Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!ames!hao!gatech!udel!princeton!mind!greg From: greg@mind.UUCP (greg Nowak) Newsgroups: sci.philosophy.tech Subject: Re: Classifying the Axiom of Choice Message-ID: <1938@mind.UUCP> Date: 25 Feb 88 20:15:53 GMT References: <7123@agate.BERKELEY.EDU> <8768@sunybcs.UUCP> <9734@shemp.CS.UCLA.EDU> <1937@mind.UUCP> Reply-To: greg@mind.UUCP (greg Nowak) Organization: Cabal of Fools Lines: 31 In article <9734@shemp.CS.UCLA.EDU> hbe@math.ucla.edu (H. Enderton) writes: >In article <8768@sunybcs.UUCP> rapaport@gort.UUCP (William J. Rapaport) writes: >>I guess you [weemba@garnet.berkeley.edu have not read Kant. All mathematical >>propositions are synthetic apriori for him. By that, I'd take the Axiom of >>Choice as synthetic apriori, too. > >Kant's classification of mathematical truths as synthetic a priori seems >in light of Godel to be more wrong than right. The a priori statements >form merely a recursively enumerable set, and hence cannot include even >all the true statements of arithmetic. I think that the analytic >a posteriori is an unjustly neglected category in the philosophy of >mathematics. I am not sure, however, that I want to put the axiom of >choice into it. The "analytic a posteriori" category is neglected because it is EMPTY. Anything which is analytic, i.e. true for semantic reasons, is a priori (independent of experience) -- even if the terms refer to objects we usually encounter with experience. Thus "all bachelors are male" is an analytic a priori statement, because it is true by the meanings of the words -- even though we DO have real-world experience of males and bachelors, we NEED not to judge the truth of the statement. "The sky is blue" is a synthetic a posteriori proposition, because nothing in the definition of what a sky is requires it to be blue. The suggestion about enumerating the set of propositions would seem to be more applicable to the *analytic* propositions than the a priori ones, thus strengthening the claim that there are synthetic a priori propositions. -- greg