The opinion, first expressed by L. H. Morgan, that the classificatory relationship system is evidence of the existence of group marriage (not merely in the form of pirauru existing at the side of monogamy), is contradicted by the etymological meaning of the terms used by primitive people, which are generally translated by "father," "mother," "grandfather," "brother," "sister," "child," etc. These collective names show nowhere an allusion to procreation, but only to age differences: father and mother are the "elder," the "big ones," the "grown-ups"; the children are the "little ones," the "young ones"; brothers and sisters are the "comrades." We often find that among the Australian negroes and the South Sea islanders no distinction is made between father and mother. All persons of an older generation of a horde or a totem (or of a phratry respectively) are simply the "elder," the "big ones." If a native wishes to indicate more clearly the sex of a person of an older class, he must add the word "man" or "woman" (or the adjective "male" or "female"). It often happens that grandparents and grandchildren use the same form of address, which in no way refers to descent (Cunow). Other facts point to the same conclusion. Where the pirauru exists in Australia, the same form of address is used for persons standing in pirauru relationship to the speaker as for members of the same age class who have no such relationship. This could not be so if the appellation had originated from common sexual relationship. Cunow rightly concludes: "Sexual communities can be proved to exist here and there among primitive peoples, but the nomenclature of the classificatory relationships has not grown out of such group relationships. These so-called group marriages are rather adventitious growths, playing only a secondary rôle in the history of the family."

Buschan (1912, p. 254) looks upon the pre-marital sexual freedom of girls among many primitive peoples (most probably among the majority of them) as a relic of communal marriage from earlier times. He assumes that the girls had promiscuous relationships with the other sex. This, however, is not the case. As a rule, couples meet together for a time, and only rarely does a person have relationship with several persons at the same time. The conditions are essentially the same as in Europe, except that amongst "savages" a love affair going as far as intercourse is not considered immoral. The assumption of many authors that man is polygynous is far from being proved, at least not in the sense that the majority of men are inclined to have relationship with several women at the same time. It cannot, however, be disputed that after some time the relationship between two people tends to lose its attraction, often causing a breaking of the marriage vow.

There is a custom among many peoples that a man's widow falls to his younger brother (or cousin)—the levirate. According to another custom, a man has the right to marry the sisters of his wife. Both these customs have been explained as being relics of a form of marriage in which brothers married several sisters or sisters married brothers at the same time (Frazer, II., p. 144). But it seems much more likely that we have here before us merely a case of property rights.

Even if constancy in marriage is not the rule, especially among primitive people, yet we must still regard the permanent living together of one man and one woman as a state that has always prevailed amongst human beings (Westermarck). Many of the speculations, at first sight so learned, about the apparently intricate paths in the development of marriage, remain merely speculations which cannot stand the test of modern ethnological research. Heinrich Schurtz (p. 175) makes the pertinent remark that nothing excited the hostile camps of the sociological idealists and naturalists more than the dispute about promiscuity in primitive times. While the one party painted with zest the indiscriminate and irregular sex relationship of primitive races, claiming it as an established original stage in human development, the adherents of idealism rose in indignation against a theory that places primitive man far below the level of the higher animals, and that leaves the riddle unsolved how such a chaos could lead to the idea of sexual purity and a spiritualisation of the sexual impulse. In this battle for and against promiscuity even facts were unfortunately too often not respected, attempts being made to disregard them at any cost. This cannot be good for the ultimate victory of truth. Facts should not be passed over, but should be taken into full consideration. In this conflict of opinions the institution of pirauru especially has fared particularly badly. Some anthropologists wanted to do away with it altogether at any price (for instance, Josef Müller); others drew conclusions from it that are utterly unjustified. But even if this were not so, even if the pirauru could be used as a proof of previous sexual promiscuity, it still does not follow that it was a general custom in man, for the majority of the peoples show no trace of it.

