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From: csma@lifia.imag.fr (Ch. de Sainte Marie)
Newsgroups: comp.ai.philosophy
Subject: Re: Reasoning Paradigms
Message-ID: <6875@lifia.imag.fr>
Date: 8 Oct 90 21:06:59 GMT
References: <9963@ccncsu.ColoState.EDU> <3586@media-lab.MEDIA.MIT.EDU> <69347@lll-winken.LLNL.GOV>
Reply-To: csma@lifia.UUCP (Ch. de Sainte Marie)
Organization: LIFIA-INPG
Lines: 46

In article <69347@lll-winken.LLNL.GOV> loren@tristan.llnl.gov (Loren Petrich) writes:
> [...]
>a major form of reasoning. But I wonder how much of our reasoning
>works by what might best be called "fuzzy logic" -- a logic in which
>predicates can not only have the values "true" or "false", but any
>value in between. That may well describe how we reason about uncertain
>things. Traditional logic presupposes a discreteness that is often
>lacking in the world around us. Any comments?

It seems to me that reasonning is, to a great extent, about making
choices; fuzzy logic is all about avoiding choices as long as possible.
So, fuzzy logic does not seem like the best tool for rational thinking.

I agree (just because it would'nt change the condition if I did'nt :-)
that factual knowledge about the world around us most often lacks
discreteness, but I propose (and I suppose as a working hypothesis)
that a prerequisite to reasonning is forcing discreteness on reluctant data.

In hypothetico-deductive reasonning, you don't use fuzzy logic (I, for
one, don't: I could'nt possibly, I don't even know what it is):
you examine what would be the outcome, should this or that be true (or
false).

It seems to me that when one reasons in face of
uncertainty, one proceeds in a similar way: choose some facts to be
true, others to be false, and throw out the rest as irrelevant; then,
use the newly `certain' facts to reason. The criterion by which one selects
which facts to use, and which to reject, can be (in facts, is most
probably) probabilist to an extent, but the logic does not seem to be the
least fuzzy.  One can eventually have to change what one chose to believe,
but it can only be when faced with more information, and then one just
begins all the process anew.
The argument is introspective, and thus suspect, but I could'nt think of a
better (short) one at this time of day...

Well, it's all a bit simplistic (and I'm a bit clumsy after a long day
working, and so are my comments -but not my position, which is very
clear. To me:-), but it seems essentially sound to me;
so, I'll stick with good ol' bivalued (or trivalued) logic.

Or does somebody have a good argument against that position?
-- 
Ch. de Sainte Marie - LIFIA - 40, av. Felix Viallet - 38031 Grenoble - FRANCE
csma@lifia.imag.fr
csma@lifia.UUCP                              "C'est ephemere et c'est moi..."
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