Hindus regard all humans as fundamentally unequal. Hindu society is organized around groupings of people into ranked castes. On this there is general agreement, as Dumont's apt characterization, Homo hierarchies, affirms and attests. No similar agreement exists, however, as to the criterion of caste rank. On the one hand, attributional theorists such as H.N.C. Stevenson emphasize the physical nature of a caste and its placement on a continuum of purity and impurity, with the more pure castes held to rank above the less pure. On the other hand, interactional theorists like McKim Marriott emphasize the coded exchange between castes of culturally valued foods and services, with the givers of food held to rank above the receivers, and the receivers of service above the givers; here it is not the religious values of purity and impurity, but behavioral dominance that seems to be at issue.