Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!husc6!rutgers!sri-spam!ames!ucbcad!ucbvax!cogsci.berkeley.edu!kube From: kube@cogsci.berkeley.edu (Paul Kube) Newsgroups: sci.philosophy.tech Subject: Incompleteness (was: Re: Uncertainty in life) Message-ID: <19216@ucbvax.BERKELEY.EDU> Date: Mon, 1-Jun-87 21:14:41 EDT Article-I.D.: ucbvax.19216 Posted: Mon Jun 1 21:14:41 1987 Date-Received: Wed, 3-Jun-87 04:07:02 EDT References: <6762@mimsy.UUCP> <3977@sdcc3.ucsd.EDU> <8135@ut-sally.UUCP> <1192@epimass.EPI.COM> Sender: usenet@ucbvax.BERKELEY.EDU Reply-To: kube@cogsci.berkeley.edu.UUCP (Paul Kube) Organization: University of California, Berkeley Lines: 23 In article <1192@epimass.EPI.COM> jbuck@epimass.EPI.COM (Joe Buck) writes: >In article <8135@ut-sally.UUCP> turpin@ut-sally.UUCP (Russell Turpin) writes: >>Godel's *incompleteness* theorems simply say that your >>hypothetical logician, if consistent, might come across >>unprovable statements. In the first order predicate calculus, for >>example, there are fully quantified statements that can neither >>be proven or disproven. > >Godel's first incompleteness theorem states that you WILL, not MIGHT, >come up with unproveable statements if your axiom system is powerful >enough. The upshot of Goedel's incompleteness theorem is the unprovability of necessarily true statements, i.e., statements true in every model, for sufficiently powerful systems. That there are *some* statements your system can't prove is a good thing: but this is the requirement of consistency, not completeness. First order predicate calculus is both consistent and complete. / / / / --Paul.