In a message dated 2/18/2002 6:12:37 PM Central Standard Time, cowan@ccil.org writes:Nobody has ever claimed that existential ("some") statements did not Well, some have claimed it for negative particulars ("Some S are not P"). In fact, Aristotle apprears to have done so at least occasionally. <> Lewis Carroll, as I recall, tried to > compromise by giving existential import to "some" statements, but not to > "all" statements (so that, by his scheme, "All unicorns are white" is > acceptable, but "Some unicorns have halitosis" is not). Carroll took the traditional view: both have existential import.> Carroll is a hard case. He published two logic books and wrote a third and through all of them he waffles. Not about "all" and "some", but about "no" and "some... not." The right answer, for all sorts of reasons, is that neither of these has existential import, but are simply the negations of their diagonal opposites, but that was too radical for Dodo, so he tried making "no" free but keeping "some...not ..." existential, then a bit of the oposite and finally a half-hearted return to orthodoxy, with the clear recognition that it was wrong. (The chief virtue of the affirmative- existential, negative -not system is that all the possibilities are definable in it. And, of course, that it is Aristotle's final system.see http://plato.stanford.edu/entries/square/.) <Lojban takes the second view, since both forms can be expressed: one using number + predicate directly (= "All swans"), the other using a bound variable and a relative clause ("All X such that").> At last! Can I take this as the official word? No more changing next week, when I try to rely on this? No smooth-talking logicians muddying the water? And what about the negative cases? Wait! Just to be sure: the first {ro broda} is esistential, the second {ro da poi broda} is not. Right? |