"We tend to ignore how much cognitive effort is required to maintain extreme religious beliefs, which have no supporting evidence whatsoever," says the evolutionary biologist David Sloan Wilson. He likens the process to a cell trying to maintain its osmotic pressure. "You're trying to pump out the mainstream influences all the time. You're trying to maintain this wall, and keep your beliefs inside, and all these other beliefs outside. That's hard work." In some ways, then, at least for fundamentalists, "growing out of it is the easiest thing in the world."A long but very interesting article about priests who lose their faith.
Psychology Today Magazine, Jan/Feb 2008