Abstract
The paper presents considerations that weigh against one or another version of the psychological continuity theory of personal identity over time. Such Locke-like theories frequently go wrong, it is argued, in not formulating precisely how the psychological states of an individual person are related diachronically, in failing to capture a truly appropriate causal connection between later and earlier psychological states, and in claiming support from particular cases. In addition, the paper offers examples and other considerations that support an alternative, biological continuity theory according to which you and I are each identical with a human organism.