Harry Potter and the Methods of Rationality

by Eliezer Yudkowsky

  Harry climbed up onto his uncomfortable wooden stool, thinking Subtle in a tone of some mental sarcasm, and awaited his creditors.

  It was only a brief interval later, much shorter than the time a debtor could legally be made to wait, when Lucius Malfoy entered into the room, taking up his leather chair with motions worn smooth by practice. His snake-headed cane was missing from his hands, his long white mane drifted behind him the same as ever, his face could not be read.

  Quietly following behind him was a young boy with white-blonde hair, now wearing black robes far finer than any Hogwarts uniform, who followed in his father's footsteps with a controlled face. A boy who was also Harry's creditor to the tune of forty Galleons, and also of House Malfoy, and therefore, technically, covered by the Wizengamot resolution enabling this meeting.

  Draco. Harry didn't say it aloud, didn't let his own expression change. He could not think of what to say. Not even I'm sorry seemed appropriate. Harry hadn't dared say any of that to Draco's Patronus either, when they had set up this meeting in a few brief exchanges; and not only because Lucius might be listening. It had been enough to know that Draco's happy thought was still happy, and that he had still been able to want Harry to know it.

  Lucius Malfoy spoke first, his voice level, his face set. "I do not understand what is happening at Hogwarts, Harry Potter. Would you care to explain it to me?"

  "I don't know," Harry said. "If I understood these events I would not have let them happen, Lord Malfoy."

  "Then answer me this question. Who are you?"

  Harry gazed evenly at the face of his creditor. "I'm not You-Know-Who, like you thought I was," Harry said. Not being a complete idiot, he'd eventually worked out who Lucius Malfoy had thought he was talking to in front of the Wizengamot. "Obviously I'm not a normal boy. Equally obviously, that probably has something to do with the Boy-Who-Lived business. But I don't know what, or why, any more than you do. I asked the Sorting Hat and it didn't know either."

  Lucius Malfoy nodded distantly. "I could not think of any reason why you would pay a hundred thousand Galleons to save a mudblood's life. No reason save one, which would account for her power and bloodthirst alike; but then she died at the hands of a troll, and yet you lived. And also my son has told me much of you, Harry Potter, which did not make the tiniest bit of sense, I have heard the ravings of the mad in St. Mungo's and they were more sensible by far than the events which my son told me under Veritaserum that you enacted, and that portion of this raving lunacy, which you personally carried out, I would have you explain to me, and now."

  Harry turned to look at Draco, who looked back at him with a face that was screwing up, being controlled, and then tensing up again.

  "I'd also," Draco Malfoy said in a high and wavering voice, "like, to know, why, Potter."

  Harry closed his eyes, and spoke without looking. "A boy raised by Muggles who thought he was clever. You saw me, Draco, and you thought of how very useful it would be if the Boy-Who-Lived, out of all the other children in your year, could be shown the truth of things, if we could be friends. And I thought the same thing about you. Only, you and I believed different things were true. Not that I'm saying that there are different truths, I mean, there's different beliefs but there's only one reality, only one universe that can make those beliefs true or false -"

  "You lied to me."

  Harry opened his eyes and looked at Draco. "I would prefer to say," Harry said, not quite with a steady voice, "that the things I told you were true from a certain point of view."

  "A certain point of view?" Draco Malfoy looked every bit as angry as Luke Skywalker'd had the right to be, and not in a mood to accept Kenobi's excuses, either. "There's a word for things that are true from a certain point of view. They're called lies!"

  "Or tricks," Harry said evenly. "Statements which are technically true but which deceive the listener into forming further beliefs which are false. I think it's worth making that distinction. What I told you was a self-fulfilling prophecy; you believed that you couldn't deceive yourself, so you didn't try. The skills you've learned are real, and it would have been very bad for you to start fighting against them internally. People can't make themselves believe that blue is green by an act of will, but they think they can, and that can be almost as bad."

  "You used me," said Draco Malfoy.

  "I only used you in ways that made you stronger. That's what it means to be used by a friend."

