Path: utzoo!mnetor!uunet!husc6!rutgers!paul.rutgers.edu!cars.rutgers.edu!byerly
From: byerly@cars.rutgers.edu (Boyce Byerly )
Newsgroups: comp.ai
Subject: Re: this is philosophy ??!!?
Message-ID: 
Date: 6 May 88 22:48:09 GMT
References: <4134@super.upenn.edu> <3200014@uiucdcsm> <1484@pt.cs.cmu.edu> <30502@linus.UUCP> <1069@crete.cs.glasgow.ac.uk> <1588@pt.cs.cmu.edu>
Organization: Rutgers Univ., New Brunswick, N.J.
Lines: 50
Keywords: I can't believe it

|In article <1069@crete.cs.glasgow.ac.uk> gilbert@cs.glasgow.ac.uk
|(Gilbert Cockton) writes:
|>logical errors in an argument is not enough to sensibly dismiss it, otherwise
|>we would have to become resigned to widespread ignorance. 
|
|To which acha@centro.soar.cs.cmu.edu (Anurag Acharya) replies: Just
|when is an assumption warranted ? By your yardstick (it seems ),
|'logically inconsistent' assumptions are more likely to be warranted
|than the logically consistent ones. Am I parsing you wrong or do you
|really claim that ?!

My feelings on this are that "hard logic", as perfected in first-order
predicate calculus, is a wonderful and very powerful form of
reasoning.  However, it seems to have a number of drawbacks as a
rigorous standard for AI systems, from both the cognitive modeling and
engineering standpoints.

1) It is not a natural or easy way to represent probabalistic or
intuitive knowledge. 

2) In representing human knowledge and discourse, it fails because it
does not recognize or deal with contradiction.  In a rigorously
logical system, if 

  P ==> Q
  ~Q
   P
Then we have the tautology ~Q and Q.

If you don't believe human beings can have the above deriveably
contradictory structures in their logical environments, I suggest you
spend a few hours listening to some of our great political leaders :-)
Mr. Reagan's statements on dealing with terrorists shortly before
Iranscam/Contragate leap to mind, but I am sure you can find equally
good examples in any political party.  People normally keep a lot of
contradictory information in their minds, and not from dishonesty -
you simply can't tear out a premise because it causes a contradiction
after exhaustive derivation.

3) Logic also falls down in manipulating "belief-structures" about the
world.  The gap between belief and reality ( whatever THAT is) is
often large.  I am aware of this problem from reading texts on natural
language, but I think the problem occurs elsewhere, too.

Perhaps the logical deduction of western philosophy needs to take a
back seat for a bit and let less sensitive, more probalistic
rationalities drive for a while.

	Boyce
	Rutgers University DCS