Criticism of Locke's account of personal identity has proceeded cumulatively. Three years after the publication of the chapter “Of Identity and Diversity”, John Sergeant raised an objection which, in Bishop Butler's hands, was to become famous as the dictum that “one should really think it self-evident that consciousness of personal identity presupposes, and therefore cannot constitute, personal identity: any more than knowledge, in any other case, can constitute truth, which it presupposes”. Berkeley added, in effect, that when consciousness is taken (...) to be the criterion of personal identity, one must admit that a man conscious of segments of his life at some times and not at others both is — because “conscious of” states a transitive relation — and is not — because of lack of consciousness—the same person. (shrink)