We must assume that sexual intercourse was irregular and haphazard up to the dawn of history. Every woman—within the limits of her own tribe, probably—belonged to every man. Whether this assumption is universally applicable or not, must remain doubtful; later ethnologists, more particularly von Westermarck, deny it because it does not apply to every savage tribe of the present day. Herodotus tells us that promiscuity existed in historical times in countries as far removed from each other as Ethiopia and the borders of the Caspian Sea. There can be no reasonable doubt that sexual intercourse took the form of group-marriage, the exchange or lending of wives, and other similar arrangements.
The relationship between mother and child having been established by Nature herself, the first human family congregated round the mother, acknowledging her as its natural chief. This continued even after the causal connection between generation and birth had ceased to be a mystery.