Abstract

This chapter considers the centrality of principles in Kant’s moral philosophy, their distinctively ‘Kantian’ character, why Kant presents a ‘metaphysical’ system of moral principles and how these ‘formal’ principles are to be used in practice. These points are central to how Kant thinks pure reason can be practical. These features have often puzzled Anglophone readers, in part due to focusing on Kant’s Groundwork, to the neglect of his later works in moral philosophy, in which the theoretical preliminaries of that first essay are properly articulated. In part, however, these puzzles stem, directly or indirectly, from Kant’s opposition to moral empiricism, which is bound to puzzle Anglophone readers, whose default orientation is empiricist. Accordingly, particular attention is paid to Kant’s reasons for rejecting moral empiricism and for developing an alternative to it, to Kant’s account of how his universalization tests serve as criteria of morally obligatory, permissible or prohibited actions and to his account of what is morally wrong with actions which violate those criteria. Examining these points provides a compelling synopsis of Kant’s system of moral principles, centring on the key terms ‘practical reason’, ‘law’, ‘maxim’ and ‘Categorical Imperative’.