Harry Potter and the Methods of Rationality

fifteen minutes do not stand up and graciously forgive their enemies. It is the sort of thing you do when you're trying to convince everyone you're not Dark, not -'

'I can't believe this! You can't have every possible observation confirm your theory! '

'And that was a trifle too much indignation.'

'What on Earth do I have to do to convince you?'

'To convince me that you harbor no ambitions of becoming a Dark Lord?' said Professor Quirrell, now looking outright amused. 'I suppose you could just raise your right hand.'

'What?' Harry said blankly. 'But I can raise my right hand whether or not I -' Harry stopped, feeling rather stupid.

'Indeed,' said Professor Quirrell. 'You can just as easily do it either way. There is nothing you can do to convince me because I would know that was exactly what you were trying to do. And if we are to be even more precise, then while I suppose it is barely possible that perfectly good people exist even though I have never met one, it is nonetheless improbable that someone would be beaten for fifteen minutes and then stand up and feel a great surge of kindly forgiveness for his attackers. On the other hand it is less improbable that a young child would imagine this as the role to play in order to convince his teacher and classmates that he is not the next Dark Lord. The import of an act lies not in what that act resembles on the surface, Mr. Potter, but in the states of mind which make that act more or less probable.'

Harry blinked. He'd just had the dichotomy between the representativeness heuristic and the Bayesian definition of evidence explained to him by a wizard.

'But then again,' said Professor Quirrell, 'anyone can want to impress their friends. That need not be Dark. So without it being any kind of admission, Mr. Potter, tell me honestly. What thought was in your mind at the moment when you forbade any vengeance? Was that thought a true impulse to forgiveness? Or was it an awareness of how your classmates would see the act?'

Sometimes we make our own phoenix song.

But Harry didn't say it out loud. It was clear that Professor Quirrell wouldn't believe him, and would probably respect him less for trying to utter such a transparent lie.

After a few moments of silence, Professor Quirrell smiled with satisfaction. 'Believe it or not, Mr. Potter,' said the professor, 'you need not fear me for having discovered your secret. I am not going to tell you to give up on becoming the next Dark Lord. If I could turn back the hands of time and somehow remove that ambition from the mind of my child self, the self of this present time would not benefit from the alteration. For as long as I thought that was my goal, it drove me to study and learn and refine myself and become stronger. We become what we are meant to be by following our desires wherever they lead. That is the insight of Salazar. Ask me to show you to the library section which holds those same books I read as a thirteen-year-old, and I will happily lead the way.'

'For the love of crap,' Harry said, and sat down on the hard marble floor, and then lay back on the floor, staring up at the distant arches of the ceiling. It was as close as he could come to collapsing in despair without hurting himself.

'Still too much indignation,' observed Professor Quirrell. Harry wasn't looking but he could hear the suppressed laughter in the voice.

Then Harry realized.

'Actually, I think I know what's confusing you here,' Harry said. 'That was what I wanted to talk to you about, in fact. Professor Quirrell, I think that what you're seeing is my mysterious dark side.'

There was a pause.

'Your... dark side...'

Harry sat up. Professor Quirrell was regarding him with one of the strangest expressions Harry had seen on anyone's face, let alone anyone as dignified as Professor Quirrell.

'It happens when I get angry,' Harry explained. 'My blood runs cold, everything gets cold, everything seems perfectly clear... In retrospect it's been with me for a while - in my first year of Muggle school, someone tried to take away my ball during recess and I held it behind my back and kicked him in the solar plexus which I'd read was a weak point, and the other kids didn't bother me after that. And I bit a math teacher when she wouldn't accept my dominance. But it's only just recently that I've been under enough stress to notice that it's an actual, you know, mysterious dark side, and not just an anger management problem like the school psychologist said. And I don't have any super magical powers when it happens, that was one of the first things I checked.'

Professor Quirrell rubbed his nose. 'Let me think about this,' he said.

Harry waited in silence for a full minute. He used that time to stand up, which was more difficult than he had expected.

'Well,' Professor Quirrell said after a while. 'I suppose there was something you could say that would convince me.'

'I have already guessed that my dark side is really just another part of me and that the answer isn't to never become angry but to learn to stay in control by accepting it, I'm not dumb or anything and I've seen this story enough times to know where it's going, but it's hard and you seem like the person to help me.'

'Well... yes... very perspicacious of you, Mr. Potter, I must say... that side of you is, as you seem to have already surmised, your intent to kill, which as you say is a part of you...'

'And needs to be trained,' Harry said, completing the pattern.

'And needs to be trained, yes.' That strange expression was still on Professor Quirrell's face. 'Mr. Potter, if you truly do not wish to be the next Dark Lord, then what was the ambition which the Sorting Hat tried to convince you to abandon, the ambition for which you were Sorted into Slytherin?'

'I was Sorted into Ravenclaw!'