These modifications slowly and gradually contract the circle comprised by the common tie of marriage until only the single couple remains which prevails to-day.
In thus constructing backward the history of the family, Morgan, in harmony with the majority of his colleagues, arrives at a primeval condition, where unrestricted sexual intercourse existed within a tribe, so that every woman belonged to every man, and vice versa.
Much has been said about this primeval state of affairs since the eighteenth century, but only in general commonplaces. It is one of Bachofen's great merits to have taken the subject seriously and to have searched for traces of this state in historical and religious traditions. To-day we know that these traces, found by him, do not lead back to a stage of unlimited sexual intercourse, but to a much later form, the group marriage. The primeval stage, if it really ever existed, belongs to so remote a period, that we can hardly expect to find direct proofs of its former existence among these social fossils, backward savages. Bachofen's merit consists in having brought this question to the fore.7
It has lately become a fashion to deny the existence of this early stage of human sex life, in order to spare us this "shame." Apart from the absence of all direct proof, the example of the rest of animal life is invoked. From the latter, Letourneau (Evolution du mariage et de la famille, 1888) quoted numerous facts, alleged to prove that among animals also an absolutely unlimited sexual intercourse belongs to a lower stage. But I can only conclude from all these facts that they prove absolutely nothing for man and the primeval conditions of his life. The mating of vertebrates for a lengthy term is sufficiently explained by physiological causes, e. g., among birds by the helplessness of the female during brooding time. Examples of faithful monogamy among birds do not furnish any proofs for men, for we are not descended from birds.