"'Wizard's First Rule: people are stupid.' Richard and Kahlan frowned even more. 'People are stupid; given proper motivation, almost anyone will believe almost anything. Because people are stupid, they will believe a lie because they want to believe it's true, or because they are afraid it might be true. People's heads are full of knowledge, facts, and beliefs, and most of it is false, yet they think it all true. People are stupid; they can only rarely tell the difference between a lie and the truth, and yet they are confident they can, and so are all the easier to fool.
Because of Wizards First Rule, the old wizards created Confessors, and Seekers, as a means of helping find the truth, when the truth is important enough. Darken Rahl knows the Wizard's Rules. He is using the first one. People need an enemy to feel a sense of purpose. It's easy to lead people when they have a sense of purpose. Sense of purpose is more important by far than the truth. In fact, truth has no bearing in this. Darken Rahl is providing them with an enemy, other than himself, a sense of purpose. People are stupid; they want to believe, so they do."
—Chapter 36, p.560, U.S. paperback edition
Of course, I'd be more impressed with this insight if it were not true that (to quote Wikipedia) "Goodkind has been largely influenced by the books of Ayn Rand and is a strong supporter of her works and of Objectivist philosophy." Which is to say, he is the worst sort of victim of Wizard's First Rule.