 First, suppose a young student is fined for overdue library books. Later, as a middle-aged lawyer, she remembers paying the fine. Later still, in her dotage, she remembers her law career, but has entirely forgotten not only paying the fine but all the other events of her youth. According to the memory criterion the young student is the middle-aged lawyer, the lawyer is the elderly woman, but the elderly woman is not the young student. This is an impossible result: if x and y are one and y and z are one, x and z cannot be two. Identity is transitive; memory continuity is not.