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From: ragerj@nucsrl.UUCP
Newsgroups: comp.ai
Subject: Re: Learing about AI (was Re: A List of AI Books (for beginners))
Message-ID: <3800004@nucsrl.UUCP>
Date: Sat, 21-Feb-87 17:07:01 EST
Article-I.D.: nucsrl.3800004
Posted: Sat Feb 21 17:07:01 1987
Date-Received: Mon, 23-Feb-87 01:52:09 EST
References: <12992@sun.uucp>
Organization: Northwestern U, Evanston IL, USA
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from: / sher@rochester.ARPA (David Sher) /  8:17 am  Feb 13, 1987 /
>I think there seems to be something of a misconception regarding the
>place of logic wrt AI and computer science in general.  To start with
>I will declare this:
> Logic is a language for expressing mathematical constructs. 
>It is not a science and as far as artificial intelligence is concerned
>the mathematics of logic are not very relevant.  Its main feature
>is that it can be used for precise expression.  

Logic is a branch of mathematics. The last time I checked mathematics
was a science. Its relevancy to AI is a matter of opinion.


> So why use logic rather than a more familiar language, like english.
> ...
> However the problem is that few of us knowledge
> engineers have the talent to be precise in our everyday language.

>Thus for decades engineers, scientists, and statisticians have used
>logic to express their ideas since even an incompetent speaker can be
>clear and precise using logical formalisms.  However like any language
>with expressive power one can be totally incomprehensible using logic.

First, you aren't talking about Logic, you are talking 
about mathematical notation. Second, the reason that mathematicians use
this notation has nothing to do with their inability to express concepts in 
English. It has to do with the inexpressibliity of the concepts in 'ordinary
English'. Mathematical notation is the specialized language of the 
mathematical disciplines. All disciplines have a specialized language, a set
of terms with precise meanings in that field. A good philosopher, writing
a good paper, writes in what seems to be ordinary English. It is not. It is
English augmented by the argot of the field. This is true even though the
difference may not be obvious to an outsider, since it looks like English.
The language of mathematics doesn't look like English. 


So where does this leave English? It is a wonderful language and I love it.
It is not a specialized tool for working in a particular discipline. It 
is a means of everyday communication, an amazing miracle of generality.
It does not have the expressive power of logic. Do not try to use it for what 
it is not suited for. (Before anyone says anything, when the first English
grammars were devised they were modeled on these of Latin, in which
language one does not end sentences with prepositions. It has always been 
common practice to use propositions as sentence-ending particles in English.)


>Note: I am not a logician but I use a lot of logic in my everyday
>work which is probabilistic analysis of computer vision problems
>-David Sher

When you say you use a lot of logic, do you really mean it? Recursive 
function theory? Saturated model theory? Or do you mean you use the 
vernacular of the mathematician?

John Rager

sher@rochester
{allegra,seismo}!rochester!sher
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