The nature of Australian aboriginal social systems has been debated for more than a century and widely divergent interpretations have been offered both for particular cases and for Australian societies in general. The controversy centers on certain systems of classification by means of which the people order their social lives. Three interpretations have predominated. One body of opinion has it that in Australia social relations are governed, by and large if not wholly, by considerations of kinship. Proponents of this interpretation, most notably A. R. Radcliffe-Brown, maintain that Australian social categories are, virtually exhaustively, kinship categories – meaning by “kinship” egocentric relations of genealogical connection. Another interpretation is that in Australia social relations are governed, again by and large if not wholly, by considerations of membership of groups such as lineages, clans, moieties, and sections or subsections – the latter two being known also as “marriage classes.” Proponents of this interpretation argue that those Australian expressions sometimes described as “kinship terms” are more appropriately described as “relationship terms.” The relationships they signify are social and are between groups and individuals as members of groups. A third interpretation attempts to mediate between these two extremes by arguing that, although some Australian societies may be ordered wholly by kinship, most of them are ordered by both kinship and group relations. Where both are present they may be so well integrated that persons acting in kinship capacities are also fulfilling their rights and duties as members of related social groups.