The Wisdom of the Crowd: The Evidential Role of Convergence and Consensus

While there exists a rich philosophical literature about the epistemological significance of disagreement, agreement is a topic that has received less attention.

The project seeks to fill this lacuna, by examining the question of when, if ever, the fact that some people agree about the truth of some claim is a reason to accept that claim.The project’s first year is devoted the idea that agreement is significant when the thinkers have reached their beliefs independently of each other.

This idea is familiar from Condorcet’s so-called “jury theorem”, but we shall also explore alternative explanations of the value of independence.

The second year focuses on consensus that results from a process of collective deliberation that is often taken to be instantiated in the sciences.

Special attention will be paid to whether such deliberation excludes the kind of independence that is emphasized by the first idea.

The third year, finally, focuses on the question of how arguments from agreement and arguments from disagreement relate to each other.Addressing these questions may lead to progress on neglected issues in the literature, but the project also has a wider relevance.

Climate skeptics and other science deniers tend to explain away expert consensus by attributing it to mechanisms that do not track truth. To respond to such arguments, we need a better understanding of how appeals to consensus are meant to work. The aim of the project is to contribute to such an understanding.