My main point was that economics is supposed to be a theory of everyone, not only experts. An expert billiard player might play as if he knows all the relevant geometry and physics, but the typical bar player usually aims at the ball closest to a pocket and shoots, often missing. If we are going to have useful theories about how typical people shop, save for retirement, search for a job, or cook dinner, those theories had better not assume that people behave as if they were experts.
