Kant's Grounding Project in The Doctrine of Virtue

In the general introduction to the Metaphysics of Morals where Kant discusses the concept of obligation and its law, he remarks that "the simplicity of this law in comparison with the great and various consequences that can be drawn from it must seem astonishing at first..." (MS 6: 225). In the Doctrine of Virtue, Kant sets forth a system of duties to oneself and to others in which he appears to derive them from the humanity formulation of the CI, thus illustrating the "great and various consequences" that follow from the moral law. Smit and Timmons understand Kant's derivations in the Doctrine of Virtue as purporting not only to justify in the sense of proving or showing true various claims about the deontic status of various types of actions and associated attitudes, but they view the derivations as also purporting explain why the various actions and attitudes have the deontic status Kant claims they have. The aim of their contribution is to (1) provide an interpretation of the humanity formulation which, they argue, is rich in content, and then (2) examine the various derivations featured in the Doctrine of Virtue in order to evaluate their success in providing plausible explanations of the various duties to self and duties to others Kant discusses.