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Article 6797 of comp.ai.philosophy:
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>From: harnad@phoenix.Princeton.EDU (Stevan Harnad)
Subject: Don't try to "define" intelligence
Message-ID: <1992Sep6.195000.3465@Princeton.EDU>
Summary: Re: Don't try to define flight
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In article <715493498@sheol.UUCP> throopw@sheol.UUCP (Wayne Throop) writes:
>since no artificial so-called "flying machine" has really flapped
>its wings as the primary method of propulsion, they are all
>distinguishable from natural flyers, the criterion has never been
>acheived, so it's too soon to weaken it.  So clearly, humans have not
>yet attained artificial flight. 

Unfortunately, this misses the point of my suggestion not to try to
define intelligence but to concentrate instead on generating
Turing-indistinguishable performance capacity. Of course if

(1) there were nothing special about mental states, or
(2) performance capacity were identical with mental states, or
(3) performance capacity picked out an interesting natural category
    of its own (say, staying "cognitively aloft," which would be
    analogous to the common property of both biological and artificial
    flight)

then Wayne's implied objection would be well taken. But none of the
above is the case. We all know there is something special about having
mental states, and no definitional constraint on performance will get
around that (even less will it get AT it). Flight, on the other hand,
is pure performance. So with flight, you can shoot for flight,
simpliciter, i.e., anything that gives a system the performance
capacity to get and stay aloft on its own (excluding the obvious forms
of cheating, like rocketing, orbiting, etc.). Or you can shoot for
biological flight, in which case you WOULD have to capture all the
relevant performance capacities of organisms (including flapping).

But intelligence, which no definition will succeed in conferring,
except by arbitrary fiat, on anything beyond its sole current possessor
(namely, creatures with mental states), can only be understood by
understanding what it takes to generate ALL of its current possessors'
performance capacities -- and of course even that is no guarantee. But
to settle for less a priori is to stipulate, completely arbitrarily, that
intelligence is really just this part or that part of our total
performance capacity. Which is in turn like saying, a priori, that
flight is really just falling, hopping, or taxiing on the ground.

The October SIGART Bulletin will contain an Editorial by Lewis
Johnson plus commentaries by Stuart Shapiro and myself, on a topic
related to this. I will post this in a subsequent message.

                   Stevan Harnad
Department of Psychology      Cognition et Mouvement URA CNRS 1166
  Princeton University            Universite d'Aix Marseille II
   Princeton NJ 08544           13388 Marseille cedex 13, France

-- 
Stevan Harnad  Department of Psychology  Princeton University
harnad@clarity.princeton.edu / harnad@pucc.bitnet / srh@flash.bellcore.com 
harnad@learning.siemens.com / harnad@elbereth.rutgers.edu / (609)-921-7771


