Nadeem Huassain sits in for John Perry this episode. Are humans basically irrational? Ken introduces the notion of blindness to the base-rate, which is a negative influence on reasoning. How did humanity come so far if we are so irrational? Ken thinks it is because of evolution. Ken introduces Stephen Stich, professor at Rutgers University. Stich thinks that humans are programmed to be rational in certain contexts. Recent research into rationality has shown that there are many situations in which professionals will consistently reason to the wrong conclusion, such as the Harvard Medical School Problem. Stich says that if the situations are changed to be more familiar, then we reason much more correctly.

Humans can reason well about problems if they are formulated in the right way. Does this help us at all since problems aren't always formulated in the right way? Are these situations illusions? Stich says that the illusion is not easy to remove unless the problems are reformulated. Can we decide to think rationally? Much of modern economic theory is premised on the idea that humans are rationally self-interested agents. Why are logical rules called norms of reasoning since we are so bad at following them? Stich thinks that philosophy has not made progress on reasoning about ends. Are we less rational in groups?

Do emotions detract from rationality or do they form the basis of it? Does our conception of rationality depend upon our cultural base? Nadeem thinks that logical and statistical reasoning makes sense even if you grew up in a radically different culture. Are our ideas of fairness and justice evolutionary adaptations?

• Roving Philosophical Report (Seek to 04:12): Amy talks to an engineer about winning the lottery. Amy also interviews Keith Devlin, a mathematician, about the rationality of human reasoning.

• Sixty Second Philosopher (Seek to 49:42): Ian Shoales covers the history of irrationality from the ancient Greeks to Nietzsche.