In the courtship of almost all animal species the male plays the most active part, and has generally to fight with other males for the possession of the female. The same was no doubt the case with our early human ancestors, and this mode of courtship survives even now among some of the lower races. Much more commonly, however, courtship means on the part of the man a prolonged making of love; and the woman is far from being completely passive. We have seen how savage men and women in various ways endeavour to make themselves attractive to the opposite sex:—by ornamenting, mutilating, painting, and tattooing themselves. That these practices essentially subserve this end appears chiefly from the fact that the time selected for them is the age of puberty. It seems also probable that clothing, at least in a great many cases, was originally adopted for a similar reason, and that the feeling of shame, far from being the original cause of man’s covering his nakedness, is, on the contrary, a result of this custom.

Whilst the men are generally the courters, the women may in many, perhaps most, cases accept or refuse their proposals at pleasure. Though a daughter among the lower races is regarded as an object of property, and is in many instances betrothed in her earliest youth, women are not, as a rule, married without having any voice of their own in the matter. Among existing savages their liberty of selection is very considerable, and under more primitive conditions—when every grown-up individual earned his or her own living, when there was, strictly speaking, no labour, and when a daughter consequently was neither a slave nor an object of trade—woman was doubtless even more free in that respect than she is now among most of the lower races. At a latter stage the case was different. Among peoples who have reached a relatively high degree of civilization the father’s power, in connection with a more fully developed system of ancestor-worship, has invariably become more extensive, more absolute. Not only the full-grown daughter, but the full-grown son, who among savages enjoys perfect independence, stands so much in awe of the father that, among many of these peoples, no marriage is concluded without his consent. We have given some account of this strengthened paternal authority among various nations; we have found that it has formed only a transitional stage in the history of human institutions; and we have indicated the stages of its gradual decline.

The important subject of sexual selection has necessarily claimed a good deal of attention. In an introductory chapter we pointed out the contradiction between Mr. Darwin’s theories of natural and sexual selection, and endeavoured to show that the sexual selection of the lower animals is entirely subordinate to the great law of the survival of the fittest. From the way in which the sexual colours, odours, and sounds of animals are distributed among different species, we drew the conclusion that, though they are always to a certain extent hurtful to the species, they are upon the whole advantageous, inasmuch as they make it easier for the sexes to find each other; whereas if we accept Mr. Darwin’s theory, we are compelled to suppose that the inexplicable æsthetic sense on which his hypothesis is founded, has been developed in the way most dangerous to the species. We also found that there are facts incompatible with Mr. Darwin’s explanation of the connection between love and beauty in mankind, and of the origin of the different human races. There is an ideal of beauty common to the whole human race; but this ideal is a mere abstraction, as general similarities in taste are accompanied by specific differences. Men and women find beauty in the full development of the visible characteristics belonging to the human organism in general; of those peculiar to the sex; of those peculiar to the race. As a certain kind of constitution is best suited for certain conditions of life, and the racial type is on the whole that which best harmonizes with the external relations in which the respective peoples live, we may infer that the full development of racial characters indicates health, that a deviation from them indicates disease. Physical beauty is therefore in every respect the outward manifestation of physical perfection, and the development of the instinct which prefers beauty to ugliness, healthiness to disease, is evidently within the power of natural selection. According to Mr. Darwin, racial differences are due to the different standards of beauty, whereas, according to the theory indicated in this book, the different standards of beauty are due to racial differences. We have seen that the racial peculiarities stand in some connection with the external circumstances in which the various races live. But, as we do not know that acquired characters are transmitted from parent to offspring, it is exceedingly doubtful whether the differences are the inherited effects of conditions of life to which previous generations have been subject. It seems most probable that they are due to natural selection, which has preserved and intensified such congenital variations as were most in accordance with the conditions under which the various races lived.

