Personal identity is not always symmetric: even if I will not be a later person, the later person may have been me. What makes this possible is that the relations that are criterial of personal identity—such as memory and anticipation—are asymmetric and ‘count in favor of personal identity from one side only’. Asymmetric personal identity can be accommodated by temporal counterpart theory but not by Lewisian overlapping aggregates of person stages. The question of uncertainty in cases of personal fission (and in Everettian quantum mechanics) is also discussed.