First of all, it must be noticed that even the pirauru possesses various restrictions upon marriage with persons outside certain groups, which alone exclude unrestrained promiscuity. Furthermore, individual marriage, the binding force of which is undoubtedly even stronger and closer, is well known to exist beside it. There is a good deal of probability for the assumption of Schurtz that marriage regulations establishing the right of several men to one wife may first have arisen from mere friendly acts, or the original sexual licentiousness may have developed occasionally under specially favourable circumstances into the institution of pirauru, while at other places such a systematic development did not take place. It is easily to be understood that lower civilisations will show a looser standard of the marriage bond than those where many interests of a rich cultural development require the strengthening of this bond. Sexual needs may also have brought about the origin of the pirauru institutions. Thus there exist in Australia tribes among which the loan of wives was customary owing to the scarcity of women. There is only one step from this state of affairs to the pirauru. Among many tribes complicated marriage restrictions make a "legitimate" marriage very difficult, and this may easily lead to other sex relationships taking the place of marriage.

It is a mistake to assume hastily that customs among primitive people that appear strange to us must therefore be ancient and be relics of a primitive state. Every primitive race has a long history behind it, and it is not likely that it has remained static all the time. Primitive people are not stationary in development; there is much change among them in the course of generations. This applies also to customs and habits which seem absolutely stable. External conditions may produce new developments, or result in foreign influences. Not everything, therefore, that is peculiar to uncivilised races of the present day must be looked upon as primitive.

Polyandry deserves our special consideration. As a recognised social institution it has so far been definitely established only among the Indian peoples and castes, as well as in Tibet, on the borders of Northern India. In exceptional cases polyandry occurs among the Eskimos and the Asiatic Polar races. The older accounts of polyandry occurring in Australia are not confirmed by the new ethnographical literature. The reports about polyandry among the American Indians are also incorrect. John Roscoe (1907, pp. 99 et seq.) has proved its existence among the Bahima and Baziba tribes of Central Africa, though here polyandry is not the rule, but is only practised occasionally. If a man is poor, if he cannot get together the number of cows required for the bride price, or if he is unable to support a wife, he can combine with one or several of his brothers and take a wife in common with them. It is easy to get the women for this purpose. Furthermore, among these tribes the housewife may be claimed by a guest, while exchange of wives also occurs.

In India polyandry is prevalent among the peoples of the Himalayan mountains and among some Southern Indian tribes. Some cases of this curious form of marriage are already mentioned in the ancient Indian literature. It may be assumed, therefore, that it was more prevalent formerly than at present. This institution was certainly never very general nor of great importance in the life of the people of India. At the present time it is restricted to a number of comparatively small tribes and castes. Two forms of polyandry can be distinguished among them, namely, the fraternal form, where several brothers or cousins have one wife in common, and the matriarchal form, where a woman has several husbands, not necessarily related to each other.

In Northern India polyandry is general among the Tibetans and Bhotias of the Himalayan border districts. Here, when the oldest of several brothers takes a wife, she has the right—but not the duty—to have sexual relationship with the other brothers living in the same household. If a younger brother also marries, the other still younger brothers have the choice in which household they wish to live. The surplus women become nuns. This system is said to be due to the poverty of the country. The Himalayan peoples, being intent on preventing the increase of the population and a further reduction of the means of existence, consign many women to celibacy and childlessness. Yet at the same time they make it possible, by this system, for the socially privileged man to satisfy his sexual needs. The children of polyandrous marriages belong, as a rule, legally to the oldest brother. But it also occurs that each brother in turn, according to his age, has a child assigned to him regardless of whether the brother concerned was on the spot at the time of the child's conception. Sometimes the mother has the right to name the father of each of her children.

Fraternal polyandry also exists in Cashmir and among certain Sudra castes of the Punjab mountains. In the Punjab, however, the Rajputs and other castes of that neighbourhood are also influenced by polyandry. The ceremonies which take place at marriage in the Punjab bear traces of "marriage by capture." The dwellings of the polyandrous castes of this district consist of two rooms, one for the woman and one for the group of brothers. In Tibet, as also among the polyandrous Southern Indians, they have, however, mostly one room. The surplus women in the Punjab become objects of commerce. In the native State of Bashar, for instance, an active export trade is carried on with the surplus women, for whom sums up to 500 rupees are given.