In this article, Christine Korsgaard addresses the issue of the moral standing of nonhuman animals. She evaluates arguments for and against regarding nonhuman lives in light of the Kantian notion of being an “end in oneself,” ultimately arguing that animals are ends in themselves by virtue of the way in which they pursue ends that they evidently regard as absolutely important. For this reason, Korsgaard denies that animals’ lives do not matter to them. But she qualifies this by adding that human lives differ from nonhuman lives by virtue of mattering to humans in a distinctively human way. Uniquely human self-consciousness makes it the case that we identify ourselves with normative standards of success and failure, in terms of consciously embraced roles and relationships. Nonhumans do not reflectively invest themselves in ideals in the same way. The implication is not that nonhuman lives do not matter to animals, nor even that anything is missing from an animal’s life. Humans and nonhumans are merely different kinds of beings, but both are entitled to moral recognition as subjects of lives that matter in their own right.