There is a burgeoning literature on social epistemology. Some of it purports to illuminate the problem of expert knowledge. Much of this literature applies epistemological theories, such as reliabilism, to expert claims, which are interpreted in terms of notions familiar to epistemology, such as testimony. Another body of literature is concerned with the contrast between individual and collective rationality or collective knowledge, and is concerned with issues of emergence, specifi cally with the claim that collective knowledge processes are diff erent from and arrive at diff erent and better results than individual knowledge acquisition. Many of these are discussions of collective rationality, and use formal methods. To do so, they typically simplify the issues by assuming independent individual judges. Independence implies epistemic independence, meaning that people act on their own knowledge. Discussions of the related problem of expertise typically follow the same pattern: expertise is compared to testimony, which the individual judges as reliable. The classic prisoner’s dilemma is based explicitly on the mutual ignorance of the prisoners with respect to intentions. Both the social relations between the prisoners and the possibility of sharing knowledge are defi ned away. In this respect, these approaches follow standard economic theories, which assume information equality or otherwise assume the irrelevance of diff erences in quality of information between market participants in market transactions. Nor is there an easy alternative to these assumptions. Asymmetric information theorizing, for example, is technically diffi cult even in small scale transactions with limited dimensions of relevant information, such as theorizing the issues of agency in a used car purchase. Expanding these considerations and expanding considerations of variations between market participants makes calculating outcomes intractable.