From cbmvax!uunet!Think.COM!gls Thu Jun 13 15:03:42 1991 Return-Path: Date: Thu Jun 13 15:03:42 1991 Return-Path: From: Guy Steele Message-Id: <9106131824.AA21917@strident.think.com> To: cbmvax!snark.thyrsus.com!cowan Cc: lojban-list@snark.thyrsus.com In-Reply-To: John Cowan's message of Thu, 13 Jun 91 11:04:48 EDT Subject: names as predicates Status: RO From: cbmvax!snark.thyrsus.com!cowan@uunet.UU.NET (John Cowan) Date: Thu, 13 Jun 91 11:04:48 EDT > (My skepticism about the dichotomy of names and predicates > is related to my distrust of equality as a primitive notion > in predicate logic. I suspect that the abstract notion of > equality misleads us concerning the nature of perception; > in this view, equality is properly applied--if at all--only > to abstractions and not to physical objects.) I don't understand this. (BTW, by "equality" I assume you mean "identity"; what is expressed by the Lojban word "du" or the Old Loglan equivalent "bi".) Why shouldn't identity be applied to physical objects? It is simply that relationship which holds only between a thing and itself: the smallest reflexive relation, in Kripke's definition. On Tuesdays and Thursdays I am willing to defend the position that the notion of "thing" is not well-defined as applied to physical objects. It may be ontologically unjustified to build the assumption that it is well-specified into the deep structure of Lojban. Kripke's definition begs the question, for the very definition of relation R being "reflexive" is that for all x and y, x=y implies xRy. (I won't accept a definition that reads, "for all x, xRx" because that merely embeds the implicit use of equality in the notation.) I would also like to take this opportunity to retract some of what I wrote to Steve Rice a while ago. He stated that in Institute Loglan predicates and identities were distinct, and that "bi" did not express a predicate. I half agreed that "du" did not either, being influenced by a notion that "du" expressed identities by definition. However, the use of "du" as mathematical equality ("bi" is also so used) shoots that one down: 2 + 2 and 1 + 3 are equal not by definition but because they are the same object, the number 4. The statement: li re su'i re du li pa su'i ci the-number 2 + 2 = the-number 1 + 3 represents a truth, as does its exact Institute Loglan equivalent "lio to poi to bi lio ne poi te". Its truth is exactly on a par with the truth of any other true predication. Right. So if I can say mi du la glis. then why can't I say mi la glis. ?