JC Beall will give a talk titled:"Classical logic is dead. Long live classical logic!" as part of our Colloquium Series on Wednesday, March 6, from 3:30-5:30 in 312 DeBartolo Hall. More information on Dr. Beall can be found on his website.
An account L of logical consequence (henceforth, of logic) is subclassical if and only if i) every classically invalid argument is invalid according to L, and ii) some classically valid argument is invalid according to L. In this talk I argue that the true account of logic is subclassical. (That’s the “classical logic is dead” part.) But — I believe (and so do you) — the vast majority of our true theories are classically closed; they rely on the full force of classical logic. And so they do; and so they should. (This is the “long live classical logic” part.) But there is no tension whatsoever in the death of classical logic together with its apparent ubiquity in our true theories.