  "Even I know that's not what friendship is!"

  Now Lucius Malfoy spoke again. "For what purpose? To what end?" Even the elder Malfoy's voice was not quite steady. "Why?"

  Harry regarded him for a moment, and then turned to Draco. "Your father's probably not going to believe this," Harry said. "But you, Draco, should be able to see that everything which has happened is compatible with this hypothesis. And that any more cynical hypothesis wouldn't explain why I didn't press you harder when you thought I had leverage, or why I taught you so much. I thought that the heir of House Malfoy, who'd been publicly seen to grab a Muggleborn girl to stop her falling off the roof of Hogwarts, would be a good compromise candidate to lead magical Britain after the reformation."

  "So you would have me believe," Lucius Malfoy said in a thin voice, "that you are claiming to be mad. Well, let us leave all that aside. Tell me who set that troll on Hogwarts."

  "I don't know," Harry said.

  "Tell me who you suspect, Harry Potter."

  "I have four suspects. One of them is Professor Snape -"

  "Snape?" Draco burst out.

  "The second, of course, is the Defense Professor of Hogwarts, just because he's the Defense Professor." Harry would have left him out, not wanting to bring Professor Quirrell to the Malfoys' attention if he was innocent, but Draco might have called him on that. "The third, you wouldn't believe me about. The fourth is a catchall category called Everything Else." And the fifth, Lord Voldemort, I do not think I should name to you.

  Lucius Malfoy's face contorted in a snarl. "Do you think I cannot recognize bait upon your hook? Tell me about this third possibility, Potter, the one you wish me to believe is the true answer, and leave aside games."

  Harry regarded Lord Malfoy steadily. "I once read a book I wasn't supposed to read, and it told me this: Communication is an event that takes place between equals. Employees lie to their bosses, who, in turn, expect to be lied to. I'm not playing coy, I'm observing that it's simply not possible, in our present situation, for me to tell you about the third suspect, and have you believe that my story was anything but a lure."

  Draco spoke then. "It's Father, isn't it?"

  Harry gave Draco a startled look.

  Draco spoke evenly. "You suspect that Father sent the troll into Hogwarts to get at Granger, don't you? That's what you're thinking, isn't it!"

  Harry opened his mouth to say, Actually, no, and then managed to think ahead and stop himself for once in his life.

  "I see..." Harry said slowly. "That's what this is about. Lucius Malfoy publicly says that Hermione won't get away with what she's done, and lo and behold, a troll kills her." Harry smiled then, in a way that bared his teeth. "And if I deny that here, then Draco, who isn't an Occlumens, can then testify under Veritaserum that the Boy-Who-Lived does not suspect Lucius Malfoy of having sent a troll into Hogwarts to kill Hermione Granger, sworn to the Noble House of Potter, whose blood debt was recently purchased for a hundred thousand Galleons et cetera." Harry leaned back slightly, though his wooden stool had no back with which to do it properly. "But now that it's been pointed out, I see that it's very reasonable. Obviously you killed Hermione Granger, just like you threatened to do in front of the whole Wizengamot."

  "I did not," Lucius Malfoy said, expressionless once more.

  Harry bared his teeth again in that non-smile. "Well then, in that case, there must be someone else out there who killed Hermione and messed with the Hogwarts wards, the same person who earlier tried to frame Hermione for Draco Malfoy's murder. Either you ki
lled Hermione Granger after being paid for her life, or you blamed your son's attempted murder on an innocent girl and took all my family's money under false pretenses, one of those two things must be true."

  "Perhaps you killed her in hopes of your money being returned." Lucius Malfoy had leaned forward, and was staring hard at Harry.

  "Then I would not have given away my money for her in the first place. As you already know. Don't insult my intelligence, Lord Malfoy - no, wait, sorry, you just had to say that in case Draco had to testify to it, never mind."

  Lucius Malfoy sat back in his chair and stared.

  "I tried to tell you, Father," Draco said under his breath, "but nobody can imagine Harry Potter until they've actually met him..."

