Like previous theorists of natural law, Kant believes in the possibility of a rational theory of ius, but also claims that the very concept of ius naturae and the method of investigation of its principles must be thoroughly reformulated. I will maintain that Kant solves the methodological problem of natural law theories by stating that a rational doctrine of Right concerns pure rational knowledge. Right must be conceived as a metaphysical doctrine in which its principles and laws are determined a (...) priori. By conceiving the idea of a “metaphysics of morals” and linking Right with it, he finds a way both to conserve the notion of ius naturae ) and to purify it from any empirical or anthropological element. (shrink)