Under the head of the ‘Law of Similarity’ we dealt with the powerful instinct which, as a rule, keeps animals from pairing with individuals belonging to another species, and found the origin of this aversion in the infertility of first crosses and hybrids. No such instinct can be said to keep the various human races apart from one another; and it is not known that the diversities even between the races which least resemble each other are not so great but that, under favourable conditions, a mixed race may be produced. Closely akin to the horror of bestiality is the horror of incest, which, almost without exception, is a characteristic of the races of men, though the degrees within which intercourse is forbidden vary in an extraordinary degree. It is nearly universally abominated between parents and children, generally between brothers and sisters, often between cousins, and, among a great many peoples uninfluenced by modern civilization, between all the members of the tribe or clan. We criticized the theories set forth by various writers as to the origin of such prohibitions. To each of these theories there are special objections; and all of them presuppose that men avoid incestuous marriages only because they are taught to do so. As a matter of fact, the home is kept pure from incestuous intercourse neither by laws, nor by customs, nor by education, but by an instinct which under normal circumstances makes sexual love between the nearest kin a psychical impossibility. Of course there is no innate aversion to marriage with near relations; but there is an innate aversion to marriage between persons living very closely together from early youth, and, as such persons are in most cases related, this feeling displays itself chiefly as a horror of intercourse between near kin. The existence of an innate aversion of this kind is proved, not only by common experience, but by an abundance of ethnographical facts which show that it is not in the first place by degrees of consanguinity, but by close living together, that prohibitory laws against intermarriage are determined. Thus many peoples have a rule of local exogamy, which is quite independent of kinship. The extent to which, among various nations, relatives are not allowed to intermarry, is obviously nearly connected with their close living together. There is so strong a coincidence (as statistical data prove) between exogamy and the “classificatory system of relationship”—which system springs, to a great extent, from the close living together of considerable numbers of kinsfolk—that they must, in fact, be regarded as two sides of one institution. Prohibitions of incest are very often more or less one-sided, applying more extensively either to the kinsfolk on the father’s side or to those on the mother’s, according as descent is reckoned through men or women; and we have seen that the line of descent is intimately connected with local relationships. In a large number of cases, however, prohibitions of intermarriage are only indirectly influenced by the close living together. Aversion to the intermarriage of persons who live in intimate connection with each other has provoked prohibitions of the intermarriage of relations; and, as kinship is traced by means of a system of names, the name comes to be considered identical with relationship. Generally speaking, the feeling that two persons are intimately connected in some way or other may, through an association of ideas, give rise to the notion that intercourse between them is incestuous. There are exceptions to the rule that close living together inspires an aversion to intermarriage. But most of the recorded instances of intermarriage of brother and sister refer to royal families, and are brought about simply by pride of birth. Incestuous unions may also take place on account of extreme isolation, and certain instances of such connection are evidently the results of vitiated instincts. Marriage between a half-brother and a half-sister, however, is not necessarily contrary to the principle here laid down, as polygyny breaks up each family into as many sub-families as there are wives who have children. The question arose:—Why is a feeling of disgust associated with the idea of marriage between persons who have lived in a long-continued, intimate relationship from a period of life at which the action of desire is naturally out of the question? We found an answer in the evil effects resulting from consanguineous marriages. It seems to be necessary for the welfare of the species that the sexual elements which unite shall be somewhat different from, as it is necessary that they shall be in some way similar to, one another. The injurious results of self-fertilization among plants and of close interbreeding among animals appear to prove the existence of such a law, and it is impossible to believe that it does not apply to man also. We stated several facts pointing in this direction, and found reason to believe that consanguineous marriages are much more injurious in savage regions, where the struggle for existence is often very severe, than they have proved to be in civilized society. We also observed that no evidence which can stand the test of scientific investigation has hitherto been adduced against the view that consanguineous marriages, in some way or other, are more or less detrimental to the species. Through natural selection an instinct must have been developed, powerful enough, as a rule, to prevent injurious unions. This instinct displays itself simply as an aversion on the part of individuals to union with others with whom they have lived, but as these are for the most part blood-relations, the result is the survival of the fittest.

We proceeded to consider sexual selection as influenced by affection, sympathy, and calculation. We found that love has only slowly become the refined feeling it is in the minds of cultivated persons in modern times, although conjugal affection is far from being unknown, even among very rude savages. The endogamous rules which prevent different races, nations, or tribes, hereditary castes, classes, and adherents of different religions from intermarrying are due to want of sympathy, and have gradually lost their importance according as altruism and religious toleration have increased, and civilization has diminished the barriers which separate different nations and the various classes of society.

As regards the mode of contracting marriage, we inferred—from the universality of the horror of incest, and from the difficulty a savage man has in procuring a wife in a friendly manner without making up for the loss he inflicts on her father—that marriage by capture must have been very common at that stage of social development when family ties had become stronger, and man lived in small groups of nearly related persons, but when the idea of barter had scarcely presented itself to his mind. We saw that marriage by capture was succeeded by marriage by purchase, as barter in general has followed upon robbery. Again, at a later stage, some feeling of shame was attached to the idea of selling a daughter, and marriage by purchase was abandoned. Its gradual disappearance took place in two different ways. On the one hand, the purchase became a symbol, appearing as a sham sale in the marriage ceremonies or as an exchange of presents; on the other hand, the purchase-sum was transformed into the morning gift and the dotal portion, a part—afterwards the whole—being given to the bride either directly by the bridegroom or by her father. These transformations of marriage by purchase have taken place, not only in the history of the great civilized nations, but among several peoples who are still in a savage or semi-civilized state. As a rule, however, the marriage portion plays no important part in savage life, being chiefly due to a feeling of respect and sympathy for the weaker sex, which, on the whole, is characteristic of a higher civilization. Very often it is intended to be a settlement for the wife in case the marriage be dissolved through the husband’s death or otherwise, although it may have the meaning of a return gift, or it may imply that the wife as well as the husband is expected to contribute to the expenses of the joint household.

