Anthropologists – as indeed their informants – often stress that gift exchange and commodity exchange are premised on fundamentally opposed principles. In Gregory's neat formulation, for example, gift exchange is seen (following Mauss) as presupposing the interdependence of the parties to the exchange and the inalienability of the gift; while commodity exchange is seen (following Marx) as presupposing the reciprocal independence of the transactors and the alienability of the commodity (Gregory 1982).

This radical contrast between the principles which underlie the two types of exchange is commonly reported as being associated with an equally radical contrast in their moral evaluation. A particularly striking example is provided by Taussig's discussion (1980) of the folklore of the Christianised Black peasantry of the Cauca valley in Columbia. Some peasants who work as wage-labourers on the big sugar plantations are supposed to enter into a pact with the devil by which they increase their production and earn a better wage; but this can only be spent on consumer goods and luxuries, for such money is barren and cannot be productively invested – though some say that it can be made over to friends who can use it for productive ends. Even the cane fields cut by one who has contracted with the devil are rendered infertile. For this reason it is believed that devil contracts are made only by male wage labourers. Peasants working their own plots would not be prepared to lay waste their land by such a deal, while the value women place on fertility and the nurture of children also relieves them of the temptation to make terms with the devil.