Introduction

Kant's Groundwork of the Metaphysics of Morals inaugurated an approach to moral philosophy so original it is designated “Kantian Ethics”, including work prizing fidelity to Kant's own views and work inspired primarily by his views. Kant's moral philosophy advocates a distinctive fundamental moral principle and develops a unique system of moral principles, centring on the key terms “practical reason”, “law”, “maxim” and “categorical imperative”.

Kant worked with the traditional classification according to which “moral philosophy” is a genus, with two proper, coordinate species: theory of justice [Rechtslehre] and ethics [Tugendlehre]. Twentieth-century anglophone moral philosophers, however, commonly regard ethics as the primary discipline, demoting social, political and legal philosophy to a mere corollary to ethics. The oddity of this recent conception is highlighted by the fact that central ethical issues about individual action and virtue can be nothing but theory, if even that, without a significant degree of public peace, security and stability, which require principles and institutions basic to theory of justice. This reminder underscores why Kant's Groundwork must be considered within the corpus of his major writings in practical philosophy, The Critique of Practical Reason, The Metaphysics of Morals and much of his Religion within the Bounds of Reason Alone, along with his several essays on ethics and politics. More importantly, Kant knew first hand that whoever inaugurates a new kind of systematic enquiry must begin with an initial conception of the proposed system, which is inevitably revised and improved through its development (CpR A 834/B 862). This holds true of Kant's mature, properly Critical moral philosophy, first enunciated in the Groundwork but only completed in much later works.