The great majority of organisms live social lives, and so are united by the link of common interests. Of all the relations which determine the existence of the species, the chief are those which bind the individual to other individuals of the species. This is at once clear from the laws of sexual propagation. Moreover, the association of individuals is a great advantage in the struggle for existence. In the case of the higher animals this association becomes particularly important, because it is accompanied by an extensive division of labor. Then arises the antithesis of the personal egoism and the communal altruism; and in human societies the opposition of the two instincts is all the greater when reason recognizes that each has a right to satisfaction. Social habits become moral habits, and their laws are afterwards taught as sacred duties, and form the basis of the juridical order.
The morals of nations, so rich in psychological and sociological interest, are nothing more than social instincts, acquired by adaptation, and passed on from generation to generation by heredity. An attempt has been made to distinguish between the two kinds of habit by describing the instincts of animals as constant vital functions based on their physical organization, and the habits or morals of human beings as mental powers maintained by a spiritual tradition. This distinction has, however, been excluded by the modern physiological teaching that men's morals are, like all their other psychic functions, based physiologically on the organization of their brain. The habits of the individual man, which have been formed by adaptation to his personal conditions, become hereditary in his family; and these family usages can no more be sharply distinguished from the general morals of the community than these can be from the precepts of the Church and the laws of the state.
When a certain habit is regarded by all the members of a community as important, its cultivation favored and its breach punished, it is raised to the position of a duty. This is true even in the case of the herds of mammals (apes, gregarious carnivora, and ungulates) and the flocks of social birds (hens, geese, ducks). The laws which have been formed in these cases by the higher development of social instincts are particularly striking and equivalent to those of savage tribes when conspicuous individuals (old or strong males) have acquired a leadership of the troop, and successfully insure the observance of the proper habits or duties. Many of these organized bands are in some respects higher than the savages at the lowest stages who live in isolated families, or only form loose temporary associations of a few families. The great progress made by comparative psychology and ethnology, and historical and prehistorical research, in the second half of the nineteenth century, confirms us in the conviction that a long scale of intermediate stages joins the rudiments of law in the social primates and other mammals to the sense of law in the lower savage, and this again to that of the barbarian and the civilized human being—right up to the science of law in modern Europe.
Like civil laws, the commands of religion come originally from the morals of the savage, and eventually from the social instincts of the primates. The important province of mental life to which we give the vague name of religion was developed at an early stage among the prehistoric races from whom we all descend. When we study its origin from the point of view of empirical psychology and monistic evolution, we find that religion has arisen polyphyletically from different sources—ancestor worship, the desire of personal immortality, the craving for a causal explanation of phenomena, superstition of various kinds, the strengthening of the moral law by the authority of a divine law-giver, etc. According as the imagination of the savage or the barbarian followed one or other of these lines it raised up hundreds of religious forms. Only a few of them survived in the struggle for existence, and acquired (at least outwardly) dominion over the modern mind. But as independent and impartial science advances in our time, religion is purified of superstition and turns more and more to morality.
The obedience to the "divine commands" which religion demands of its followers is often transferred by human society to rules that have arisen from social customs of subordinate kinds. Thus we get the familiar confusion of manners and morals, of conventional outer deportment and real inner morality. The ideas of good and bad, morality and immorality, are subjected to arbitrary definitions. In this a great part is played by the moral pressure which is exercised by conventional ideas in the social body on the conduct and minds of its members. However clearly and rationally the individual thinks about the important questions of practical life, he has to yield to the tyranny of traditional and often quite irrational customs. As a matter of fact, both in life and in the nature of the case practical reason does take that precedence of pure reason which Kant claimed.
The tyranny of custom in practical life does not depend merely on the authority of social usage, but also on the power of selection. Just as natural selection insures the relative constancy of the specific form in the origin of the animal and plant species, so it has a powerful effect on the origin of morals and customs. An important factor in this is mimetic adaptation, or mimicry, the aping or imitating of certain forms or fashions by various classes of animals. This is unconscious in the case of many orders of insects, butterflies, beetles, hymenoptera, etc. When insects of a certain family come to resemble in their outer form and color and design those of another family, they obtain the protection or other advantages which these particular characters give in the struggle for life. Darwin, Wallace, Weismann, Fritz Müller, Bates, and others, have shown in numbers of instances how the origin of these deceptive resemblances can be traced to natural selection, and how important they are in the formation of the species. But many customs and usages in human life arise in just the same way, partly by conscious and partly by unconscious imitation. Of these the varying external forms which we call "fashions" have a most important influence in practical life. The phrase "fashion-ape," when used in a scientific sense, is not merely an expression of contempt, but has also a profound meaning; it correctly indicates the origin of fashions by imitation, and also the peculiar resemblance we find in this respect between man and his cousins, the apes. Sexual selection among the primates has a good deal to do with this.
