DESCENT

the system of acknowledged social parentage, which varies from society to society, whereby a person may claim kinship ties with another. If no limitation were placed on the recognition of kinship, everybody would be kin to everyone else; but in most societies some limitation is imposed on the perception of common ancestry, so that a person regards many of his associates as not his kin. The practical importance of descent comes from its use as a means for one person to assert rights, duties, privileges, or status in relation to another person, who may be related to the first either because one is ancestor to the other or because the two acknowledge a common ancestor. Descent has special influence when rights to succession, inheritance, or residence follow kinship lines. One method of limiting the recognition of kinship is to emphasize the relationships through one parent only. Such unilineal kinship systems, as they are called, are of two main typespatrilineal (or agnatic) systems, in which the relationships through the father are emphasized; and matrilineal (or uxorial) descent systems, in which the maternal relationships are stressed. In systems of double unilineal descent, patrilineal and matrilineal principles operate in the same society, and there are two series of enduring groups, a person belonging to groups in each series. Ambilateral (or ambilineal) descent systems are those in which membership in a kinship group may be claimed through either parent. Unilineal systems differ radically from so-called cognatic systems, in which everyone has obligations and duties of much the same kind toward both his paternal and maternal kin and, conversely, can expect rights and privileges from them. Thus, whereas in a matriliny, for example, a person would feel cousin obligations only to the children of his mother's siblings, in a cognatic system he is in some sense allied to the children of both parents' siblings. The practical significance of this cognatic system may be either that an individual establishes claim on another person of common descent or that he enjoys some status or privilege by virtue of his lineage or descent. Both structurally and in terms of rights and duties, the cognatic system is vague and tends to characterize the more industrialized countries, in which individual rights and duties are defined to an increasing extent institutionally or legally.