 Constructivism in metaethics is the view that moral truths are, or are determined by, the outcomes of actual or hypothetical procedures of deliberation or choice. Many who interpret Kant as a constructivist claim that his analysis of “duty” and “good will” reveals that if there are moral requirements then the agents who are bound to them have autonomy of the will (Rawls 1980; Korsgaard 1996; O’Neil 1989; Reath 2006; Hill 1989a, 1989b, 2001; Cureton 2013, 2014; Engstrom 2009). Autonomy, in this sense, means that such agents are both authors and subjects of the moral law and, as such, are not bound by any external requirements that may exist outside of our wills. Instead, we are only subject to moral requirements that we impose on ourselves through the operation of our own reason independently of our natural desires and inclinations. The common error of previous ethical theories, including sentimentalism, egoism and rationalism, is that they failed to recognize that morality presupposes that we have autonomy of the will. These theories mistakenly held that our only reasons to be moral derive from hypothetical imperatives about how to achieve given moral ends that exist independently of the activity of reason itself (for a discussion of Kant’s more specific objections to previous ethical theories, see Schneewind 2009). On these interpretations, Kant is a skeptic about arbitrary authorities, such as God, natural feelings, intrinsic values or primitive reasons that exist independently of us. Only reason itself has genuine authority over us, so we must exercise our shared powers of reasoned deliberation, thought and judgment, guided by the Categorical Imperative as the most basic internal norm of reason, to construct more specific moral requirements. Kantians in this camp, however, disagree about how this rational procedure should be characterized.