of the mind's universal structures. For him, opposites formed the basis of social structure and culture. Kinship In his early work Lévi-Strauss argued that tribal kinship groups were usually found in pairs, or in paired groups that oppose each other yet need one another. For example, in the Amazon basin, two extended families would build their houses in two facing semicircles that together form a big circle. He showed too that the ways people initially categorized animals, trees, and other natural features, were based on a series of oppositions. In his most popular work, The Raw and the Cooked, he described folk tales of tribal South America as related to one another through a series of transformations—as one opposite in tales here changed into its opposite in tales there. For example, as the title implies, raw becomes its opposite cooked. These particular opposites (raw/cooked) are symbolic of human culture itself, in which by means of thought and labour (economics), raw materials become clothes, food, weapons, art and ideas. While Durkheim thought that taxonomies of the natural world are collective in origin (the "collective conscious"), meaning that social structures influence individual cognitive structures, Lévi-Strauss proposed the opposite, arguing that it is the latter that gives rise to the former. Social structures mirror cognitive structures, meaning that patterns in social interaction can be treated as their manifestations. While structural-functionalists looked for structures within social organisation, structuralism seeks to identify links between structures of thought and social structures. Possibly the most significant influence on structuralism came from Mauss' The Gift. Mauss argued that gifts are not free, but rather oblige the recipient to reciprocate. Through the gift, the givers give part of themselves, imbuing the gift a certain power that compels a response. Gift exchanges, therefore play a crucial role in creating and maintaining social relationships by establishing bonds of obligations. Gifts are not merely physical, incidental objects; they possess cultural and spiritual properties. It is a "total prestation" as Mauss called it, as it carries the power to create a system of reciprocity in which the honour of both giver and recipient are engaged. Social relationships are therefore based on exchange; Durkheimian solidarity, according to Mauss, is best achieved through structures of reciprocity and related systems of exchange. Lévi-Strauss took this idea and postulated three fundamental properties of the human mind: a) people follow rules; b) reciprocity is the simplest way to