"Didn't you finish your chemistry in school?" "You closed the school and burnt all the books." "Ah, so I did." - Patrick Ness

I didn’t mean it,” Conor said. You did, the monster said, but you also did not. Conor sniffed and looked up to its face, which was as big as a wall in front of him. “How can both be true?” Because humans are complicated beasts, the monster said. How can a queen be both a good witch and a bad witch? How can a prince be a murderer and a saviour? How can an apothecary be evil-tempered but right-thinking? How can a parson be wrong-thinking but good-hearted? How can invisible men make themselves more lonely by being seen?

Conor O’Malley who wants to be punished,” Harry said, still stepping back, his eyes on Conor’s. “Conor O’Malley who needs to be punished. And why is that, Conor O’Malley? What secrets do you hide that are so terrible?

And changing for the better doesn't mean that he's ever going to reach good.