the differences that contrast it with others, the limits by which it defines itself and encloses itself upon its own coherence, within the dimension in which its relations occur with each of the three great positivities (life, need and labour, and language): thus, ethnology shows how, within a given culture, there occur the normalization of the broad biological functions, the rules that render possible or obligatory all the forms of exchange, production, and consumption, and the systems that are organized around or on the model of linguistic structures.