The Bayes' Theorem

May: I want to get into some of those broader contemporary societal questions we face in which reason seems to be under challenge. You spend a lot of time in the book explaining what reason is, how it works, how we exercise it and how sometimes we don't. May: One of the tools of reasoning that every educated person should have at their fingertips is a simple rule called Bayes' Rule or Bayes' Theorem. People are famously ignorant of it, or at least they tend to go just with stereotypes of what it is like if the hypothesis is true without taking into account how likely it was in first place.