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From: dgordon@teknowledge-vaxc.ARPA (Dan Gordon)
Newsgroups: comp.cog-eng,comp.ai
Subject: Re: The symbol grounding problem: Against Rosch & Wittgenstein
Message-ID: <14269@teknowledge-vaxc.ARPA>
Date: Wed, 1-Jul-87 18:33:50 EDT
Article-I.D.: teknowle.14269
Posted: Wed Jul  1 18:33:50 1987
Date-Received: Fri, 3-Jul-87 01:52:51 EDT
References: <.... <6174@diamond.BBN.COM> <917@mind.UUCP> <14184@teknowledge-vaxc.ARPA> <949@mind.UUCP>
Reply-To: dgordon@teknowledge-vaxc.UUCP (Dan Gordon)
Organization: Teknowledge, Inc., Palo Alto CA
Lines: 33
Xref: mnetor comp.cog-eng:171 comp.ai:601

In article <949@mind.UUCP> harnad@mind.UUCP (Stevan Harnad) writes:
>
>
>dgordon@teknowledge-vaxc.ARPA (Dan Gordon)
>of Teknowledge, Inc., Palo Alto CA writes:
>
>>	There is no reliable, consensual all-or-none categorization performance
>>	without a set of underlying features?  That sounds like a restatement of
>>	the categorization theorist's credo rather than a thing that is so.
>
>If not, what is the objective basis for the performance? And how would
>you get a device to do it given the same inputs?

Not a riposte, but some observations:

1) finding an objective basis for a performance and getting a device to
do it given the same inputs are two different things.  We may be able
to find an objective basis for a performance but be unable (for merely
contingent reasons, like engineering problems, etc., or for more funda-
mental reasons) to get a device to exhibit the same performance.  And,
I suppose, the converse is true: we may be able to get a device to mimic
a performance without understanding the objective basis for the model
(chess programs seem to me to fall into this class).

2) There may in fact be categorization performances that a) do not use
a set of underlying features; b) have an objective basis which is not
feature-driven; and c) can only be simulated (in the strong sense) by
a device which likewise does not use features.  This is one of the 
central prongs of Wittgenstein's attack on the positivist approach to
language, and although I am not completely convinced by his criticisms,
I haven't run across any very convincing rejoinder.

Maybe more later, Dan Gordon