From @uga.cc.uga.edu:lojban@cuvmb.bitnet Wed May 31 00:00:12 1995 Received: from punt2.demon.co.uk by stryx.demon.co.uk with SMTP id AA3183 ; Wed, 31 May 95 00:00:08 BST Received: from punt2.demon.co.uk via puntmail for ia@stryx.demon.co.uk; Tue, 30 May 95 11:38:44 GMT Received: from uga.cc.uga.edu by punt2.demon.co.uk id aa14584; 30 May 95 12:37 +0100 Received: from UGA.CC.UGA.EDU by uga.cc.uga.edu (IBM VM SMTP V2R2) with BSMTP id 7132; Tue, 30 May 95 07:35:47 EDT Received: from UGA.CC.UGA.EDU (NJE origin LISTSERV@UGA) by UGA.CC.UGA.EDU (LMail V1.2a/1.8a) with BSMTP id 8758; Tue, 30 May 1995 07:35:47 -0400 Date: Tue, 30 May 1995 07:35:36 -0400 Reply-To: Logical Language Group Sender: Lojban list From: Logical Language Group Subject: non-existance predications X-To: lojban@cuvmb.cc.columbia.edu To: Iain Alexander Message-ID: <9505301238.aa14584@punt2.demon.co.uk> Status: R >If you are saying, There are no fairies, you CAN'T say lo crida na >zasti, because that's logical contradiction. IMHO. I don't know the >current consensus on this. Since the "na" has scope of the entire bridi, there is no problem. It converts to "naku lo crida zo'u lo crida cu zasti" "It is not the case that: for something that is a fairy, that fairy exists." The problem arises if you have a selbri which requires non-existance. Let us say that "nalzasti" is such a selbri (at one time "xanri" had this meaning). Then: "lo crida cu nalzasti" could cause a problem if there are no such things as fairies. I'm not sure it does, because for me, the equivalent "lo crida zo'u lo crida cu nalzasti", the prenexing in the "lo crida" form contains no stronger claim of existence than it does in the main text. But in the "da poi" form there is a clear problem: da poi crida zo'u da nalzasti clearly is false because you have postulated the existance of da in the prenex, then said that da not-exists, contradicting yourself. Question for pc then: in standard logic, does a non-quantified variable in the prenex claim its existance, or merely cite a variable without claiming reference. If the latter, then we have identified a slight, almost trivial, difference between lo broda and da poi broda. lojbab