Natural selection would again certainly come into play in favour of such groups, thus curtailing the monstrous prerogatives of the old-world fathers, by dint of numbers alone. The superiority which would ensue with each generation, would speedily ensure the triumph of that assembly which could definitely accept the presence of the outside suitor. He would come as a multiple unit of strength, a willing ally who would otherwise have been an active enemy--the generator of the productive power to females who would either have remained as sterile residents, or seceded to hostile hordes as breeders of new foes. Thus, then, we may at length perceive how a custom even so deeply ingrained in nascent man as paternal incest, may finally have become extinct as a custom. In the action of such circumstances we can accept the idea of its ultimate decay and death. By the numerical preponderance of the individuals within a group interested in its disappearance, was alone such a result feasible. This necessary condition we here find fulfilled. In opposition to the father we now see arrayed not only the wife-mother jealous of her mate, not only the daughter inclined instinctively to youth and the unknown, but, most important of all, the son, now egged on by most powerful personal feelings and interests. And for these latter ones, as we have seen, time itself would fight; to youth each hour and day is a gain in strength, to old age each moment means a loss of power. With the decay of the custom we see that the way lies clear to progress in group formation. Sooner or later the presence of the offspring of the outside suitors in the formerly purely consanguine circle will be recognised, their recognition as cousins to the younger resident members will be made, and the old type of horde by a process of cleavage divides itself into two intermarriageable clans, (phratries?), and the savage tribe is created.[6]