Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!rutgers!mcnc!rti!ntpdvp1!kenp
From: kenp@ntpdvp1.UUCP (Ken Presting)
Newsgroups: comp.ai
Subject: Re: Some thoughts on the Searle controversy
Summary: Semantics of the Program is more than operational
Message-ID: <611@ntpdvp1.UUCP>
Date: 24 Jul 90 22:40:06 GMT
Organization: SNA Solutions Inc., Contract Programming Group
Lines: 69

>
> (Gary Forbis) writes:
> >In article <603@ntpdvp1.UUCP>, kenp@ntpdvp1.UUCP (Ken Presting) writes:
> >
> >> So the program is not just "pure syntax" - at least some of the
> >> expressions in the program have the same meaning as ordinary English
> >> expressions.
>
> I agree with ken here so I will respond.

Gary has attempted to defend a view which is much stronger than I would
advocate myself.

> > (Daryl McCullough) wrote:
> >For example, take an expert system for medical diagnosis. When the
> >expert system prints out a message like "The patient shows indications
> >of suffering from Lyme disease" (or whatever), this string of
> >characters can be given its usual English interpretation. . . .

I want to consider (for the moment) NOT the behavior of the computer which
prints the sentences, but rather the meaning of the program which does the
printing.  Take the instruction:

      printf("The patient shows ... Lyme disease\n");

I am NOT saying that the quoted string refers to a patient or a disease.
I think Daryl is right about the variability of the interpretation of the
printed symbols.

What I AM saying is that the *source code* refers to printed letters and
newlines, in exactly the same way that quoted poetry does:

      "Let us go then, you and I/ When the evening is spread out
      against the sky/ Like a patient etherised upon a table/ ..."
      (From "The Love Song of J. Alfred Prufrock", by T. S. Eliot)

The crucial observation here is that both English and C include *quoted
strings* as syntactical elements.  Sometimes the quoted strings include
typographic information (newlines) as well as just a sequence of letters.

> (Daryl:)
> >Because the interpretation of a program is not unique, I believe that,
> >for anyone to demonstrate that they have an artificially intelligent
> >machine, it is not enough to give the machine, or the program---one
> >must also give the proper *interpretation* of the inputs and outputs.
> >A program may be intelligent according to some interpretations, and
> >not according to others.
>
> (Gary:)
> The proper way to interpret output formatted in English is in English.
> What does it mean to "give the proper *interpretation* of the inputs" when
> to be deemed an artificail intelligence the system must handle unpredictable
> inputs?  English is a living language; interpretations change over time.

I diagree with both of these positions.  I think that the semantics of the
programming language include enough information to completely determine
the intelligence of the machines that implement any given program.  I should
probably add that the issue is by no means straightforward - run-time
libraries, internal data representations, peripheral hardware addresses, ad
nauseum, make the semantics of programming languages as complex as natural
languages.  Sure, the syntax is easy.  But semantics is a lot harder.

The interpretation of the program's *data* is a very different issue from
the interpretation of the *source code*.  How to interpret formatted data
is the "symbol grounding problem", and solving it is probably equivalent
to defining "intelligence".


Ken Presting   ("'God' is an unresolved external reference")