Cool Logic

Dean McHugh (ILLC)

Paradoxical Predicates

December 2nd at 17:30, in F1.15

Once upon a time there was an evil trickster. The trickster lived in the city of Logopolis, and loved nothing more than wondering how to deceive its citizens. One day, the trickster imagined a very mischievous predicate – called 'self-contradictory' – subject to the stipulation that anything is self-contradictory if and only if it is not self-contradictory. The trickster told anyone who would listen about this predicate. For, given that everything is either self-contradictory or not self-contradictory, if something, anything, is self-contradictory, it follows that is not; and it if it is not, then it is. So supposing that everything is either self-contradictory or not leads us to conclude that everything is both self-contradictory and not. The trickster laughed and laughed. To find out how the citizens responded, though, you have to come to the talk!