Most of us have learned to be dispassionate about evil, to look it in the face and find, as often as not, our own grinning reflections with which we do not argue, but good is another matter. Few have stared at that long enough to accept that its face too is grotesque, that in us the good is something under construction. The modes of evil usually receive worthy expression. The modes of good have to be satisfied with a cliche or a smoothing down that will soften their real look.
I told him I was going to betray you, and betray Lyra, and he believed me because I was corrupt and full of wickedness; he looked so deep I felt sure he'd see the truth. But I lied too well. I was lying with every nerve and fiber and everything I'd ever done...I wanted him to find no good in me, and he didn't. There is none.