Abstract: Rational norms rely on the notion of identity at a time. It's irrational if one person believes P and also believes not-P, but it's not irrational if one believes P and another believes not-P. But there are puzzle cases where it is unclear whether we have one agent, or two or more: cases of multiple personality, split-brain patients, conjoined twins sharing part of their brain, and octopuses with highly distributed nervous systems. I criticise various criteria for identity at a time and propose a deflationary, conventionalist alternative. Whether to treat the situation as one where we have one agent vs. two or more is to be determined not by underlying metaphysical facts, but rather by our own goals and purposes in using rationally evaluative language.