As a preamble to next week's interview with neurologist and neuroskeptic Robert Burton, I re-aired this earlier conversation with Bob from 2008. In it, we discussed his book "On Being Certain: Believing You're Right Even When You're Wrong," about our brain's often unreliable sense of self-certainty. Bob says our inner sensation of knowing or not knowing something, of familiarity or unfamiliarity – so critical to perception, judgment and decisionmaking – is based on neural mechanisms that can go badly awry and, even when things are working OK, is hardly a dependable arbiter of truth.