I. Definition. This is necessary because it has sometimes been confounded with the question: What is the ground of obligation?[38] We must distinguish between the "ground of right" and the "ground of obligation." The point before us is not why we are under obligation to do a right act, but why the act is right. Manifestly the rightness of the proposed action is the ground of the obligation to do it; that is, the obligation is grounded on the right. The exact inquiry is--and must be, in order to reach the real and abiding moral foundations--on what is the right, whose perception obligates, grounded? A quest after the ground of the "obligation" simply, might satisfy those who reduce conscience to a mere instinct or sentiment, and the moral standard to a mere internal product of association, education or of biological organization. To them it might seem enough to give an explanation of the felt obligation. In such case they might plausibly, as they often do, affirm that the moral bond, being thus organically insured and fixed in the moral consciousness, must remain the same, no matter what theories, even though purely materialistic, may be formed of its genesis and nature. But so soon as the ethical reality is seen in its cosmic place and transcendental character we want an explanation not only of the ground of obligation to right conduct, but also of the ground of the right which evokes the sense of obligation. ==Various Theories.== II. Leading Theories. We must include, in this review, both the theories which offer only an explanation of the phenomenon of obligation and those that seek an elucidation of the principle of righteousness as objective moral law. In the long continued discussion of the subject these theories have been immensely varied and modified, but the differences thus noted divide all explanations into two classes, viz., those which make the moral stand in something subjective and those that find it objective. In the cursory rehearsal of them, here needed, we will present them in chronological order, irrespective of their belonging to one class or the other, noting, however, their relation to this distinction which divides them. Such historical glance will give an outline of the development of thought on the subject, and help us to reach and appreciate the true conclusion. ==Egyptian Teaching.==