From: utzoo!decvax!yale-com!leichter Newsgroups: net.math Title: Re: I am trying to comprehend Article-I.D.: yale-com.824 Posted: Mon Feb 7 18:44:42 1983 Received: Wed Feb 9 03:43:31 1983 References: ihuxr.321 The Axiom of Comprehension - a terrible name, that - lets you build arbitrary subsets of sets you already have. The axiom as you wrote it is also qualified by (A z A phi). Suppose there was a univeral set. Let z be this set, and let phi(x) = ~x