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From: tjhorton@utai.UUCP
Newsgroups: comp.cog-eng
Subject: Concepts and Definitions (was Re: The symbol grounding problem)
Message-ID: <3971@utai.UUCP>
Date: Wed, 24-Jun-87 02:45:08 EDT
Article-I.D.: utai.3971
Posted: Wed Jun 24 02:45:08 1987
Date-Received: Thu, 25-Jun-87 05:41:35 EDT
References: <764@mind.UUCP> <768@mind.UUCP> <770@mind.UUCP>
Reply-To: tjhorton@ai.UUCP (Timothy J. Horton)
Organization: CSRI, University of Toronto
Lines: 49
Summary: What's definition got to do with it?  Who needs a definition when a ...

--------------- recap on -----------------------------------------------
In article <6721@diamond.BBN.COM> aweinste@Diamond.BBN.COM (Anders Weinstein)
writes [in reply to someone]:
> >                         Conceptual combination allows us to go
> >from 'tomato' and 'juice' to 'tomato juice'. I assume there is no
> >argument that this new category may be acquired, sight unseen, 
> >by symbolic processing. Presumably there must be atomic=primitive
> >concepts, however, and where do these come from? It must be
> >by a process different from that usable to acquire the concept
> >'tomato juice'.
>
>Of course *some* concepts can be acquired by definition. However, the
>"classical empiricist" doctrine is committed to the further idea that there
>is some priveleged set of *purely sensory* concepts and that all non-sensory
>concepts can be defined in terms of this basis. [...] If you regard "juice"
>as a "primitive" concept, then you do not share the classical doctrine.
>(And if you do not, I invite you try giving necessary and sufficient
>conditions for juicehood.)
--------------- recap off ----------------------------------------------

The first gentleperson did not say anything about definition (or did s/he?)
When/why/how would I ever need a "definition" in order to learn something?

Does a male mosquito need a "definition" of "female mosquito?"
Yet its "concept" of "female mosquito" most surely isn't a definition that
I would accept - just how to recognize one plus what gets done about it,
in *his* terms.  Now, the mosquito's concept of a particular female
presumably depends on some innate mechanisms (so does mine! so does mine!)
but the point is, he needs no DEFINITION for "this particular female mosquito".

Do I need a "definition" of magnetism to have the concept?
There isn't even a half baked *theory* for it, and certainly not a definition.
What does magnetism mean to me?  Not much more than a "force" which selective-
ly pulls certain kinds of metals together.  And I happen to know that super-
conducting material repels magnets - drop a magnet over a superconductor and
it will stay suspended in mid-air  (I know it's true.  I saw it on TV.  :-)
Does this constitute a definition that would satisy the perspective of an
omniscent god?  Have I not learned a concept for magnetism?  

Do concepts require necessary and sufficient conditions?
If they do, then I better give back my engineering degree :-)

Timothy J Horton, Dept Comp Sci, UofToronto, <tjhorton@utai>

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"The reasonable man adapts himself to the world, the unreasonable man
adapts the world to himself, therefore, all progress depends on the
unreasonable man." -- George Bernard Shaw
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