When Rational Reasoners Reason Differently

Different people reason differently, which means that sometimes they reach different conclusions from the same evidence. We maintain that this is not only natural, but rational. This chapter explores the epistemology of that state of affairs. First it canvasses arguments for and against the claim that rational methods of reasoning must always reach the same conclusions from the same evidence. Then it considers whether the acknowledgment that people have divergent rational reasoning methods should undermine one’s confidence in one’s own reasoning. Finally it explores how agents who employ distinct yet equally rational methods of reasoning should respond to interactions with the products of each others’ reasoning. The chapter finds that the epistemology of multiple reasoning methods has been misunderstood by a number of authors writing on epistemic permissiveness and peer disagreement.