Three Models of Natural Right: Baumgarten, Achenwall, and Kant

In the Metaphysics of Morals, Kant locates the Rechtslehre in the realm of the “systematic knowledge of the doctrine of natural right (Ius naturae).” However, Kant in a profound shift there redefines the concept of ius naturae: the (moral) right of nature becomes the law of freedom, and the doctrine of natural right becomes “the metaphysical doctrine of right.” This chapter examines Kant’s critical analysis of two previous models of natural right, those belonging to Baumgarten and Achenwall. In contrast to Kant, these highlight the normative link between right principles and a natural end, as well as the role of God as the author of moral laws, both absent in Kant. While Kant’s concept of right adopts Achenwall by dissociating right from ethics and associating it with the power to coerce, he retains Baumgarten’s notion that a rational doctrine of right forms part of a broader systematic doctrine encompassing the whole system of duties.