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From: forbis@milton.u.washington.edu (Gary Forbis)
Newsgroups: comp.ai
Subject: Re: Some thoughts on the Searle controversy
Message-ID: <5146@milton.u.washington.edu>
Date: 17 Jul 90 01:03:45 GMT
References: <4977@milton.u.washington.edu> <603@ntpdvp1.UUCP> <1597@oravax.UUCP>
Organization: University of Washington, Seattle
Lines: 73

In article <1597@oravax.UUCP> daryl@oravax.UUCP (Steven Daryl McCullough) 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.

>Ken, when you first mentioned your objection to the premise that
>programs are "pure syntax, without semantics", I assumed that you had
>in mind the operational semantics of the programming language; that
>is, the way the machine executes programs written in the language.
>Every programming language that can be compiled or interpreted must
>have an operational semantics, and so every program automatically has
>a semantic, as well as a syntactic, component.

This is true but insufficient to describe what one means when one talks
about a program.

>However, you seem to be saying something stronger here; that programs
>can be given some kind of linguistic meaning, in the way that English
>sentences can. Although this is undoubtedly true, this meaning is not,
>in my opinion, inherent in the program, but is imposed on the program
>by the user.

I was prepaired for this response.  If when you refer to a program you
refer to the syntax then what you say is true.  When I refer to a program
I refer to the intended semantics the syntax will generate.  A program
can have a bug in it even though syntaxtically correct becuase we mean
more by "program" than we mean by "syntax."  If you tell me what way
English sentences are given meaning then I might be able to tell you
if programs are given meaning in the same way.

>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. However,
>this interpretation is not the only interpretation possible; for
>instance, the inputs and outputs can be interpreted as integers, and
>then the program can then be interpreted as computing some
>tremendously complicated recursive function. It is quite possible for
>two or more interpretations of a program's output to be correct
>simultaneously.

I was about to reuse this text, substituting "expert" for program, and dropping
the word "system" but have chosen not to do so.  I still have to generate an
equivilent number of new lines so postnews will let me send this.

There is nothing saying any human utterance needs to be interpreted in any
particular fashion.  Any argument about how computer output can be interpreted
also be applied to humans.  Any attempt to separate interpretations from 
intended interpretations is doomed.  I could interpret the English sentence
"The sky is blue." as "The cat is dead." but the interpretation would be wrong.
While it is true that "it is quite possible for [there to be] two or more 
interpretations of a program's output"[my insertion] only one will be correct
and that one is the one intended by the programmer.

>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.

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.

>Daryl McCullough

--gary forbis@milton.u.washington.edu