Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/5/84; site gloria.UUCP Path: utzoo!linus!philabs!cmcl2!seismo!rochester!rocksanne!sunybcs!gloria!colonel From: colonel@gloria.UUCP (Col. G. L. Sicherman) Newsgroups: net.singles Subject: Re: Logic Message-ID: <920@gloria.UUCP> Date: Fri, 12-Jul-85 11:47:05 EDT Article-I.D.: gloria.920 Posted: Fri Jul 12 11:47:05 1985 Date-Received: Mon, 15-Jul-85 00:44:12 EDT References: <259@tove.UUCP> <523@ttidcc.UUCP> <1242@peora.UUCP> Organization: Jack of Clubs Precision Instruments Co. Lines: 29 ["You do not know that I do not know that you do not know you're right."] > EVERYONE should know how to do proofs with quantifiers! For one thing, it's > taught in the introductory CS math courses most places, and for another, > it'll probably be on that test you're going to take, if it's any good... > I mean, everyone should know that > "For all x, y" > is the same as > "It is not the case that there exists an x such that not(y)". > > Among other things, not knowing basic principles of logic like that makes > it hard to argue coherently in everyday discourse. Curiously, professional logicians like Raymond Smullyan take the opposite stand: that logic is a game, and its usefulness is limited to reducing knowledge. I recall one of his examples of how formal logic fails in ordinary discourse: "Good Food is not Cheap Cheap Food is not Good" Should the restorateur have omitted one of the sentences on this signboard? I notice that the weakest arguers on the net are those who cling to logic. -- Col. G. L. Sicherman UU: ...{rocksvax|decvax}!sunybcs!colonel CS: colonel@buffalo-cs BI: csdsicher@sunyabva