Richard Kraut's neo-Aristotelian account of well-being, Developmentalism, aspires to explain not only which things are good for us but why those things are good for us. The key move in attempting to make good on this second aspiration involves his claim that our ordinary intuitions about what is good for a person can be successfully explained and systematized by the idea that what benefi ts a living thing develops properly that living thing's potentialities, capacities, and faculties. I argue that Kraut's understanding of such proper development plays no serious constraining role in shaping the details of the account. If this is correct, Developmentalism lacks the potential to explain or vindicate the intuitions about what is good for us that it champions. In effect, Kraut offers us a list of things that he claims benefits a person, but he lacks a theory of what those things have in common such that they benefit him.