Path: utzoo!attcan!uunet!jarthur!usc!venera.isi.edu!smoliar
From: smoliar@vaxa.isi.edu (Stephen Smoliar)
Newsgroups: comp.ai
Subject: Re: Hayes vs. Searle
Keywords: Symbols
Message-ID: <14417@venera.isi.edu>
Date: 25 Jul 90 13:50:30 GMT
References: <129.26a5feab@csc.fi> <14385@venera.isi.edu> <58376@bbn.BBN.COM>
Sender: news@venera.isi.edu
Reply-To: smoliar@vaxa.isi.edu (Stephen Smoliar)
Organization: USC-Information Sciences Institute
Lines: 49

In article <58376@bbn.BBN.COM> bkort@BBN.COM (Barry Kort) writes:
>In article <14385@venera.isi.edu> smoliar@vaxa.isi.edu (Stephen Smoliar)
>writes:
>
> > This argument assumes that the human brain HAS symbols (or, at least,
> > that is implied through the use of the possessive "its").  There is
> > no evidence that this is the case.  I think it would be fair to say
> > that the point is still up for debate, just like the premise that the
> > human brain "has" mental images.
>
>I don't understand this, Steve.  Spoken and written language symbolize
>the elements of our world.  And these word-symbols are stored and processed
>in the brain.  (At least that's where *I* store them!)  So while the
>point may be worthy of debate, how can you argue that there is no evidence?
>
I guess we are in a position of mutual conflict, here, Barry.  How can you
argue that there IS evidence?  Your introspection is your personal abstraction
of what you think is going on.  There is nothing wrong with that, as long as
you don't fall into the trap of confusing the abstraction with the reality.

Look, let's try to establish a level playing field.  In his "Symbol Grounding
Problem" paper, Stevan Harnad defines a symbol system to be "(1) a set of
arbitrary 'PHYSICAL TOKENS' (scratches on paper, holes on a tape, events
in a digital computer, etc.) that are (2) manipulated on the basis of 'EXPLICIT
RULES' that are (3) likewise physical tokens and STRINGS of tokens.  The rule-
governed symbol-token manipulation is based (4) purely on the SHAPE of the
symbol tokens (not their 'meaning'), i.e., it is purely SYNTACTIC, and consists
of (5) 'RULEFULLY COMBINING' and recombining symbol tokens.  There are
(6) primitive ATOMIC symbol tokens and (7) COMPOSITE symbol-token strings.
The entire system and all its parts -- then atomic tokens, the composite tokens,
then syntactic manipulation (both actual and possible) and the rules -- are all
(8) 'SEMANTICALLY INTERPRETABLE:'  The syntax can be SYSTEMATICALLY assigned a
meaning (e.g., as standing for objects, as describing states of affairs)."
Given the constraints of such a definition, I think that the level of debate
may descend to the point of arguing whether or not the sorts of events which
take place at the neuronal level constitute the sorts of physical tokens which
form the core of Harnad's definition.  In other words we can, indeed, argue
over whether or not there is any evidence!

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"It's only words . . . unless they're true."--David Mamet