Having noted the growth of marriage ceremonies and religious rites, we passed to the forms of human marriage. Polygyny was permitted by most of the ancient peoples within the historic period, and is at present permitted by several civilized nations and by the majority of savage tribes. Yet, among not a few savage and barbarous races it is almost unknown, or even prohibited; and almost everywhere it is confined to the smaller part of the people, the vast majority being monogamous. Moreover, where polygyny occurs, it is modified, as a rule, in two ways that tend towards monogamy: through the higher position granted to one of the wives, generally the first married, and through the favour constantly shown by the husband to the wife he likes best. Among certain peoples polyandry occurs, and, like polygyny, is modified in a monogamous direction, the first husband usually being the chief husband. Among the causes by which the forms of marriage are influenced, the numerical proportion between the sexes plays an important part. In some countries there are more men than women, in others more women than men. This disproportion is due to various causes, such as female infanticide, war, and disparity in the number of the sexes at birth. There are facts which seem to show that in rough mountainous countries more boys are born than girls, and that consanguineous marriages produce a considerable excess of male births. If this be so, it can hardly be a mere coincidence that polyandry occurs chiefly among mountaineers and peoples who are endogamous in a very high degree. As for polygyny, there are several reasons why a man may desire to possess more than one wife. Among many peoples the husband has to live apart from his wife during her pregnancy, and as long as she suckles her child. Female youth and beauty have for men a powerful attraction, and among peoples at the lower stages of civilization women generally become old much sooner than in more advanced communities. The liking of men for variety is also a potent factor; and to have many wives is to have many labourers. The barrenness of a wife is another very common reason for the choice of a new partner, as desire for offspring, for various reasons, is universal in mankind. In a savage and barbarous state a man’s power and wealth are proportionate to the number of his offspring. Nevertheless, however desirable polygyny may be from the man’s point of view, it is prohibited among many peoples, and among most of the others it is exceptional. Where the amount of female labour is limited, and no accumulated property exists, it may be very difficult for a man to keep a plurality of wives. Again, where female labour is of considerable value, the necessity of paying the purchase-sum for a wife is a hindrance to polygyny, which can be overcome only by the wealthier men. Polygyny implies a violation of the feelings of women; hence, where due respect is paid to these, monogamy is considered the only proper form of marriage. The refined passion of love, which depends not only on external attractions, but on sympathy arising from mental qualities, forms a tie between husband and wife which lasts for life; and the true monogamous instinct, the absorbing passion for one, is a powerful obstacle to polygynous habits. It is certain that polygyny has been less prevalent at the lowest stages of civilization—where wars do not seriously disturb the proportion of the sexes; where life is chiefly supported by hunting, and female labour is consequently of slight value; where there is no accumulation of wealth and no distinction of class—than it is at somewhat higher stages; and it seems probable that monogamy prevailed almost exclusively among our earliest human ancestors. But, though civilization up to a certain point is favourable to polygyny, its higher forms invariably and necessarily lead to monogamy. We have noted that polygyny has, in many ways, become less desirable for the civilized man than it was for his barbarian and savage ancestors, and that other causes have co-operated to produce the same result. Again, polyandry, being due to an excess of men and presupposing an abnormally feeble disposition to jealousy, must at all times have been exceptional; there is no solid evidence for the theory that in early times it was the rule. On the contrary, this form of marriage seems to require a certain degree of civilization. It was probably, in most cases, an expression of fraternal benevolence on the part of the eldest brother, and, if additional wives were afterwards acquired, it led to group marriages of the Toda type.

As a general rule, human marriage is not necessarily contracted for life, and among most uncivilized and many advanced peoples, a man may divorce his wife whenever he likes. Nevertheless, divorce is an exception among a great many races, even among races of the lowest type; and numerous nations consider, or have considered, marriage a union which must not be dissolved by the husband, except for certain reasons stipulated by custom or law. We also noted instances in which the wife may separate from her husband. The causes by which the duration of human marriage is influenced are, on the whole, but not exactly the same as those which determine the form of marriage; and, though monogamy frequently coexists with great stability of marriage, this is scarcely the case in the rudest condition of man. Marriage, generally speaking, has become more durable in proportion as the human race has advanced.

Marriage has thus been subject to evolution in various ways, though the course of evolution has not been always the same. The dominant tendency of this process at its later stages has been the extension of the wife’s rights. A wife is no longer the husband’s property; and, according to modern ideas, marriage is, or should be, a contract on the footing of perfect equality between the sexes. The history of human marriage is the history of a relation in which women have been gradually triumphing over the passions, the prejudices, and the selfish interests of men.