Abstract

According to Kant, the supreme principle of morality is: “act only according to that maxim through which you can at the same time will that it become a universal law” (G 4:421). This principle has come to be known as the Formula of Universal Law (“FUL”). Few philosophers believe it succeeds. But, I argue, few philosophers have understood what FUL means. This dissertation offers a full defense of FUL. It is, in fact, the supreme principle of morality—and it can successfully derive a viable theory of permissible action and virtuous willing. Kant was right. Chapter 1 considers FUL’s role in relation to Kant’s subsequent formulations of the Categorical Imperative and the broader architectonic of duty he sets up in the Metaphysics of Morals. I argue that Kant’s formulations are equivalent insofar as they are each expressions of the very same moral principle. And I suggest that FUL’s two tests correspond to Kant’s later distinction between duties of right and duties of virtue. Thus, FUL’s contradiction-in-conception test can be used to derive duties governing permissible action, and FUL’s contradiction-in-the-will test can be used to derive duties governing virtuous willing. This sets up the framework for the remainder of the dissertation. Chapters 2 and 3 together interpret and defend Kant’s account of permissible action. In Chapter 2, I argue that we should fundamentally reconceive of the nature and purpose of Kant’s permissibility criterion. Kant’s contemporary interpreters have adopted too psychologistic an account of the maxim. Kantian maxims have little to do with the motivating principles of actual agents. Relying on Kant’s historical context and his account of maxims in rational agency, I argue that FUL tests means-end principles which describe act-types. When its permissibility test is applied to such principles, it can viably derive general duties. Chapter 3 continues this positive account of Kant’s permissibility test and defends it from common objections. I argue that the contradiction-in-conception test rejects an act-type when it would be inconceivable for all rational agents to be directly governed by the type’s means-end imperative as a universal practical law. So understood, FUL condemns act-types because: (1) they are hypocritically self-serving, (2) they inflict agential harm on other agents, or (3) they inflict self-harm motivated by self-love. I defend FUL’s derivations against such act-types against common criticisms, such as that they are circular or overbroad. Turning to prominent objections against Kant’s account of permissible action, I then argue that FUL correctly rules out all and only impermissible actions. Moreover, its conclusions are both nuanced and normatively defensible. In Chapter 4, I turn to Kant’s virtue ethics. I begin by considering the demands of Kantian virtue. I argue that we should reject accounts on which duties of virtue are merely less restrictive duties governing permissible action. Instead, I argue, they represent genuinely virtue-ethical requirements to promote morally worthy ends, namely, the ends of our own perfection and others’ happiness. I show that all of Kant’s duties of virtue can ultimately be traced back to one of these required ends. Then, I argue that FUL’s contradiction-in-the-will test can successfully derive our positive obligation to set the ends of virtue. I conclude that FUL is successful not only as a standard of permissibility, but also as the supreme principle of virtue.