Following up to “Why do I want to believe this?“.
According to Hugo Mercier
Dan Sperber came up with the idea that reasoning doesn’t have this function of helping us get better beliefs and make better decisions. Instead, reasoning is for argumentation. Dan’s basic idea is that the function of reasoning, the reason it evolved, is to help us convince other people and to evaluate their arguments.
Here we have a radically different idea that stands apart from the common wisdom in psychology, cognitive science, and even in philosophy. In Western thought, for at least the last couple hundred years, people have thought that reasoning was purely for individual reasons. But Dan challenged this idea and said that it was a purely social phenomenon and that the goal was argumentative, the goal was to convince others and to be careful when others try to convince us.
And the beauty of this theory is that not only is it more evolutionarily plausible, but it also accounts for a wide range of data in psychology. Maybe the most salient of phenomena that the argumentative theory explains is the confirmation bias.
But advertising and other unreason seem to be much more powerful than reason in the arena of human influence. The road to Damascus bypasses reason.
If the goal of reason is “to convince others and to be careful when others try to convince us”, then it’s doing a lousy job.