No theory of the moral _ought_ can escape a recognition of a categorical command; but we must choose between the end and the act as that to which the _ought_ applies. If we are sometimes doubtful whether Kant abides at all points by the decision he first makes in this matter, there can be no doubt that he comes to a decision at once in favor of the view that the moral ought applies to a type of act, not to an end this type of act might be calculated to bring about. We should still know our duty if we knew of no such end, we ought still to follow duty if there were no such end. It is in trying to carry through this idea, which we may call the Decalogue idea, of the categorical _ought_, that Kant meets his most serious difficulties. Yet the motives which made him accept and cling to such an interpretation are such as the simplest may grasp--yes, the simpler one is of heart, the more easily may one sympathize with them. In the first place a scientific insight into the means best calculated to bring about an end is obtainable only by study and thought. Even the simple device by which a line may be bisected is not at every one’s disposal, while the highest science has but imperfect means to suggest for accomplishing the ends we most crave. But it seemed to Kant that duty must make a universal appeal, to the poor understanding as clearly as to the richly endowed; morality must be no privilege of the high, but a treasure of the humble. “Be good, sweet maid, and let who will be clever,” is a word of homely counsel that has crept into our language to show how good a Kantian the plain man may be. Or again--but really it is the same thought differently expressed--duty ought to make no hesitating uncertain appeal. No one should have a chance to excuse himself on the ground that he was ignorant of the law. But ignorance of scientific law is the portion of all of us. Alas, if we should have to grope after goodness as we do after wisdom! The intellectuality of pagan Greece might and did contemplate such a state of affairs with equanimity or even with favor. The spirit of Christianity expressed the deep desire of the unintellectual that at least virtue might be theirs for the willing. Kant had a name for any law that was thus universal (that is, applying to everybody) and necessary (that is, free from uncertainty). He called such laws _a priori_; that is, not dependent for their authority upon the slow uncertain gathering of experimental evidence. To him then, the one chance of possessing a moral law _a priori_ lay in the recognition that such a law must in decalogue fashion prescribe a type of act, not an end which might be uncertainly tried for now by truth-telling, now by lying--not an end in short which justified the means so dubiously that it might be taken to justify any means. * * * * *