Indeed, I leave it out of this book altogether. The moralist must, I think, assume that man has natural impulses and is a rational creature. Those who are interested in the problem above mentioned, may turn to my Introduction to Philosophy, chapter xi, Sec 46, where the matter is discussed, and references (in the corresponding note) are given.
Chapter XVI.—The matter of this chapter appears, clear enough, but it may be well to give a few references touching the two conceptions of the functions of Reason.
Men of quite varying views have inclined to the doctrine which appeals to me. I think it is to be gotten out of Hegel. Green, who is much influenced by him, takes, as the rational end of conduct, a "satisfaction on the whole," which implies a harmonization and unification of the desires (see, in this book, Chapter XXVI, Sec 122). Spencer, in his Study of Sociology, defines the rational as the consistent. Stephen, in his Science of Ethics, chapter ii, Sec 3, says: "Reason, in short, whatever its nature, is the faculty which enables us to act with a view to the distant and the future." He claims that rationality tends to bring about a certain unity or harmony. Hobhouse, Morals in Evolution, (pp. 572-581), says that reason harmonizes the impulses.
The champions of the opposite view are the intuitionists proper—such men as Kant, Reid, Price, even Sidgwick. To judge of their doctrine—they were great men, be it remembered, and worthy of all respect—I suggest that the reader wait until he has read the chapter on Intuitionism in this volume, Chapter XXIII.
5. CHAPTERS XVII TO XIX.—What is said in Chapter XVII seems too obviously true to need comment. Indeed, it may be questioned whether the chapter is not full of platitudes. But even platitudes are overlooked by some; and there is some merit in arranging them systematically. Besides, they may serve as a spring-board.
As to Chapter XVIII, I suggest reading chapter vii, of Westermarck's book on The Origin and Development of the Moral Ideas. It is entitled Customs and Laws as Expressions of Moral Ideas.
For Chapter XIX, one may read Hobhouse, Morals in Evolution, Part I, chapter vi, where he shows how the mere "group morality" gradually gives place to a wider morality in which the concept of humanity plays a part. In the same work, Part II, chapters i and ii, the author treats of religious or sub-religious ideas as affecting conduct. Compare Westermarck, op. cit., chapter xl. See, also, The Ancient City, by Fustel de Coulanges.
6. CHAPTERS XX TO XXII.—What is said in Chapter XX may be well reinforced by turning to Hobhouse (op. cit.), Part I, chapter iii, where he traces the gradual evolution of rational morality in the field of justice. See, also, Westermarck, (op. cit.) chapters ix and x, i. e., "The Will as the Subject of Moral Judgment and the Influence of External Events," and "Agents under Intellectual Disability." In the last chapter referred to, animals, drunkards, idiots, the insane, etc., come on the stage. The chapter is full of curious information.
In Chapter XXI (Sec 86), I have spoken of the hesitating utterances of moralists touching any duties we may owe to the brutes. I suggest that before anyone dogmatize in detail on this subject he read with some care such a comprehensive work as Miss Washburn's The Animal Mind. The book is admirable. Chapters x and xliv of Westermarck's work are instructive and entertaining on this subject. Hegel disposes of the animals rather summarily. See his Philosophy of Right, Sec 47. Sidgwick, The Methods of Ethics, Book III, chapter iv, 2, is well worth consulting. See in my own volume, Chapter XXX, Sec 141.
For Chapter XXII, I give no references. I appeal only to the common sense of my reader.