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John: > In my earlier posting I had proposed, but not defended, the following > (standard) assignment of existential import: A+E+I-O-. Jorge > counter-proposed A-E+I-O+, but this would break Aristotelian logic, and > reduce the very real distinction between it and modern logic to a nullity > (Reminder: + means that if S, the subject term, is vacuous, the function > is always false, whereas - means there is no such generalization available.) > > It is of the essence of the AEIO functions that they obey the laws > of the Aristotelian square: A and O are contradictory, E and I are > contradictory, A and I are contrary (can't be both true), E and O are > subcontrary (can't be both false), A implies E, I implies O, and A and > E can have their subject and predicate terms interchanged. These things > are only true with the existential-import rules as I stated them [...] > And's point that lo'i ro broda is meaningful even if nothing broda's > is a good one that I do not know how to address at present. A pretty obvious way to address it is not to equate {ro} and A+. Treat {ro} as the cardinality of the set being quantified over. A+ can be done as {ro (fi'u) su'o}. > I note > however that for all such values of broda, the same set (viz. the empty > one) is addressed. I reject all talk of "intensional sets": a set may be > defined by extension or by intension, but set *identity* is defined > by the following tautology: > > ro bu'a ro bu'e zo'u > go lo'i bu'a cu du lo'i bu'e > gi go ro da bu'a gi bu'e > > that is, sets are identical iff whatever is a member of one is a member > of the other, and in particular there is only one null set An "intensional set" is a Kind -- Mr Set of All Broda. Since SL doesn't do Kinds, I accept what you say, but am endeavouring to develop ways to do Kinds in AL. --And.