Path: utzoo!attcan!uunet!aplcen!haven!uvaarpa!mcnc!rti!ntpdvp1!kenp
From: kenp@ntpdvp1.UUCP (Ken Presting)
Newsgroups: comp.ai
Subject: Some thoughts on the Searle controversy
Summary: Where to find a definition of "truth", and what to do with it.
Message-ID: <601@ntpdvp1.UUCP>
Date: 11 Jul 90 19:38:58 GMT
Organization: SNA Solutions Inc., Contract Programming Group
Lines: 99

kohout@wam.umd.edu (Robert C. Kohout) writes:

>  . . . For example, I once pointed out what I
> consider to be a serious flaw in Searle's CR logic. One of Searle's
> defenders, using the restatement of Searle's position published in 
> "Scientific American", replied that Searle only uses the Chinese Room
> to establish the fact that (pardon me if I don't get this exactly)
> "syntax is neither a necessary or sufficient condition for semantics."
> 
> I happen to agree with this statement. Because of this, I was told that I
> needn't worry about the Chinese Room at all - I'm beyond that point. To
> restate it in my own, quasi-logical terms, I was told that the truth of the
> conclusion justified the fallacy of the argument. Needless to say, this
> bothered me enormously, but it obviously never occurred to the pro-Searlite
> that there was anything wrong with such reasoning.  I believe that this type

Bob, the fallacy here is to suppose that "you needn't worry about Searle's
arguement" implies "Searle's argument is valid".    

Because you have misread Searle's argument, you do not understand it.  If 
for some reason it is important to you to understand Searle, then you should
take the time to re-read his latest paper. If you do not wish to take the
time, don't worry - even after you come to understand the argument, it will
not change your opinion, since you already agree with the conclusion.   


> of exchange is typical of the entire debate. On the one side, there are the
> rationalists - Computer types, fluent in mathematics and confident of the
> powers of reason.  . . . 
> 
> . . .  "If they would only give us a definition for
> intelligence, I could prove that it is possible to create an intelligent
> machine." Never mind that no one has ever adequately defined intelligence -
> this position is a truism. If it were possible to represent intelligence
> by a purely formal definition, then of course we could program a purely
> formal system to be 'intelligent' (this of course assumes that the problem
> with defining intelligence is the same problem implicit in defining any
> abstract concept - 'truth', 'beauty', 'meaning', etc., and that if we
> could truly define one we could define them all in a similar fashion.).
> . . . 

Bob, you can't possibly mean this as you have stated it.  I assume you
are familiar with unsolvable problems in computability theory.  Surely
the Halting problem is "represented by a purely formal definition", yet 
it is impossible to "program a purely formal system" to solve it.

> 
> A recent poster referred to a proof of the fact that semantics cannot always
> be represented syntactically. I do not have the details here, and I hope
> that I have stated his position correctly. I do not question the proof or
> his interpretation of it, though I am not sure I follow either, but I
> would like to make the following point. The poster referred to the fact that
> semantic values, such as 'truth' cannot be represented syntactically.
> Somehow, these things are known, but there exists no formalism for their
> representation. . . . 

You have very seriously misstated my position.  You are apparently 
unfamiliar with the work of Alfred Tarski on the definition of truth.
For a very accessible discussion, you may want to read "The Semantic
Conception of Truth," _Philosophy and Phenomenological Research_, 1944.
A more formal treatment is "The Concept of Truth in Formalized Languages,"
in _Logic, Semantics, Metamathematics_ (New York: Oxford, 1956).

Roughly, here are the main points:

1) Any language which includes a predicate for "truth" and allows referring
expressions to denote sentences of the language is "semantically closed",
and every formal system stated in that language will be inconsistent,
because of the Liar paradox.

2) Truth, as it applies to the sentences of a particular language, can be
precisely defined, but only in a *second* language, called a "metalanguage".


> So is Searle right? Forgetting, and forgiving his Chinese Room fiasco, which
> as I have said is based upon inexcusably bad logic, he is hard to argue
> with, to a point. His views in regards the relationship between syntax and
> semantics seem correct to me, but I do not see that this implies that we
> will never create an intelligent machine. That, however, is simply my own
> opinion, and I can offer no well reasoned argument for it.
> 
> 
> Bob Kohout

Searle is *not* arguing that we will never create an intelligent machine.
He is arguing (I will try to put this into your terms) that no program can
be a sufficient condition for intelligence.  

If you believe:

1. Programs are just syntax (or just mechanical)
2. Syntax is not a sufficient condition for semantics
3. Semantics is a necessary condition for intelligence

then you have no choice but to accept Searle's conclusion.   For my own 
part, I deny (1).  I think that programs have semantics as well as syntax.


Ken Presting  ("Fluent in, oh, well, just forget it")