Harry Potter and the Methods of Rationality

by Eliezer Yudkowsky

  "No," said the Professor in her precise Scottish accent, "but please explain, Mr. Potter, if you would be so kind."

  "Well..." Harry said, trying to figure out how to describe that particular bit of Muggle science. "Suppose you come into work and see your colleague kicking his desk. You think, 'what an angry person he must be'. Your colleague is thinking about how someone bumped him into a wall on the way to work and then shouted at him. Anyone would be angry at that, he thinks. When we look at others we see personality traits that explain their behaviour, but when we look at ourselves we see circumstances that explain our behaviour. People's stories make internal sense to them, from the inside, but we don't see people's histories trailing behind them in the air. We only see them in one situation, and we don't see what they would be like in a different situation. So the fundamental attribution error is that we explain by permanent, enduring traits what would be better explained by circumstance and context." There were some elegant experiments which confirmed this, but Harry wasn't about to go into them.

  The witch's eyebrows drew up beneath her hat's brim. "I think I understand..." Professor McGonagall said slowly. "But what does that have to do with you?"

  Harry kicked the brick wall of the alley hard enough to make his foot hurt. "People think that I saved them from You-Know-Who because I'm some kind of great warrior of the Light."

  "The one with the power to vanquish the Dark Lord..." murmured the witch, a strange irony leavening her voice.

  "Yes," Harry said, annoyance and frustration warring in him, "like I destroyed the Dark Lord because I have some kind of permanent, enduring destroy-the-Dark-Lord trait. I was fifteen months old at the time! I don't know what happened, but I would suppose it had something to do with, as the saying goes, contingent environmental circumstances. And certainly nothing to do with my personality. People don't care about me, they aren't even paying attention to me, they want to shake hands with a bad explanation." Harry paused, and looked at McGonagall. "Do you know what really happened?"

  "I have formed an idea..." said Professor McGonagall. "After meeting you, that is."

  "Yes?"

  "You triumphed over the Dark Lord by being more awful than he was, and survived the Killing Curse by being more terrible than Death."

  "Ha. Ha. Ha." Harry kicked the wall again.

  Professor McGonagall chuckled. "Let's get you to Madam Malkin's next. I fear your Muggle clothing may be attracting attention."

  They ran into two more well-wishers along the way.

  Madam Malkin's Robes had a genuinely boring shopfront, red ordinary brick, and glass windows showing plain black robes within. Not robes that shone or changed or spun, or radiated strange rays that seemed to go right through your shirt and tickle you. Just plain black robes, that was all you could see through the window. The door was propped wide open, as if to advertise that there were no secrets here and nothing to hide.

  "I'm going to go off for a few minutes while you get fitted for your robes," said Professor McGonagall. "Will you be all right with that, Mr. Potter?"

  Harry nodded. He hated clothes shopping with a fiery passion and couldn't blame the older witch for feeling the same way.

  Professor McGonagall's wand came out of her sleeve, tapped Harry's head lightly. "And as you'll need to be clear to Madam Malkin's senses, I am removing the Obfuscation."

  "Uh..." Harry said. That did worry him a little; he still wasn't used to the 'Harry Potter' thing.

  "I went to Hogwarts with Madam Malkin," McGonagall said. "Even then, she was one of the most composed people I knew. She wouldn't turn a hair if You-Know-Who himself walked into her shop." McGonagall's voice was reminiscent, and very approving. "Madam Malkin won't bother you, and she won't let anyone else bother you."

  "Where are you going?" Harry inquired. "Just in case, you know, something does happen."

  McGonagall gave Harry a hard look. "I am going there," she said, pointing at a building across the street which showed the sign of a wooden keg, "and buying a drink, which I desperately need. You are to get fitted for your robes, nothing else. I will come back to check up on you shortly, and I expect to find Madam Malkin's shop still standing and not in any way on fire."

  Madam Malkin was a bustling old woman who didn't say a word about Harry when she saw the scar on his forehead, and she shot a sharp look at an assistant when that girl seemed about to say something. Madam Malkin got out a set of animated, writhing bits of cloth that seemed to serve as tape measures and set to work examining the medium of her art.

  Next to Harry, a pale young boy with a pointed face and awesomecool blonde-white hair seemed to be going through the final stages of a similar process. One of Malkin's two assistants was examining the white-haired boy and the chequerboard-gridded robe he was wearing; occasionally she would tap a corner of the robe with her wand, and the robe would loosen or tighten.

  "Hello," said the boy. "Hogwarts, too?"

