 We are both moral and embodied agents, persons and organisms. We move in the space of reasons, answerable to rules of morality and rationality, as well as a space of causes, governed by the laws of nature. How are these two aspects of our lives linked? This question is too big to answer here. But PAP, if true, is one piece of the puzzle. Our status as persons is enabled by a kind of power we exercise in the world of causes, namely, the power to choose among alternative courses of action. In this way, our principle links a normative feature of our lives to a casual feature.