INTRODUCTION: THE MAIN TOPICS OF SECTION II
Of the three sections of the Groundwork, Section II is by far the longest and most sweeping in scope. It is in this Section that Kant finally identifies the categorical imperative as the supreme law of morality. He discusses a number of different formulations of the law, and he explains the sense in which the law commands categorically. In addition, he considers various applications of the moral law. He indicates in a preliminary way how particular duties may be derived from it. Kant also sets out to deepen our understanding of the central character of Section I, the good will. He further clarifies the way in which the motivational ground of the good will differs from other motivational grounds. As we know, the good will acts from duty. In acting from duty, it allows the categorical imperative to govern its will. We learn in Section II that the categorical imperative is a law rational agents give themselves. Kant argues that rational agents are able to give themselves law in virtue of their remarkable capacity of self-determination or autonomy.
DUTY IS NOT A CONCEPT OF EXPERIENCE (406–412)
The first sentence of Section II reminds us of a central claim of the Groundwork, namely, that the concept of duty is not a concept of experience. We first encountered this claim in Kant's Preface. A “metaphysics” of morals is “indispensably necessary,” he asserted there, precisely because morality cannot rest on anything empirical (389).