Most fundamentalists sell certainty. Fundamentalist Christians sell certainty and ground their certainty in the Bible. Fundamentalist Muslims sell certainty and ground their certainty in the Koran. Fundamentalist atheists sell certainty and ground their certainty in science. Fundamentalist agnostics sell certainty and ground their certainty in perpetual doubt. So the bottom line is that certainty sells. No one wants to live in uncertainty. No one wants to have this cognitive dissonance, this civil war