 The argument for the circularity of the memory criterion went like this. Suppose we think of the memory criterion as giving what would be later called an analysis of A being the same person as B. If so, we are invited to analyze A being the same person as b in terms of A remembering enough of what happened to B. But any plausible analysis of A remembering what happened to B will mention, in the analysans, A being the same person as B.