Recently there as been a surge of interest by researchers in the so-called wisdom of crowds (WoC) effect. Roughly speaking, the WoC effect occurs when a group of people, as a collective, perform some task much better than the individuals in the group.

As exciting as examples of the WoC effect are — e.g., predicting elections, diagnosing rare diseases, and so on — they don’t seem to have much to do with the concept of wisdom, as traditionally understood by philosophers. However, I will argue that there is a class of WoC effects that do correspond to a traditional notion of wisdom and that groups actually do tend to be wiser than their individuals in this traditional sense. To do so, I shall argue for a new interpretation of Socrates on wisdom, generalise it to a Bayesian setting, argue for a revision to the psychologists’ notion of overconfidence to incorporate imprecise probabilities, and present the results of a series of empirical experiments.

The upshot is that, as an empirical fact, groups tend to be wiser than their individuals according to a Bayesian-Socratic understanding of wisdom.