This chapter considers what role virtue science can play in moral philosophy. The question is, how much can and should virtue science influence what moral philosophers do? It considers three positions: (1) the strong division position that suggests that virtue science is irrelevant to moral philosophy; (2) the strong constraint position that suggests that virtue science constrains moral philosophy; and (3) the view that virtue science can serve as an important domain for catalyzing the practical value of moral philosophy. The chapter outlines each position and provides reasons for it. It also argues that the two strong positions are incompatible with the work that many normative philosophers do. Finally, it argues that the more moderate catalyst position suggests that, for many, but not all, normative ethicists, the results of virtue science can facilitate the practical aims of their work, and that they should attend and contribute to virtue science.