“Revenge and punishment both imply, ‘Even if I’d been you, and I’d had your life, I would never have done what you did.’ And that in turn implies, ‘I wouldn’t have done it, because I’m better than you.’ But the person who says, ‘I’m better than you’ is taking a serious step in a very dangerous direction. And the person who says, ‘Even if I’d had your life, I would never have done what you did’ is very probably wrong.”