We’ve come a long way since ancient times, at least as far as science, technology, and quality of life go. But what about the quality of our beliefs? Have we become any more rational since Socrates? Are we any closer to truth, or at least believe more truth things than we used to? Is Obama any indication that we’ve progressed towards truth, at least a little bit? Can false and true beliefs co-exist?

To help John and Ken get to the heart of the matter, ‘undercover philosopher’ Michael Phillips joins the discussion in this episode (in front of a live audience in Portland!).  It turns out that no matter how far we’ve advanced, we’re still irrational in some troubling ways. For instance, few doctors are well trained in statistics and this makes trouble—unless you take the base rate of a disease into account, a positive test result is meaningless. Nevertheless, patients and doctors alike misinterpret test results constantly because they neglect the base rate and go with their misleading statistical intuitions.

We’ve also got the representative heuristic—we’re likely to think that a glib man in a slick suit is a lawyer and not a doctor, even if we know in advance that there are ten doctors for every lawyer in the room. Just to make it worse, we’re pretty bad at remembering and even perceiving things as well. This makes eyewitness testimony shockingly unreliable, and over 2000 articles to this effect have come out between 1975 and 1999. Sometimes working in groups lets us get past the mistakes that individuals tend to make and keep track of evidence. That’s good, but hardly offers consolation.

Then again, we can also train ourselves to be more rational, by attacking our own ideas with scrutiny and thinking scientifically. But can we ever reach the enlightenment ideal of rationality? Were the great enlightenment thinkers totally wrong? Some were more realistic than others, but will we ever be able to live up to their hopes? How can we deal with the fact that even scientific consensus swings back and forth periodically? Can we ever be certain that our beliefs are rational? John comes up with a pretty good way of handling these issues, but you’d better listen to find out!

• Roving Philosophical Report (seek to 6:41): Julie Napolin talks to Marketing Professor Jill Mosteller to learn more about just how irrational we can be. We like to think that value, taste and cost shape our consumer choices, but is there something else too? It seems that shapes, colors and the placement of a product have a huge, if unconscious influence on us, and we’re not terribly good at shopping rationally. Even if ads aren’t deceptive, they can still take advantage of our irrationality in surprising ways that you might want to learn more about.