  Harry could predict where this conversation was about to go, and he decided in a split second of frustration that enough was enough.

  "Good heavens," whispered Harry, "it couldn't be." He let his eyes widen. "Your... name, sir?"

  "Draco Malfoy," said Draco Malfoy, looking slightly puzzled.

  "It is you! Draco Malfoy. I - I never thought I'd be so honoured, sir." Harry wished he could make tears come out of his eyes. The others usually started crying at around this point.

  "Oh," said Draco, sounding a little confused. Then his lips stretched in a smug smile. "It's good to meet someone who knows his place."

  One of the assistants, the one who'd seemed to recognise Harry, made a muffled choking sound.

  Harry burbled on. "I'm delighted to meet you, Mr. Malfoy. Just unutterably delighted. And to be attending Hogwarts in your very year! It makes my heart swoon."

  Oops. That last part might have sounded a little odd, like he was flirting with Draco or something.

  "And I am pleased to learn that I shall be treated with the respect due to the family of Malfoy," the other boy lobbed back, accompanied by a smile such as the highest of kings might bestow upon the least of his subjects, if that subject were honest, though poor.

  Eh... Damn, Harry was having trouble thinking up his next line. Well, everyone did want to shake the hand of Harry Potter, so - "When my clothes are fitted, sir, might you deign to shake my hand? I should wish nothing more to put the capper upon this day, nay, this month, indeed, my whole lifetime."

  The white-blonde-haired boy glared in return. "And what have you done for the Malfoys that entitles you to such a favour?"

  Oh, I am so totally trying this routine on the next person who wants to shake my hand. Harry bowed his head. "No, no, sir, I understand. I'm sorry for asking. I should be honoured to clean your boots, rather."

  "Indeed," snapped the other boy. His stern face lightened somewhat. "Tell me, what House do you think you might be sorted into? I'm bound for Slytherin House, of course, like my father Lucius before me. And for you, I'd guess House Hufflepuff, or possibly House Elf."

  Harry grinned sheepishly. "Professor McGonagall says that I'm the most Ravenclaw person she's ever seen or heard tell of in legend, so much so that Rowena herself would tell me to get out more, whatever that means, and that I'll undoubtedly end up in Ravenclaw House if the hat isn't screaming too loudly for the rest of us to make out any words, end quote."

  "Wow," said Draco Malfoy, sounding slightly impressed. The boy gave a sort of wistful sigh. "Your flattery was great, or I thought so, anyway - you'd do well in Slytherin House, too. Usually it's only my father who gets that sort of grovelling. I'm hoping the other Slytherins will suck up to me now I'm at Hogwarts... I guess this is a good sign, then."

  Harry coughed. "Actually, sorry, I've got no idea who you are really."

  "Oh come on!" the boy said with fierce disappointment. "Why'd you go and do that, then?" Draco's eyes widened with sudden suspicion. "And how do you not know about the Malfoys? And what are those clothes you're wea
ring? Are your parents Muggles?"

  "Two of my parents are dead," Harry said. His heart twinged. When he put it that way - "My other two parents are Muggles, and they're the ones that raised me."

  "What?" said Draco. "Who are you?"

  "Harry Potter, pleased to meet you."

  "Harry Potter?" gasped Draco. "The Harry -" and the boy cut off abruptly.

  There was a brief silence.

  Then, with bright enthusiasm, "Harry Potter? The Harry Potter? Gosh, I've always wanted to meet you!"

  Draco's attendant emitted a sound like she was strangling but kept on with her work, lifting Draco's arms to carefully remove the chequered robe.

  "Shut up," Harry suggested.

  "Can I have your autograph? No, wait, I want a picture with you first!"

  "Shutupshutupshutup."

  "I'm just so delighted to meet you!"

  "Burst into flames and die."

  "But you're Harry Potter, the glorious saviour of the wizarding world! Everyone's hero, Harry Potter! I've always wanted to be just like you when I grow up so I can -"

  Draco cut off the words in mid-sentence, his face freezing in absolute horror.

  Tall, white-haired, coldly elegant in black robes of the finest quality. One hand gripping a silver-handled cane which took on the character of a deadly weapon just by being in that hand. His eyes regarded the room with the dispassionate quality of an executioner, a man to whom killing was not painful, or even deliciously forbidden, but just a routine activity like breathing.

  That was the man who had, just that moment, strolled in through the open door.

  "Draco," said the man, low and very angry, "what are you saying?"

  In one split second of sympathetic panic, Harry formulated a rescue plan.

