It is widely affirmed that human beings have irreplaceable valuable, and that we owe it to them to treat them accordingly. Many theorists have been drawn to Kantianism because they think that it alone can capture this intuition. One aim of this paper is to show that this is a mistake, and that Kantianism cannot provide an independent rational vindication, nor even a fully illuminating articulation, of irreplaceability. A further aim is to outline a broadly Aristotelian view that provides a more fitting theoretical framework for this appealing conception of human value. This critique of Kantianism extends to contemporary theorists with a broadly Kantian orientation, including Christine Korsgaard, Stephen Darwall and John Rawls. The problem with these views, at heart, is that they attempt to ground morality in respect alone. Yet it is love, not respect, that brings irreplaceability into view. The paper closes with a sketch of a virtue-theoretic theory that follows Aquinas in taking love to be a master virtue that refines the other virtues so as to ensure a continuous and practically efficacious sensitivity to the irreplaceable value of fellow human beings.
