The metaphysics of morals as a system of duties: the distinction between right and ethics in Thomasius and Kant

This paper presents a brief contribution to the study of the historical sources of Kant's practical philosophy, discussing the Kantian project of a metaphysics of morals as a doctrine of duties in the context of German natural law of the 17th and 18th centuries. At first, Christian Thomasius' distinction between internal and external obligation is exposed as the basis for the differentiation between legal duties and ethical duties. Then the Kantian opposition between a doctrine of right and a doctrine of virtue is discussed against the background of Alexander Baumgarten's and Gottfried Achenwall's reception of Thomasius.