The unilateral principle is thus instrumental in securing for the clan the same condition of sexually undisturbed co-operation as is secured for the family by the prohibition of incest.
Unilateral descent is also intimately bound up with the nature of filiation, that is, with the handing over of status, power, office and possessions, from one generation to the other. Order and simplicity in the rules of filiation are of the greatest importance for social cohesion. Indeed, we find that most political quarrels and tribal dissensions are due, apart from sex, to questions of inheritance and succession,—from lowest savagery right up to modern civilization. Rivalries during lifetime, fights and rifts after the death of a man, especially if he be powerful, are of universal occurrence. For, as we know, mother-right and father-right are never absolute and the rules are always elastic and sometimes ambiguous. The generalization may, therefore, be laid down that the simpler and stricter the laws of filiation, the more stringently enforced either mother-right or father-right at the expense of the other, the greater will be the order and cohesion in a community, the smoother will be the transmission of authority, tradition and wealth from one generation to the other.
In the earler stages, the infant is mainly passive—as when it forms the first bonds by accepting the parental cares; as when it is weaned from the mother ; taught to name its parents ; to accept a substitute mother and father and to extend to them the parental appellations. Later on when the baby assumes the status of a child, often by donning the first dress, when he begins to follow the parents and takes some part in their pursuits, his interest in new associations and in the formation of new bonds becomes more active too.
Then there comes, in some tribes at least, again a stage of abrupt, passively received training. The rites of tribal initiation as a rule, entail a dramatic break with the old life and the creation of new bonds. The novice is made to forget his associa tions with the family, especially with its female members, above all with the mother. In the course of the moral and mythological training which he receives, he is taught in a systematic way what kinship means, he is instructed in the principles of unilateral descent, the rules of exogamy, the duties and responsibilities towards his kindred and relatives. In other tribes, where there are no initiation rites, the same moral and legal education is given gradually, spread over a longer period—but it always has to be received, and it is always given with reference to kinship.
The boy and girl now enter the active life of the tribe. Often the individual has to change his residence, the girl on marrying into another village, the boy on assuming his full unilateral kin ship status. In matriarchal and patrilocal communities, for in stance, he leaves his father's place and joins his mother's brother. With this a new recrystallization of kinship bonds takes place— always, however, on the same principle : with the old pattern carried over, but adjusted to the individual's new status and to his new conditions of life.
Marriage opens a new phase and constitutes another transition (see s.v.). Here a new set of• relatives is acquired, besides the individual mate, and the terminology is enriched by another set of expressions, as a rule some taken over from the old vocabulary of kinship, and some new ones added. Incidentally a new house hold is founded, with which the whole kinship story starts afresh.
Later on, with old age, with the marriage of children and the arrival of grandchildren, the kinship horizon changes once more, as a rule by the growth and multiplication of the younger gen eration, lineal and collateral, and by their gradual taking of duties, responsibilities and privileges out of Ego's hands.