“The other side’s got an energy that our side en’t got. Comes from their certainty about being right. If you got that certainty, you’ll be willing to do anything to bring about the end you want. It’s the oldest human problem, Lyra, an’ it’s the difference between good and evil. Evil can be unscrupulous, and good can’t. Evil has nothing to stop it doing what it wants, while good has one hand tied behind its back. To do the things it needs to do to win, it’d have to become evil to do ’em.”
