For most if not all of the systems of classification commonly proposed are based upon some metaphysical theory or some theological doctrine. To adopt any one of these would be tantamount to adopting the theory or theology on which it is founded; would be equivalent to introducing surreptitiously a particular philosophy or creed into the minds of the pupils; and this would be a plain departure from the unsectarian principle to which we are pledged. Thus, Plato's fourfold division of the virtues into the so-called cardinal virtues of temperance, courage, justice, wisdom, is based on his psychology. Aristotle's division of the virtues into dianoetic and what he calls ethical virtues is clearly dependent on what may be termed Aristotle's intellectualism--i. e., the supreme importance which he assigns to the functions of the intellect, or [Greek: nous], in the attainment of the perfect life. Kant's division of duties into complete and incomplete is an outgrowth of the ideas developed in his Critique of Pure Reason; the philosopher Herbart's fivefold classification reflects his metaphysical theory of reality; while the systems of ethical classification which are to be found in theological handbooks betray still more clearly the bias of their authors. We can, I think, find a simple way out of this difficulty by proceeding in the following manner: Let us take for our guidance the objects to which duty relates, and disregard the sources from which it flows. It is conceded on all hands that every one is to himself an object of duty, that he has certain duties to perform with respect to himself, as, for instance, the duty of intellectual development; furthermore, that every person owes certain duties to his fellow-men generally, in virtue of the fact that they are human beings; again, that there are special duties which we owe to particular persons, such as parents, brothers, and sisters; finally, that there are certain duties, into which, so to speak, we are born, like the ones last mentioned, and others which we can freely assume or not, like the conjugal duties, but which, once assumed, become as binding as the former. Thus the very structure of human society suggests a scheme of classification. And this scheme has the advantage of being a purely objective one. It keeps close to the facts, it is in harmony with the unsectarian principle, and it is perfectly fair. It leaves the problem of first principles entirely untouched. That we have such duties to perform with respect to self and others, no one questions. Let philosophers differ as to the ultimate motives of duty. Let them reduce the facts of conscience to any set of first principles which may suit them. It is our part as instructors to interpret the facts of conscience, not to seek for them an ultimate explanation.