There is one thing which all reasoning about morality assumes and must assume; and that is morality itself. The moral concept--whether described as worth or as duty or as goodness--cannot be distilled out of any knowledge about the laws of existence or of occurrence. Nor will speculation about the real conditions of experience yield it, unless adequate recognition be first of all given to the fact that the experience which is the subject-matter of philosophy is not merely a sensuous and thinking, but also a moral, experience. The approval of the good, the disapproval of the evil, and the preference of the better: these would seem to be basal facts for an adequate philosophical theory: and they imply the striving for a best--however imperfect the apprehension of that best may always remain. Only when these facts--the characteristic facts of moral experience--are recognised as constituents of the experience which is our subject-matter, are we in a position profitably to enquire what is good and what evil, and how the best is to be conceived. The recognition of these facts would only be a beginning; but it would be a beginning which would avoid the cardinal error fallen into not only by the leading exponents of evolutionist morality, but also to be found in much of the ethical work of idealist metaphysicians. It seems to have been assumed that moral principles can be reached by the application of scientific generalisations or of the results of a metaphysical analysis which has started by overlooking the facts of the moral consciousness. Even as a metaphysic this procedure is inadequate; and the interpretations of reality to which it has led have erred by over-intellectuality. The systems of naturalism and of idealism, whose ethical consequences have been passed in review, have one feature in common; and it is a feature which from of old has been regarded as a mark of genuine philosophy. They both seek the One in the many; but they seek it on different roads. For the naturalist the most comprehensive description of things may be the conception of mass-points in motion; or it may be some more recondite conception to which physical analysis points. In either case the unity reached will be mechanical. For the idealist, on the other hand, reason may be said to be the central principle of things: the unity of reality is a rational unity. I have contended in these lectures that neither the mechanical unity of the naturalists nor the rational unity of the idealists has succeeded in comprehending within its unifying principle the essential nature of morality with its deep-going dualism of good and evil. But while I have maintained that even the conception of reality as the reproduction of itself by an eternal self-consciousness is an inadequate conception, it is still possible to hold that reality is a connected whole, and that its true principle of unity is an ethical principle.