In a community economy, expectations of mutuality provide a sense of certainty about material life, and this emerges in social and cultural constructions. For example, some studies suggest that hunting and gathering communities have complete trust in the environment that game will appear. But such expectations, and the rules that make a community, are contingent, for they have no anchorage outside the fact that they are shared by community members. In contrast, competition and the denial of persisting social ties in the market produce uncertainty about livelihood. These endemic features of the market, it may be suggested, produce the drive to amass profit as security for the future. But success in accumulating profit is transitory, for the economic game never ends and capital is always at risk. Unlike the community economy, however, the market is said to have an ultimate grounding in human behaviour, because all market participants are presumed to be rational calculators. According to the accepted model, market behaviour is anchored in human *rationality. Lying outside the market and cultural formulation, this human attribute is used to explain the presence of markets, deny their historical contingency, and provide market participants with the one certainty that others are reasoning calculators, too.