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From: marty1@houdi.UUCP (M.BRILLIANT)
Newsgroups: comp.ai,comp.cog-eng
Subject: Re: The symbol grounding problem
Message-ID: <1200@houdi.UUCP>
Date: Tue, 30-Jun-87 16:49:32 EDT
Article-I.D.: houdi.1200
Posted: Tue Jun 30 16:49:32 1987
Date-Received: Thu, 2-Jul-87 00:48:37 EDT
References: <764@mind.UUCP> <768@mind.UUCP> <770@mind.UUCP> <6174@diamond.BBN.COM> <937@mind.UUCP>
Organization: AT&T Bell Laboratories, Holmdel
Lines: 78
Summary: placeholder
Xref: mnetor comp.ai:594 comp.cog-eng:165

In article <937@mind.UUCP>, harnad@mind.UUCP (Stevan Harnad) writes:
> ...
> marty1@houdi.UUCP (M.BRILLIANT) of AT&T Bell Laboratories, Holmdel asks:
> >	how about walking through what a machine might do in perceiving a chair?
> >	... (a few steps skipped here)
> >	Now the machine has a form.  If the form is still unfamiliar,
> >	let it ask, "What's that, Daddy?"  Daddy says, "That's a chair."
> >	The machine files that information away.  Next time it sees a
> >	similar form it says "Chair, Daddy, chair!" ...
> 
> Now you've lost me completely. Having acknowledged the intricacies of
> sensory transduction, you seem to think that the problem of categorization
> is just a matter of filing information away and finding "similar forms."

I think it is.  We've found a set of lines, described in 3 dimensions,
that can be rotated to match the outline we derived from the view of a
real chair.  We file it in association with the name "chair."  A
"similar form" is some other outline that can be matched (to within
some fraction of its size) by rotating the same 3D description.

> I think the main details are missing, such as how the successful
> categorization is accomplished......

Are we having a problem with the word "categorization"?  Is it the
process of picking discrete objects out of a pattern of light and
shade ("that's a thing"), or the process of naming the object ("that
thing is a chair")?

> ..... Your account also sounds as if it
> expects innate feature detectors to pick out objects for free, more or
> less nonproblematically.....

You left out the part where I referred to computer-aided-design
modules.  I think we can find outlines by looking for contiguous
contrasts.  If the outlines are straight we (the machine, maybe also
humans) can define the ends of the straight lines in the visual plane,
and hypothesize corresponding lines in space.  If hard-coding this
capability gives an "innate feature detector" then that's what I want.

> ...... and then serve as a front end for another
> device (possibly a conventional symbol-cruncher a la standard AI?)
> that will then do the cognitive heavy work. I think that the cognitive
> heavy work begins with picking out objects, i.e., with categorization.

I think I find objects with no conscious knowledge of how I do it (is
that what you call "categorization")?  Saying what kind of object it is
more often involves conscious symbol-processing (sometimes one forgets
the word and calls a perfectly familiar object "that thing").

> I think this is done nonsymbolically, on the sensory traces, and that it
> involves learning and pattern recognition -- both sophisticated
> cognitive activities.

If you're talking about finding objects in a field of light and shade, I
agree that it is done nonsymbolically, and everything else you just said.

> .....  I also do not think this work ends, to be taken
> over by another kind of work: symbolic processing.....

That's where I have trouble.  Calling a penguin a bird seems to me
purely symbolic, just as calling a tomato a vegetable in one context,
and a fruit in another, is a symbolic process.

> ..... I think that ALL of
> cognition can be seen as categorization. It begins nonsymbolically,
> with sensory features used to sort objects according to their names on
> the basis of category learning; then further sorting proceeds by symbolic
> descriptions, based on combinations of those atomic names. This hybrid
> nonsymbolic/symbolic categorizer is what we are; not a pair of modules,
> one that picks out objects and the other that thinks and talks about them.

Now I don't understand what you said.  If it begins nonsymbolically,
and proceeds symbolically, why can't it be done by linking a
nonsymbolic module to a symbolic module?

M. B. Brilliant					Marty
AT&T-BL HO 3D-520	(201)-949-1858
Holmdel, NJ 07733	ihnp4!houdi!marty1