Path: utzoo!attcan!uunet!snorkelwacker!apple!rutgers!rochester!cornell!oravax!daryl
From: daryl@oravax.UUCP (Steven Daryl McCullough)
Newsgroups: comp.ai
Subject: Re: Some thoughts on the Searle controversy
Summary: Interpretation is needed for communication, and is not unique.
Message-ID: <1598@oravax.UUCP>
Date: 17 Jul 90 17:30:20 GMT
References: <4977@milton.u.washington.edu> <603@ntpdvp1.UUCP> <1597@oravax.UUCP> <5146@milton.u.washington.edu>
Organization: Odyssey Research Associates, Ithaca NY
Lines: 83

In article <5146@milton.u.washington.edu>, forbis@milton.u.washington.edu (Gary Forbis)
writes:
> In article <1597@oravax.UUCP> daryl@oravax.UUCP (Steven Daryl McCullough) writes:
> >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.

I'm not sure what you mean by this. For many (most? all?) purposes,
the operational semantics is all you need to know.

> >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 prepared for this response.  If when you refer to a program you
> refer to the syntax then what you say is true.

No, to me the important fact about a program is not its syntax, but
its operational semantics; how a machine running the program would
behave.

> 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 because we mean more by "program" than we mean
> by "syntax."

I don't think we're in any serious disagreement here. To say that a
program "has a bug" or "is intelligent", it is necessary to give an
interpretation, in addition to the operational semantics. Our only
disagreement is that you think that the programmer has the final say
on what the "real" semantics is, while I don't agree; to me, any
consistent interpretation is as correct as any other.

> 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.

Agreed. The problem is there with human communication, as well.

> 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.

Who made the programmer God? If I pay for a program, I can interpret
it any way I want to. It seems to me that any interpretation that can
be consistently maintained is "correct", and this includes both
statements in English and programs. The example of the medical expert
system program is to the point here: the expert system is
*simultaneously* computing some recursive function of integers, and is
diagnosing disease. Perhaps the programmer intended it to only
diagnose disease, but so what?

> >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 artificial intelligence the system must handle unpredictable
> inputs? English is a living language; interpretations change over time.

The inputs to a computer are not English, they are electrical signals.
An enormous amount of interpretation is needed to get English out of
it---the highs and lows of the electrical signal must be interpreted
as bits, and groups of eight bits interpreted as numbers from 1 to
255, which are interpreted as characters.

Daryl McCullough