(_a_) Several further considerations may be offered to account for the growth of what we call humanity, (i) The long non-age of human children is favourable to the attachments of family life, and such attachments may under certain conditions be capable of extension beyond the family; but I cannot trace the whole flood of altruistic regard to the sole source of maternal or parental love. (ii) Friendliness and the disposition to mutual aid are so useful to a hunting-pack that is not merely seasonal but permanent (as I take ours to have been), both to individuals and to the pack as a whole, within certain limits (as that the wounded, sick, or aged must not amount to an encumbrance), that we may suppose natural selection to have favoured the growth of effective sympathy, not merely in mutual defence, but so far as it is actually found at present in backward tribes. It nowhere seems to be excessive; and its manifestation in some civilised races seems to depend not upon a positive increase of benevolence in the generality, but (iii) upon the breaking down here and there of conditions that elsewhere oppose and inhibit it. Thus the generosity, mercy and magnanimity that constitute the chivalrous ideal, depend (I believe) upon the attainment by a class of such undisputed superiority that there is no occasion for jealousy or rivalry in relation to other classes; for should the superiority be disputed, these virtues quickly disappear. Similarly, what have been called the “slavish virtues” of charity, humility, long-suffering may arise amongst those who are free from rivalry, because they have no hope of aggrandisement in wealth or honour, and who have indeed suffered long. With the interfusion of classes, their virtues interfuse; for they have a common root, and are active, provided that circumstances do not inhibit them.
(iv) But since in individuals our complex nature varies in all directions, and amongst the rest in the direction of benevolence; and since any organ or quality that varies is apt to continue to do so, and may go on varying even beyond the limits of biological utility; why in human life may not this happen with benevolence (or with any other passion or virtue); so that in some men it expands with wonderful richness and beauty even to the sacrifice of themselves—nay, by excessive clemency or generosity, even to the injury of the tribe or of the race?