  Harry tapped a finger on his cheek. "So people are starting to figure out the blatantly obvious? I'm surprised, actually. I wouldn't have predicted that would happen." Harry had by now caught the general rhythm of Professor Quirrell's cynicism and was able to generate it independently. "I wouldn't think a newspaper would be able to report on a concept like 'Either X or Y must be true, but we don't know which.' I would only expect journalists to report stories consisting of series of atomic propositions, like 'X is true', 'Y is false', or 'X is true and Y is false'. Not more complex logical connectors like 'If X is true then Y is true, but we don't know whether X is true'. And all your supporters ought to be rapidly switching between 'You can't prove that Lord Malfoy killed Granger, it could've been someone else' and 'You can't prove there was someone else to frame Granger', so long as it's uncertain they should be trying to have it both ways at once... wait, don't you own the Daily Prophet?"

  "The Daily Prophet," Lucius Malfoy said thinly, "which I certainly do not own, is far too respectable to publish any such scurrilous nonsense. Unfortunately, not all wizards of influence are so reasonable."

  "Ah. Got it." Harry nodded.

  Lucius glanced at Draco. "The rest of what he said - was any of it important?"

  "No, Father, it was not."

  "Thank you, son." Lucius returned his gaze to Harry. His voice, when he spoke, was something closer to his usual drawl, cool and confident. "It is possible that I could be persuaded to show you some favor, if you admitted before the Wizengamot what you clearly know, that I was not responsible for this deed. I would be willing to reduce your remaining debt to House Malfoy quite significantly, or even adjust the terms to allow later repayment."

  Harry regarded Lucius Malfoy steadily. "Lucius Malfoy. You are now perfectly aware that Hermione Granger was, in fact, framed using your son as bait, that she was False-Memory-Charmed or worse, and that House Potter held nothing against you before that. My counterproposal is that you return my family's money, I announce before the Wizengamot that House Potter holds House Malfoy no animus, and we present a united front against whoever's doing this. We decide to screw the roles we're supposed to play, and ally with each other instead of fighting. It could be the one thing the enemy doesn't expect us to do."

  There was a brief silence in the room, except for the two goblin guards who went on breathing regardless.

  "You are mad," Lucius Malfoy said coldly.

  "It's called justice, Lord Malfoy. You cannot possibly expect me to cooperate with you while you are holding the wealth of House Potter under what you now know to be false pretenses. I understand how it looked to you at the time, but you know better now."

  "You have nothing to offer me worth a hundred thousand Galleons."

  "Don't I?" Harry said distantly. "I wonder. I think it quite probable that you care more about the long-term welfare of House Malfoy than about whichever political issue the last generation's failed Dark Lord made his personal hobbyhorse." Harry glanced significantly at Draco. "The next generation is drawing its own battle lines and forming new alliances. Your son can be frozen out of that, or he can go straight to the top. Is that worth more to you than forty thousand Galleons you weren't particularly expecting and don't particularly need?" Harry smiled thinly. "Forty thousand Galleons. Two million Muggle pounds sterling. Your son knows some things about the size of the Muggle economy that might surprise you. They'd find it amusing, that the fate of a country was revolving around two million pounds sterling. They'd think it was cute. And I think much the same, Lord Malfoy. This isn't about me being desperate. This is about you getting a fair chance to be fair."

  "Oh?" said Lord Malfoy. "And if I refuse your fair chance, what then?"

  Harry shrugged. "Depends what sort of coalition government gets put together without the Malfoys. If the government can be reformed peacefully and it would disturb the peace to do otherwise, I'll pay you the money out of petty cash. Or maybe the Death Eaters will be retried for past crimes and executed as a matter of justice, as a result of due legal process, of course."

  "You truly are mad," Lucius Malfoy said quietly. "You have no power, no wealth, and yet you say such things to me."

  "Yes, it's silly to think I could scare you. After all, you're not a Dementor."

