Harry Potter and the Methods of Rationality

"Indeed," said Harry, "you would expect the Grand Manager of Gringotts to get involved with that much money changing hands. It seems Mr. Weasley was greatly in debt, and so demanded an additional payment of ten thousand Galleons -"

"Ten thousand Galleons for a Weasley? You could buy the daughter of a Noble House for that!"

"Excuse me," Harry said. "I really have to ask at this point, do people actually do that sort of thing around here -"

"Rarely," said Professor Quirrell, with a frown on his face. "And not at all, I suspect, since the Dark Lord departed. I suppose that according to the newspaper, your father just paid it?"

"He didn't have any choice," said Harry. "Not if he wanted to fulfill the conditions of the prophecy."

"Give me that," said Professor Quirrell, and the newspaper leaped out of Harry's hand so fast that he got a paper cut.

Harry automatically put the finger in his mouth to suck on, feeling rather shocked, and turned to remonstrate with Professor Quirrell -

Professor Quirrell had stopped short in the middle of the street, and his eyes were flickering rapidly back and forth as an invisible force held the newspaper suspended before him.

Harry watched, gaping in open awe, as the newspaper opened to reveal pages two and three. And not much long after, four and five. It was like the man had cast off a pretense of mortality.

And after a troublingly short time, the paper neatly folded itself up again. Professor Quirrell plucked it from the air and tossed it to Harry, who caught it in sheer reflex; and then Professor Quirrell started walking again, and Harry automatically trudged after.

"No," said Professor Quirrell, "that prophecy didn't sound quite right to me either."

Harry nodded, still stunned.

"The centaurs could have been put under an Imperius," Professor Quirrell said, frowning, "that seems understandable. What magic can make, magic can corrupt, and it is not unthinkable that the Great Seal of Gringotts could be twisted to another's hand. The Unspeakable could have been impersonated with Polyjuice, likewise the Bavarian seer. And with enough effort it might be possible to tamper with the proceedings of the Wizengamot. Do you have any idea how that was done?"

"I do not have one single plausible hypothesis," said Harry. "I do know it was done on a total budget of forty Galleons."

Professor Quirrell stopped short and whirled on Harry. His expression was now completely incredulous. "Forty Galleons will pay a competent ward-breaker to open a path into a home you wish to burglarize! Forty thousand Galleons might pay a team of the greatest professional criminals in the world to tamper with the proceedings of the Wizengamot!"

Harry shrugged helplessly. "I'll remember that the next time I want to save thirty-nine thousand, nine hundred and sixty Galleons by finding the right contractor."

"I do not say this often," said Professor Quirrell. "I am impressed."

"Likewise," said Harry.

"And who is this incredible Hogwarts student?"

"I'm afraid I couldn't say."

Somewhat to Harry's surprise, Professor Quirrell made no objection to this.

They walked in the direction of the Gringotts building, thinking, for they were neither of them the sort of person who would give up on the problem without considering it for at least five minutes.

"I have a feeling," Harry said finally, "that we're coming at this from the wrong angle. There's a tale I once heard about some students who came into a physics class, and the teacher showed them a large metal plate near a fire. She ordered them to feel the metal plate, and they felt that the metal nearer the fire was cooler, and the metal further away was warmer. And she said, write down your guess for why this happens. So some students wrote down 'because of how the metal conducts heat', and some students wrote down 'because of how the air moves', and no one said 'this just seems impossible', and the real answer was that before the students came into the room, the teacher turned the plate around."

"Interesting," said Professor Quirrell. "That does sound similar. Is there a moral?"

"That your strength as a rationalist is your ability to be more confused by fiction than by reality," said Harry. "If you're equally good at explaining any outcome, you have zero knowledge. The students thought they could use words like 'because of heat conduction' to explain anything, even a metal plate being cooler on the side nearer the fire. So they didn't notice how confused they were, and that meant they couldn't be more confused by falsehood than by truth. If you tell me that the centaurs were under the Imperius Curse, I still have the feeling of something being not quite right. I notice that I'm still confused even after hearing your explanation."

"Hm," said Professor Quirrell.

They walked on further.

"I don't suppose," said Harry, "that it's possible to actually swap people into alternate universes? Like, this isn't our own Rita Skeeter, or they temporarily sent her somewhere else?"

"If that was possible," Professor Quirrell said, his voice rather dry, "would I still be here?"

And just as they were almost to the huge white front of the Gringotts building, Professor Quirrell said:

"Ah. Of course. I see it now. Let me guess, the Weasley twins?"

"What?" said Harry, his voice going up another octave in pitch. "How?