content of experience, it is empty and useless. The understanding must always be a synthesis of a manifold. On the other hand, the practical reason needs no content. It is sufficient in itself. It need not be obeyed anywhere nor have any concrete content in the phenomenal world. It has no reference to what is but to what _ought to be_. The world of morality and the world of phenomena are different worlds. The world of morality is absolute reality, while the world of knowledge is only relative. The world of morality is the unconditioned, while that of knowledge is conditioned by experience. Morality applies not only to human beings, but to all rational beings, if any other rational beings exist. Knowledge, however, belongs to human beings alone. The moral law has not its home in the empirical, but in the transcendent, intelligible world, which to knowledge would be the world of Things-in-Themselves. =The Moral Law and the Two Questions concerning It.= The questions of the _Critique of Practical Reason_ are the same as those of the _Dialectic_: (1) Is there any _a priori_ synthesis? This is not the question of the _Analytic_, which is, How is an _a priori_ synthesis possible? (2) Can the human being be moral and still be a part of the world of phenomena and necessity? We shall now comment on the first of these problems. If the will has validity, it must be the expression of some universal and necessary principle. Can we find any such _a priori_ principle in our consciousness? 1. _The First Question concerning the Moral Law._ If we search our consciousness, we shall find that there are two classes of incentives to action. The first are called the inclinations, or perhaps better the impulses. We may will because we desire to gain something, of use, pleasure, perfection, etc. Such an act of will is dependent upon the object that arouses it. Such an act of will would not be an example for any one else; for the circumstances that called it forth would be likely to be different in each case. For example, there is no consensus as to pleasure among individual men; and what is pleasant to one is unpleasant to another. The same is true about objects of use and ambition. In all these matters judgment does not help us in making our selection, for people who are the most discriminating often are the most unhappy and useless. All these things are indeed goods, but they are goods for the moment――goods that are dependent on something else, and not goods in themselves. They are legitimate ends enough, but they are so transitory that they cannot be valid. It is evident that when the will is governed by inclination, it is governed by an empirical (_a posteriori_), and not by a universal and necessary (_a priori_) principle. Such empirical principles are called by Kant hypothetical imperatives.