The concept of the person is widely assumed to be indispensable for making a rights claim. But a survey of the concept’s appearance in legal discourse reveals that the concept is stretched to the breaking point. Personhood stands at the center of debates as diverse as the legal status of embryos and animals to the rights and responsibilities of corporations and nations. This Note analyzes the evidence and argues that personhood is a cluster concept with distinct components: the biological concept of the human being, the notion of a rational agent, and unity of consciousness. This suggests that it is the component concepts—not personhood itself—that are indispensable for grounding our moral and legal intuitions about rights. The component concepts also promote greater systematicity and coherence in legal reasoning. The Note concludes by suggesting some implications of this view for applied legal reasoning.