7

Even Log c Has L mits i i

Liar, Liar

Back when I was in college and my GPA needed a boost, I would seek out
the comforting shelter of the Philosophy Department, which always of-
fered an assortment of introductory courses in logic. The one I took be-
gan by examining this classic syllogism:

All men are mortal.

Socrates is a man.

Therefore, Socrates is mortal.

OK, not exactly a deduction requiring a Sherlock Holmes—but there are
more interesting formulations that might have intrigued even the great
detective. One such syllogism, which did not appear in introductory logic,
initially appears to be a clone of the one above:

All Cretans are liars.

Epimenides is a Cretan.

Therefore, Epimenides is a liar.