Formal principles and the form of a law

One aim of the Critique of Practical Reason is to establish that reason alone can determine the will. To show that it can, it suffices to show that there are practical principles given by reason alone – what Kant terms ‘practical laws’, or (roughly) requirements of reason on action. Chapter I of the Analytic accomplishes this aim by arguing that the moral law is an authoritative practical principle given as a ‘fact of reason’. The chapter begins in section 1 with a ‘Definition’ (Erklärung) of a practical law as a practical principle that..