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Article 4564 of comp.ai.philosophy:
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>From: jeff@aiai.ed.ac.uk (Jeff Dalton)
Newsgroups: comp.ai.philosophy
Subject: Re: The Systems Reply I
Keywords: syntax vs. semantics
Message-ID: <6430@skye.ed.ac.uk>
Date: 18 Mar 92 17:43:15 GMT
References: <44765@dime.cs.umass.edu> <6422@skye.ed.ac.uk> <45020@dime.cs.umass.edu>
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In article <45020@dime.cs.umass.edu> orourke@sophia.smith.edu (Joseph O'Rourke) writes:
>I probably shouldn't have said the machine "knows" anything, even in
>scare quotes.  The point is that the machine manipulates some bits/strings/
>symbols in a manner differently from other symbols.  It partitions the
>universe of symbols into primitive classes: these strings are appropriate
>to be passed to this function, and these strings are not.  And it uses
>the symbols in a manner consistent with their meaning (to us).  Surely
>the machine doesn't "know" that these bits represent a "real number,"
>in the sense that we know real numbers.  But it *is* making distinctions
>among its symbols, and using them appropriately.

Saying "it partitions", "it is making distinctions", etc, looks to me
like begging the question.

Anyway, modulo speed, we could replace a computer by one with, say,
three instructions (add 1, subtract 1, transfer if 0).  There's
certainly a sense in which this machine treats everything as a number
(or numeral), but the only distinction it's making is whether the
number is zero or not.

Now you might say that the machine + the program is in effect a
different machine that is makeing more interesting distinctions.
But unless you think any manipulations whatsoever count as assigning
meaning, I don't see how you can tell the machine is assigning 
meaning without knowing a great deal more about what it's program is.

In any case, evenif we allow the use of "meaning" for the things
you're talking about, is it the relevant sense of meaning, or is
some kind of equivocation taking place?

>	You said: "I still haven't seen a satisfactory answer to the point 
>that the Room manipulates meaningless symbols ([...]) without any way to 
>attach meaning to them." What I am claiming is that the symbols cannot 
>be *completely* meaningless; for if they were, they would be manipulated 
>without distinction.  Since the machine is discriminating amongst its 
>symbols, they must have some meaning to it, the machine. 

I find it impossible to escape the feeling that you are talking
(at best) about a different sense of meaning.

In any case, I don't see why this meaning will have ot line up
witht the right meaning, eg, why "cats" will line up with cats
and not with cherries.

>	If you feel such discrimination is not a type of primitive
>meaning, perhaps you should sketch the key requirements of what constitutes
>a meaningful symbol in your theory of meaning.

I don't have a theory of meaning and, as always, I reject the
suggestion that the burden of proof should be on the "anti-AI"
side to provide definitions.

On the other hand, if you can show that there is a widely accepted
theory of meaning according to which such discrimination counts as
meaning, I'd be interested in knowing more about it.

> >[...]Now, the Geometry Room, for example, can
> >answer questions about geometry (even if the person in the Room hasn't
> >a clue).  But is that because this system understands geometry or
> >because the programmers (or the mathematicians they consulted)
> >understand geometry?
>
>A good portion of what we learn is taught to us.  Do I understand
>geometry because my teachers did?  Well, yes, in part.  But I have
>demonstrated mastery by conjecturing and proving theorems myself, 
>going beyond direct teaching.  We should apply similar criteria to a 
>machine.

Consider two cases.  1. You understand geometry.  2. You don't,
but someone has given you a set if rules for answering geometry
questions.  Now in 2 some one of the people involve understands
geometry, but it's not you.

There's a difference between being taught geometry and being taught
some way to fake it.  If you want to say they're the same, you should
at least produce an argument.

-- jd


