What is the sanction of morality? Why should a man be virtuous? The answer depends upon the answer to the previous question: What is it to be virtuous? If, for example, virtue means all such conduct as promotes happiness, the motives to virtuous conduct must be all such motives as impel a man to aim at increasing the sum of happiness. These motives constitute the sanction, and the sanction may be defined either as an intrinsic, or as an extrinsic, sanction; that is, it may be argued either that virtuous conduct leads to consequences which are desirable to every man, whether he be or be not virtuous; or, on the other hand, that virtuous conduct as such, and irrespectively of any future consequences, makes the agent happier. The problem is, thus, to find a scientific basis for the art of conduct. The "sanction" must supply the motive power by which individuals are to be made virtuous. This is, for the practical moralist, the culminating point of all ethical inquiry. Now there is, by our theory, a necessary and immediate relation between social vitality and morality. But it does not follow that there is the same intimate connection in the individual case. The sacrifice of some of its members may be essential to the welfare of the society itself. We have, then, to answer three questions: first, whether the virtuous man, as such, is happier than the vicious; second, whether it is worth while, on prudential grounds, for the vicious man to acquire the virtuous character; and third, whether it can be worth while, in the same sense, for the vicious man to observe the moral law.