 Kant gives several formulations of the Categorical Imperative, which he regards as equivalent (G 4: 421, 429, 431, 433); but ultimately, it is the requirement that in deliberating, we test our motives by considering whether the principle they express can be endorsed as a universal law, a principle that applies to and binds all agents endowed with rational capacities. Kant is committed to the “constitutivist view” that the source of the categorical force of moral obligations lies in the constitutive features of rational agency (Rawls 2000: 263–265; O’Neill 1989a, Korsgaard 1996a: 236ff). We will return to this point in  section 7.