In his “Grundlegung zur Metaphysik der Sitten” (The Foundation of the Metaphysics of Ethics) and “Kritik der praktischen Vernunft” (Critique of Practical Reason) _Kant_ sought to establish _autonomy in moral life_ and action. Man himself, his practical reason, is the ultimate foundation of all moral obligation; did man lead a good life out of obedience to God it would be a heteronomy unworthy of the name of “moral.” “The autonomy of the will,” he teaches, “is the sole principle of all moral laws and the duties allied to them; all arbitrary heteronomy, on the contrary, far from having any binding force, is contrary to the principle of morality of the will” (Kritik der prakt. Vern., Elementarlehre, I, 1, 4. Lehrsatz). Or, as amplified by a faithful interpreter of the master: “In the moral world the individual should be not only a member but also a ruler; he is a member of the moral order when he obeys its law; he is its ruler when he enacts the law.... The distinction between autonomy and heteronomy separates true from false ethics, the system of _Kant_ from all other systems. All moral systems, except that of _Kant_, are based on the principles of heteronomy; they can have no other. And critical philosophy was the first to grasp the principle of autonomy” (_Kuno Fischer_, Geschichte der neuen Philosophie, IV, 2d ed., 1869, p. 114 _seq._). _Kant’s_ just man no longer prays “Thy will be done”; he identifies the law with himself. _Nietzsche’s_ transcendental man is seen in the background. _Autonomy of thought_ is the result of the “Critique of Pure Reason,” and in spite of its inconsistency of expression, its involved sentences, its extremely tiresome style, it is and will long continue to be the text-book of modern philosophy. According to _Kant_ our cognition consists in our fashioning the substance of our perceptions and reasoning after innate, purely subjective, views and conceptions. Time and place, and especially the abstract notions of existence and non-existence, necessity, causality, substance, have no truth independent of our thought; they are but forms and patterns according to which we are forced to picture the world. Their first matter is supplied by sense experience, such as sound, colour, feeling; but these, too, according to _Kant_, are not objective. Nothing then remains to our cognition that is not purely subjective, having existence in ourselves alone. Our cognition is no longer a reproduction, but a creation of its object; our thought is no longer subject to an external truth that may be forced upon it. “Hitherto,” says _Kant_, “it has been generally supposed that our cognition must be governed by objects.... Let us see if we cannot make better headway in the province of metaphysics by supposing that objects must be governed by our cognition” (Kritik der Reinen Vernunft, Vorrede zur zweiten Ausgabe).