“Thus, the evolution of the family in prehistoric times consisted in the continual narrowing of the circle--originally embracing the whole tribe--within which marital community between the two sexes prevailed. By the successive exclusion, first of closer, then of ever remoter relatives, and finally even of those merely related by marriage, every kind of group marriage was ultimately rendered practically impossible; and in the end there remained only the one, for the moment still loosely united, couple, the molecule, with the dissolution of which marriage itself completely ceases. This fact alone shows how little individual sex love, in the modern sense of the word, had to do with the origin of monogamy.”
