From: zeleny@zariski.harvard.edu (Mikhail Zeleny)
Newsgroups: comp.ai.philosophy,sci.lang
Subject: Re: Categories: bounded or graded?
Date: 15 Apr 92 12:10:21 GMT
Organization: Dept. of Math, Harvard Univ.

In article <1992Apr15.010721.17700@organpipe.uug.arizona.edu>
bill@NSMA.AriZonA.EdU (Bill Skaggs) writes: 

>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."

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

To cite Johan Huizinga, play is "a voluntary activity or occupation
executed within certain limits of time and place, according to rules freely
accepted but absolutely binding, having an aim in itself and accompanied by
a feeling of tension, joy and the consciousness that it is ``different''
from ``ordinary life''." ("Homo Ludens", Boston: Beacon Press, 1955, p.28)

BS:
>  Wittgenstein, of course, argued that there are none.  

Tant pis pour lui.

BS:
>							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.

On the other hand, see anything by Noam Chomsky or Jerrold Katz for a
diametrically opposite view.

BS:
>			       (Thus a bird is anything that is
>sufficiently similar to the prototypical bird, which is something
>like a sparrow.) 

"Any feathered vertebrate animal; a member of the second class (_Aves_) of
the great Vertebrate group, the species of which are most nearly allied to
the Reptiles, but distinguished by their warm blood, feathers, and
adaptation of forelimbs as wings, with which most species fly in the air."
(OED) 

BS:
>		  I don't want to sound like Mikhail Zeleny,

You won't.

BS:
>							     but
>I will go so far as to say that the idea that categories are
>defined by invariant features is no longer really defensible.

Nonsense.

BS:
>  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.

Sounds like a convenient excuse to avoid hard work.

>	-- Bill

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