In this paper, I defend an interpretation of Kant’s Singularity Thesis: the claim that the formulae of the Categorical Imperative are in fact representations of a single, underlying law. I proceed by answering two questions: (1) How should we state the underlying law? And (2) How can we best understand the relationship between the formulae and this law they supposedly represent? My account focuses on the concept of rational agency and how Kant develops it in the Groundwork. I will argue that the formulae are three ways of expressing, thinking about, or applying the Categorical Imperative — understood as Kant’s statement of the supreme principle of morality — corresponding to three features of rational agency.