tive element in human nature is responsible for the appearance of morality. Besides this stable instinctive factor, modifiable instinctive elements as well as habits, sentiments, reflective thinking, and the tremendous suggestive force of custom and tradition unite to determine values for each of us, and so to give us our moral conceptions. The difficult thing to do is to detach the instinctive factor, and to distinguish the stable element within it from the other phases of mental life which are more flexible and hence more indeterminate.
While the other two chief accounts of moral evolution have recognized the significance of the instincts more fully than Westermarck, they have not discriminated this stable element in them. Sutherland's[1] account too vaguely regards morals as instinctive, and while it doubtless correctly indicates the principal line of moral evolution in its descent from the parental instinct, it indiscriminatingly brings all moral impulses and values under the "moral instinct" without much further analysis.
Professor Hobhouse, an animal psychologist as well as a sociologist and philosopher of distinction, recognizes that human loves and hates, joys and sorrows, pride, wrath, gentleness, boldness and timidity are permanent qualities that run through humanity and vary only in degree. But though they are of the nature of instincts, they have become so highly plastic and modifiable that until the individual has had experience they are "a mere blank form upon which nothing is yet written."[2] Ethical progress is to be found, "not in the development of new instincts or impulses of mankind or in the disappearance of instincts that are old and bad, but rather in the rationalization of the moral code, which, as society advances, becomes more clearly thought out and more consistently and comprehensively applied."[3] In carrying out this program a convincing and inspiring account of ethical evolution is furnished, which traces the development of conceptions as embodied in custom and law, and influenced by social institutions and religious thought, without any further inquiry concerning the relationship between
