Religious fundamentalism is not the only aberration of this type, political zealotry falls into the same category, as well as certain philosophical beliefs. Sometimes it goes into even crazier dimensions, such as fanaticism for a sports team, or for a particular type of music or art. Or it can express itself as a perverse form of natural love, such as admiration of a leader, or of a group, such as a gang, or race, or country.

I mean, I love rock and roll and hate the New York Yankees like any decent human being should, and I put up with crap from my relatives I wouldn't take from anyone else; but I don't wish death or bodily injury to those who disagree with me. People do get into fights at ball games.

The problem is not about what we believe in, everyone believes in a lot of things we can't prove to be true, even things no one can prove to be true. The problem lies when we need our belief to be a universal truth because it fulfills some psychological or social need, when denying that belief attacks or threatens us. And when the need to believe manifests itself as hatred for those who do not, look out. That's the lizard brain at work.