A recent article in Behavioral and Brain Sciences explores the question "Why do humans reason? Arguments for an argumentative theory".
Hugo Mercier and Dan Sperber argue that people do not reason as a means of acquiring knowledge or making better decisions. Rather, reasoning evolved for a rhetorical reason—to persuade. The authors note:
Reasoning can lead to poor outcomes not because humans are bad at it but because they systematically look for arguments to justify their beliefs or their actions…. Human reasoning is not a profoundly flawed general mechanism; it is a remarkably efficient specialized device adapted to a certain type of social and cognitive interaction at which it excels. (p. 72)
If this evolutionary theory is borne out by further experiments, how would this affect Kantian ethics, which places special emphasis on reasoning as a way of acquiring knowledge?