What is it to understand why p? This project will argue that understanding why p is factive, but also includes a "grasp" of the relationship between p and its explanation q. This "grasp" is similar to knowledge how. It will be shown that understanding why, in this sense, is valuable both for its own sake and for its role in acting for the right reasons. It also has implications for moral virtue and moral expertise. An "intellectualist" account of moral virtue is proposed and defended, according to which a morally virtuous person can explain why her action is morally right. This project also aims to show ways in which the relationship between a moral expert and a non-expert is changed when we focus on acquiring understanding why rather than knowledge. Finally, this new conception of understanding will be used to solve a puzzle in aesthetics about the status of aesthetic testimony.