Complementary filiation was a term introduced by the group of anthropologists of Africa who are often referred to as ‘descent theorists’, foremost of whom was M. Fortes. The phrase referred to the fact that in societies with unilineal descent groups people nonetheless recognize kinship links with relatives who do not belong to their own descent group. Thus, in societies with patrilineal descent groups, individuals have important socially defined links with members of their mother’s family, such as, for example, their mother’s brother or their maternal grandparents, while in matrilineal societies individuals have similar ties to their father’s family.
Originally the concept was used to describe an important ethnographic characteristic of many African societies, such as the Tallensi of Ghana studied by Fortes, and the anthropologists’ theory was little more than a paraphrase of the theory of the people they had studied. Thus Fortes described how Tallensi individuals saw their complementary filiation links as different from their lineage links, yet essential to their well-being (Fortes 1949). While lineage links always have a political and hierarchical character, complementary filiation is more emotional and more personal. This is because all members of a descent group have different ties of complementary filiation from one another, but are undifferentiated on the basis of descent, so that complementary filiation gives an idiom to feelings of individuality and independence. This sociological perspective is, argued Fortes (1961), also reflected in the religious domain. J. Goody (1962), following in the same tradition, stressed the importance of inheritance and showed how, while one inherited a certain type of property and status inside the descent group, one also inherited different types of property and status along the lines of complementary filiation.
In Fortes’s later work the notion of complementary filiation was used to support a much more general claim (Fortes 1953; 1969). Fortes and a number of other anthropologists argued that the existence of groups was, at bottom, always similar and always involved the recognition of the complementary role of the two parents. Thus, in patrilineal societies, while for political, jural and military purposes lineages ignored links through mothers, there nonetheless existed a domestic level where links through women were recognized in the form of complementary filiation.
It is this wider theoretical implication of the theory which came under attack from such writers as Edmund Leach (1961), who argued that in those patrilineal societies which Levi-Strauss would qualify as having an elementary structure, links through the mother were to be seen, not as manifesting a kind of muted kinship but rather as being part of affinal links. Thus in such societies one’s mother was not seen as a ‘mother’ in the European sense, nor her brother as a man linked to her, but both would be seen as members of the group who give sexual partners to your own group. Such a distinction might seem of little importance but in fact hides a fundamental theoretical claim, namely that there is nothing universal or ‘biological’ to human kinship which constrains its representation.
