Kant’s Conception of Natural Right

Commenting on Aristotelian passage, St. Thomas points out that the aim of moral philosophy is not simply the contemplation of truth, but action. Natural law, in its Thomistic version, at least, is not a law or order already existing in nature, taken as untouched by human reason, which this reason can but discover or interpret by purely receptive means. In short, the doctrine of natural law tells nothing new about practical or moral knowledge and throws no new light on practical reasoning. As far as knowledge is concerned this doctrine lacks any practical value. The attempt to explain the morality of actions in terms of law and obligation as central categories of ethical reflection has a long tradition, part of which is allegedly Thomistic. It is logical that within this tradition the idea of natural law, to which St. Thomas only devotes a single Question in the Summa, should have become the keystone of moral philosophy.