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Article 5105 of comp.ai.philosophy:
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>From: bill@NSMA.AriZonA.EdU (Bill Skaggs)
Newsgroups: comp.ai.philosophy
Subject: Re: Categories: bounded or graded?
Message-ID: <1992Apr15.010721.17700@organpipe.uug.arizona.edu>
Date: 15 Apr 92 01:07:21 GMT
References: <1992Apr14.143822.10246@psych.toronto.edu>
Sender: news@organpipe.uug.arizona.edu
Reply-To: bill@NSMA.AriZonA.EdU (Bill Skaggs)
Organization: Center for Neural Systems, Memory, and Aging
Lines: 45

In article <1992Apr14.143822.10246@psych.toronto.edu> 
christo@psych.toronto.edu (Christopher Green) writes:
>
>From: Stevan Harnad
>
>We disagree even more on categories. I think the Roschian view you
>describe is all wrong, and that the "classical" view -- that categories
>have invariant features that allow us to categorize in the all-or-none
>way we clearly do -- is completely correct. Introspections about how
>we categorize are irrelevant (did we expect introspection to do
>our theoretical work for us, as cognitive theorists?), as are
>reaction times and typicality judgments. The performance capacity
>at issue is our capacity to learn to sort and label things as we do, not
>how fast we do it, not how typical we find the members we can
>correctly sort and label, not the cases we CANNOT sort and label,
>not the metaphysical status of the "correctness" (just its relation
>to the Skinnerian consequences of MIScategorization), and certainly
>not how we happen to think we do it. And the categories of interest
>are all-or-none categories like "bird," not graded ones like "big."

  With Wittgenstein in mind, I ask:  what are the invariant features
that characterize a "game"?

  Wittgenstein, of course, argued that there are none.  His view,
and an increasing popular view among linguists (see, for example,
Lakoff's "Women, Fire, and Dangerous Things") is that natural
categories are not defined by invariant features, but rather
by radiation from prototypes.  (Thus a bird is anything that is
sufficiently similar to the prototypical bird, which is something
like a sparrow.)  I don't want to sound like Mikhail Zeleny, but
I will go so far as to say that the idea that categories are
defined by invariant features is no longer really defensible.

  In my opinion the belief that natural categories are defined
by invariant features leads to all kinds of nasty problems.  When
we are talking about mind, it leads us to try to discover the
invariant features necessary for something to have a mind.  This
inevitably plunges us into squabbles and contradictions, because
there just aren't any.  There is only the prototypical mind, which
is the human mind.  Anything sufficiently similar to the human
mind is a mind; but, as Chris Green pointed out, "sufficiently"
is a vague word, and in fact the line gets drawn whereever it is
most convenient for us to draw it.

	-- Bill