  And Harry went on smiling. He'd looked it up, and apparently a bezoar would heal almost any poison if you shoved it into someone's mouth fast enough. Maybe that wouldn't repair radiation damage from Transfigured polonium, but then again, maybe it would. So Harry had looked up the freezing points of various acids, and it turned out that sulfuric acid would freeze at just ten degrees Celsius, which meant Harry could buy a liter of acid on the Muggle market, freeze it solid, and Transfigure it down to a tiny little unnoticable water-ice chip to be flipped into someone's mouth and ingested. No bezoar would compensate for that, once the Transfiguration wore off. Harry had no intention of saying it out loud, of course, but now that he'd failed decisively to prevent any deaths during his quest, he had no further intention of being restrained by the law or even the code of Batman.

  Last chance to live, Lucius. Ethically speaking, your life was bought and paid for the day you committed your first atrocity for the Death Eaters. You're still human and your life still has intrinsic value, but you no longer have the deontological protection of an innocent. Any good person is licensed to kill you now, if they think it'll save net lives in the long run; and I will conclude as much of you, if you begin to get in my way. Whoever sent the troll after Granger must have targeted you too and hit you with some curse that makes former Death Eaters melt into a pile of goo. Very sad.

  "Father," Draco said in a small voice. "I think you should consider it, father."

  Lucius Malfoy looked at his son. "You jest."

  "It's true. I don't think Potter just made up his books, nobody could have written all that and there were things in them that I could check for myself. And if even half of all that is true, he's right, a hundred thousand Galleons won't mean much. If we give it to him he really will be friends with House Malfoy again - the way he thinks of being friends, anyway. And if we don't, he'll be your enemy, whether it's in his own interests or not, he'll just go after you. Harry Potter really does think like that. It's not about money to him, it's about what he thinks is honor."

  Harry Potter inclined his head, still smiling.

  "But let's get one part of it straight," Draco said, now staring directly at him. There was a fierce light in his eyes. "You wronged me. And you owe me."

  "Acknowledged," Harry said quietly. "Conditional on the rest of it, of course."

  Lucius Malfoy opened his mouth to say who-knew-what and then closed it again. "Mad," he said again.

  There was a long father-and-son argument during which Harry managed to keep his mouth shut.

  When it seemed that even Draco wouldn't be able to persuade his father, Harry spoke up again, and proposed his intended next steps, if the Houses of Potter and Malfoy could cooperate.

  Then came more argument between Lucius and Draco, during which Harry again stayed silent.

  Finally Lucius Malfoy's eyes turned to gaze at Harry. "And you believe," Lucius Malfoy said, "that you can persuade Longbottom and Bones to go along with this notion, even if Dumbledore opposes it."r />
  Harry nodded. "They'll be suspicious of your involvement, of course. But I'll tell them that it was my plan to start with, and that should help."

  "I suppose," Lucius Malfoy said after a pause, "that I could have a contract drawn up, absolving you of almost all the remaining debt, if by some chance I do go along with this mad idea. It shall need more guarantees, of course -"

  Harry promptly reached into his robes and drew out a parchment, unfolding it and spreading it across the golden table. "I've taken the liberty myself, actually," Harry said. He'd spent some careful hours in the Hogwarts library with the law books available. Thankfully, so far as Harry could tell, the laws of magical Britain were charmingly simple by Muggle standards. Writing that the original blood debt and payment was cancelled, the Potters' wealth and all other vault items would be returned, and the remaining debt annulled, all with no fault to the Malfoys, was only a few more lines than it took to say out loud. "I had to promise my keepers not to sign anything you gave me. So I made sure to compose this myself, and sign it before I left."

  Draco emitted a choked laugh.

  Lucius read through the contract, smiling humorlessly. "How charmingly straightforward."

  "I also promised not to touch a quill while I was in Gringotts," Harry said. He reached into his robes again and drew out a Muggle pen, along with a sheet of normal paper. "Will this wording be all right?" Harry rapidly scribbled down a legal-sounding statement to the effect that House Potter didn't hold House Malfoy responsible in any way for Hermione Granger's murder and didn't believe they had anything to do with it, then held up the paper in the air for Lord Malfoy's inspection.