its environment. -- the iterative solution of the system
equations, with new and often unpredictable values of environmental
variables inserted from simulated moment to simulated moment. When
a PCT model, or any other model, is simulated in this fashion,
there are OFTEN surprises -- some very pleasing to the modeler,
others very unsettling. From my own experience, the first time I
simulate the PCT model in a new environment is a lot like the times
when my children were small and I watched them try a new skill, or
perform in public -- I knew, in principle, what SHOULD happen ....
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From: "Allan F. Randall" <randall@DRETOR.DCIEM.DND.CA>
Subject: Re: AI & HPCT
There is something I don't understand. I'm new to this list, and
have been noticing a rather strong opposition to "AI" as opposed
to "HPCT". I'm not sure I understand the distinction that's being
made. Why is HPCT not AI? When you program a little man or some
other control system and claim to be studying perception, then as
far as I am concerned, you are doing AI, ...
... I guess the question I'm trying to ask here is this: "Might an
intelligent robot someday be built using control theory
principles?" If the answer is yes then HPCT is part of AI.
Allan, if everyone who is interested in AI were as encouraging
and tolerant as you, the appearance of opposition and militancy
that you detect on CSG-L would vanish! No matter how politely and
innocently a PCT modeler presents the case for PCT, most advocates
of AI who bother to respond claim that PCT is "old hat," as Rick
Marken recently pointed out, but most of them simply ignore PCT.
In that regard, the reactions to PCT by proponents of orthodox AI
are similar to those by most other behavioral and cognitive
scientists, whatever their theoretical labels.
On the other hand, I believe most advocates of PCT would agree
with your conviction that the control-theoretic model IS a model of
systems that behave intelligently. In that sense, the PCT model IS
a form of artificial intelligence, but by the lights that guide the
AI community, PCT is not part of, Artificial Intelligence: The
Movement.
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Best wishes to all --