The great importance which Darwin ascribes in his Descent of Man to the æsthetic selection of the respective sexes is equally true of man and of all the higher vertebrates that have a feeling of beauty, especially the amniotes (mammals, birds, and reptiles). The beautiful coloring and marking and ornamentation which distinguish the males from the females are due entirely to the careful individual selection of the former by the latter. Thus the various kinds of ornamental hair (beard, hair of head, etc.), the tint of the face, the peculiar form of the lips, nose, ears, etc., are to be explained, as we find them in man and the male ape; also the brilliant plumage of the humming-bird, the bird of paradise, pheasant, etc. I have dealt fully with these interesting facts in the eleventh chapter of the History of Creation, and must refer the reader thereto. I will only point out here how valuable the whole of this chapter of Darwinism is for the understanding of the foundation of species on the one hand and men's fashions and customs on the other. It is most closely connected with ethical problems.
The growth of fashion in civilized life is very important, not only for the development of the sense of beauty and for the sexual selection of the sexes, but also in connection with the origin of the feeling of shame and the finer psychological traits that relate to it. The lower savages have no more sense of shame than animals or children. They are quite naked, and accomplish the sexual act without the slightest trace of shame. The beginning of clothing which we find among the middle savages is not due to a sense of shame, but partly to low temperature (in the polar regions), partly to vanity and love of decoration (such as ornamenting the ears, lips, nose, and sex-organs by the insertion of shells, pieces of wood, flowers, stones, etc.). Afterwards the sense of shame sets in, and we have the covering of certain parts of the body with leaves, girdles, shirts, etc. In most nations the sexual parts are the first to be covered; though some attach importance to the veiling of the face. In many Oriental tribes (especially Mohammedan) it is still the first precept of female chastity to veil the face (the most characteristic part of the individual), while the rest of the body may remain naked. Generally speaking, the æsthetic and psychological relations of the sexes play the chief part in the higher development of morals. Morality is often taken to be synonymous with the law of sexual intercourse.
As the features of civilized life advance, the influence of reason increases, and so does the power of hereditary tradition and the moral ideas associated with it. The result is a severe conflict between the two. Reason seeks to judge everything by its own standard, to learn the causes of phenomena and direct practical life accordingly. On the other hand tradition, or "good morals," looks at everything from the point of view of our forefathers and other venerable laws and religious precepts. It is indifferent to the independent discoveries of reason and the real causes of things. It demands that the practical life of every individual be framed in accordance with the hereditary morality of the race or state. Thus we get the inevitable conflict between reason and tradition, or science and religion, which continues in our own day. Sometimes in the course of it a "new fashion" is substituted for some sacred tradition, a transitory custom that succeeds in imposing itself by its novelty or curiosity; and when this has contrived to win general acceptance, or has gained the support of Church or state to some extent, it is regarded in much the same light as the older morality.
The lowest races of the present time (for instance, the pithecoid pygmies, the Veddahs of Ceylon, the Akkas of Central Africa) are very little higher than their primate ancestors in mental development. This is also true of their habits of life and morals. As their ideas are for the most part concrete and sensual, their power of forming abstract concepts is very little developed; they have hardly any religious ideas to speak of. But with the middle savages we begin to find the craving to know the causes of things and the idea of spirits that are concealed behind the phenomena of sense. Dread of these leads to worship, fetichism, and animism, the beginning of religion. Even at this early stage of worship we find certain customs associated with the cult to which a symbolical or mysterious meaning is given. These ceremonies lead on in the higher races to the great religious festivities, which the Greeks called "mysteries." Sensual images of various kinds are mixed up in them with supersensual ideas and superstitions. The festivals, processions, dances, hymns, and sacrifices of all sorts that form part of the cult are more or less concerned with the mysterious, and are therefore considered "holy." They are often made the pretext of sensual gratifications, which end in gross immorality and orgies.