There is a large literature on social epistemology, some of which is concerned with expert knowledge. Formal representations of the aggregation of decisions, estimates, and the like play a larger role in these discussions. Yet these discussions are neither sufficiently social nor epistemic. The assumptions minimize the role of knowledge, and often assume independence between observers. This paper presents a more naturalistic approach, which appeals to a model of epistemic gain from others, as mutual consilience—a genuinely social notion of epistemology. (...) Using the example of Michael Polanyi’s account of science as an illustration, it introduces the notion of double heuristics: that individuals, each with their own heuristics, each with cognitive biases and limitations, are aggregated by a decision procedure, like voting, and this second order procedure produces its own heuristic, with its own cognitive biases and limitations. An example might be the limited ability of democracies to assimilate expert knowledge. (shrink)