Volume 1: After pointing out the errors involved in ethical naturalism, the author proceeds to refute Kant's teaching that the moral law, because discerned a priori, issues from Reason and is a self-legislation of the rational will. Against this view Plato's position is upheld, that all values and the Ought constitute an objective, absolute realm of essences which man discovers a priori, but which no more emanate from Reason than do the principles of mathematics and logic.