Noah Gabriel Martin

Assessment of those with whom one finds oneself in dispute is indispensable in the epistemology of disagreement. The assessment of one’s opponents is necessary in order to determine whether a particular disagreement constitutes evidence of a likely error in one’s own understanding. However, assessment of an opponent’s capacity to know the matter in dispute is only possible when the conditions for knowledge are not themselves open to debate. Consequently, epistemic significance can only be recognised in disagreements among those who are in tacit or explicit agreement about what constitutes justification in a given case. The result is that the epistemic significance that disagreement possesses is always strictly conditional upon prior assumptions. The difference between a peer disagreement and a non-peer disagreement cannot indicate whether one is or is not more likely to be right than one’s opponent in an absolute sense, only whether one is or is not more likely to be right given the presupposed conditions.

Over the past decade, attention to epistemically significant disagreement has centered on the question of whose disagreement qualifies as significant, but ignored another fundamental question: what is the epistemic significance of disagreement? While epistemologists have assumed that disagreement is only significant when it indicates a determinate likelihood that one’s own belief is false, and therefore that only disagreements with epistemic peers are significant at all, they have ignored a more subtle and more basic significance that belongs to all disagreements, regardless of who they are with—that the opposing party is wrong. It is important to recognize the basic significance of disagreement since it is what explains all manners of rational responses to disagreement, including assessing possible epistemic peers and arguing against opponents regardless of their epistemic fitness.