My aim is to assess the merits of Korsgaard's rejection of realism as well as the prospects for her practical approach to normativity, and I shall both raise problems for her constructivism and develop a realist response to her central challenge. To make clear what is at stake, I will begin by elucidating the "normative question" that motivates her negative and positive projects alike and by describing the realist and constructivist positions in this debate. Then, in Section II, I will lay out her central critique of realism and go on, in Section III, to explain her current strategy for avoiding the problems she raises for realists. As described more fully at the end of Section III, I will then examine Korsgaard's distinctive approach to normativity by looking at how her practical_problem_solving conception of normativity applies specifically to the principle at the heart of Kantian ethics-the formula of humanity, which she believes must be derived in a purely constructivist fashion in order to be binding. Giving careful attention to such derivations in light of her general account of normativity (Secs. IV-VI) is the best way both to clarify what is really at issue in the debate over normativity and to see concretely how her constructivist approach to deriving normative principles is supposed to deliver what is required by her practical_problem_solving account of binding normative force.