Evolution, Rationality, and Coherence Criteria

How much irrationality should we ascribe to human cognition? Psychological evidence suggests that people’s reasoning is largely inaccurate, but according to an evolutionary argument for rationality (henceforth, EAR), we have good reasons to believe that this is not so. To solve the conflict between psychological evidence and EAR, commentators have usually put the blame either on the psychological evidence, arguing that inaccurate reasoning appears only in the context of lab studies, or on the premises of EAR, charged with not being in line with the concepts and findings of evolutionary biology. I argue that Hammond’s distinction between two distinct criteria of rationality, namely coherence and correspondence, might shed new light on this apparent conflict. I show that EAR might be interpreted in two different ways, and that EAR and psychological evidence might in fact be both correct if they appeal to different criteria of accurate reasoning. Moreover, evolutionary considerations have been recently used not to oppose the existence of violations of norms of coherence but rather to explain it.