Abstract

This Article critically discusses Clifford Williams’ claim that the A-theory and B-theory of time are indistinguishable. I examine three considerations adduced by Williams to support his claim that the concept of time essentially includes transition as well as extension, and argue that, despite its prima facie plausibility, the claim has not been adequately justified. Williams therefore begs the question against the B-theorist, who denies that transition is essential. By Williams’ own lights, he ought to deny that the B-theory is a (realist) theory of time; and thus his claim that A-time and B-time do not differ significantly should be rejected.