Date: Wed, 3 Dec 1997 12:54:36 -0500 (EST) Message-Id: <199712031754.MAA08089@locke.ccil.org> Reply-To: bob@rattlesnake.com Sender: Lojban list From: bob@MEGALITH.RATTLESNAKE.COM Subject: Re: universe of discourse X-To: LOJBAN@CUVMB.CC.COLUMBIA.EDU To: John Cowan In-Reply-To: <526E20D88@mail-gw.uclan.ac.uk> (message from And Rosta on Wed, 3 Dec 1997 13:19:31 GMT+0) X-Mozilla-Status: 0011 Content-Length: 2150 X-From-Space-Date: Wed Dec 3 12:54:51 1997 X-From-Space-Address: LOJBAN@CUVMB.CC.COLUMBIA.EDU > > What is a universe of discourse? > > That topic within which you and your interlocutor are talking. To which a.rosta@uclan.ac.uk responded: This is how I understood it. So if you're in the garden and say "every flower is yellow", it might mean "every flower in the garden". Yes. Going by what you say, a universe of discourse is then not the same thing a s a possible world (contra Lojbab). A possible world may be a universe of discourse, or maybe not; a universe of discourse may not be a possible world, it may be an impossible world. Lojbab seemed to be saying that it is possible to construct a world containing only even numbers. This is what I cannot conceive of. I can of course easily understand a discussion focused entirely on even numbers, where odd numbers are irrelevant, and where {ro namcu} might be intended to mean "all even numbers". It may be that you and he are using the word `construct' in different ways. I interpret your phrase in the above paragraph, "... a discussion focused entirely on even numbers..." as *constructing* such a world, hence your saying words that would agree with Lojbab if you interpreted what you say the way I do. Certainly, also, at one time I understood my math textbook as telling me how to _construct_ a universe of even numbers without there being odd numbers at all. (Every entity has a successor; the entities interchange among themselves according to the following rules; that sort of thing. No, this is not the jargon that should be used; I have forgot most of it.) This latter process would fit your meaning of the word `construct'. The problem suffered by an ordinary human is to forget knowledge about numbers that were learned years ago but don't apply in the specific circumstances. A mathematician will forget, so as not to get confused (or at least give a good appearance of forgetting, so as to create a memory for the student [`lo tadni'? `loi tadni'?]). -- Robert J. Chassell bob@rattlesnake.com P. O. Box 693 bob@ai.mit.edu Stockbridge, MA 01262-0693 USA (413) 298-4725