In a new book, The Enigma of Reason:ANewTheoryof HumanUnderstanding, the cognitive scientists Hugo Mercier and Dan Sperber take a stab at answering this question. Mercier, who works at a French research institute in Lyon, and Sperber, now based at the Central European University, in Budapest, point out that reason is an evolved trait, like bipedalism or three-colour vision. It emerged on the African savannahs.
Stripped of a lot of what might be called cognitive-scienceese, Mercier and Sperber’s argument runs, more or less, as follows: humans’ biggest advantage over other species is our ability to cooperate. Cooperation is difficult to establish and almost as difficult to sustain. And, for any individual, freeloading is always the best course of action.
Reason developed not to enable us to solve abstract, logical problems or even to help us drawconclusionsfromunfamiliar data; rather, it developed to resolve the problems posed by living in collaborative groups. “Reason is an adaptation to the hypersocial niche humans have evolved for themselves,” Mercier and Sperber write.
Habits of mind that seem weird or goofy or just plain dumb from an “intellectualist” point of view prove shrewd when seen from a social “interactionist” perspective. Consider what is become known as “confirmation bias”, the tendency people have to embrace information that supports their beliefs and reject information that contradicts them.
From “Why Facts Don’t Change Our Minds”