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