We did not prove that humans are irrational. I would draw a very important distinction between demonstrating that people are not rational by a particular definition of rationality, especially an absurd one, and claiming that people are irrational. I do not plead guilty; I plead innocent of having ever made the claim that people are irrational. It was made on our behalf more than once. We always regretted it and rejected it. Irrationality conveys something much, much stronger than the view of human nature that Amos Tversky and I ever held.That is from a speech by Daniel Kahneman.