In The God Delusion, Dawkins contends that a supernatural creator almost certainly does not exist and that belief in a personal god qualifies as a delusion, which he defines as a persistent false belief held in the face of strong contradictory evidence. He is sympathetic to Robert Pirsig's statement in Lila that "when one person suffers from a delusion it is called insanity. When many people suffer from a delusion it is called religion.