  "Lucius Malfoy!" gasped Harry Potter. "The Lucius Malfoy?"

  One of Malkin's assistants had to turn away and face the wall.

  Coolly murderous eyes regarded him. "Harry Potter."

  "I am so, so honoured to meet you!"

  The dark eyes widened, shocked surprise replacing deadly threat.

  "Your son has been telling me all about you," Harry gushed on, hardly even knowing what was coming out of his mouth but just talking as fast as possible. "But of course I knew about you all before then, everyone knows about you, the great Lucius Malfoy! The most honoured laureate of all the House of Slytherin, I've been thinking about trying to get into Slytherin House myself just because I heard you were in it as a child -"

  "What are you saying, Mr. Potter?" came a near-scream from outside the shop, and Professor McGonagall burst in a second later.

  There was such pure horror on her face that Harry's mouth opened automatically, and then blocked on nothing-to-say.

  "Professor McGonagall!" cried Draco. "Is it really you? I've heard so much about you from my father, I've been thinking of trying to get Sorted into Gryffindor so I can -"

  "What?" bellowed Lucius Malfoy and Professor McGonagall in perfect unison, standing side-by-side. Their heads swivelled to look at each other in duplicate motions, and then the two recoiled from one another as though performing a synchronised dance.

  There was a sudden flurry of action as Lucius seized Draco and dragged him out of the shop.

  And then there was silence.

  In Professor McGonagall's left hand lay a small drinking-glass, tilted over to one side in the forgotten rush, now slowly dripping drops of alcohol into the tiny puddle of red wine that had appeared on the floor.

  Professor McGonagall strode forward into the shop until she was opposite Madam Malkin.

  "Madam Malkin," said Professor McGonagall, her voice calm. "What has been happening here?"

  Madam Malkin looked back silently for four seconds, and then cracked up. She fell against the wall, wheezing out laughter, and that set off both of her assistants, one of whom fell to her hands and knees on the floor, giggling hysterically.

  Professor McGonagall slowly turned to look at Harry, her expression chilly. "I leave you alone for six minutes. Six minutes, Mr. Potter, by the very clock."

  "I was only joking around," Harry protested, as the sounds of hysterical laughter went on nearby.

  "Draco Malfoy said in front of his father that he wanted to be sorted into Gryffindor! Joking around isn't enough to do that!" Professor McGonagall paused, visibly taking breaths. "What part of 'get fitted for robes' sounded to you like please cast a Confundus Charm on the entire universe!"

  "He was in a situational context where those actions made internal sense -"

  "No. Don't explain. I don't want to know what happened in here, ever. Whatever dark power inhabits you, it is contagious, and I don't want to end up like poor Draco Malfoy, poor Madam Malkin and her two poor assistants."

  Harry sighed. It was clear that Professor McGonagall wasn't in a mood to listen to reasonable explanations. He looked at Madam Malkin, who was still wheezing against the wall, and Malkin's two assistants, who had now both fallen to their knees, and finally down at his own tape-measure-draped body.

  "I'm not quite done being fitted for clothes," Harry said kindly. "Why don't you go back and have another drink?"

  Chapter 6: The Planning Fallacy

  Blah blah disclaimer blah blah Rowling blah blah ownership.

  A/N: The "Aftermath" section of this chapter is part of the story, not omake.

  You think your day was surreal? Try mine.

  Some children would have waited until after their first trip to Diagon Alley.

  "Bag of element 79," Harry said, and withdrew his hand, empty, from the mokeskin pouch.

  Most children would have at least waited to get their wands first.

  "Bag of okane," said Harry. The heavy bag of gold popped up into his hand.

  Harry withdrew the bag, then plunged it again into the mokeskin pouch. He took out his hand, put it back in, and said, "Bag of tokens of economic exchange." That time his hand came out empty.

  "Give me back the bag that I just put in." Out came the bag of gold once more.

  Harry James Potter-Evans-Verres had gotten his hands on at least one magical item. Why wait?

  "Professor McGonagall," Harry said to the bemused witch strolling beside him, "can you give me two words, one word for gold, and one word for something else that isn't money, in a language that I wouldn't know? But don't tell me which is which."

  "Ahava and zahav," said Professor McGonagall. "That's Hebrew, and the other word means love."

  "Thank you, Professor. Bag of ahava." Empty.

  "Bag of zahav." And it popped up into his hand.

  "Zahav is gold?" Harry questioned, and Professor McGonagall nodded.

  Harry thought over his collected experimental data. It was only the most crude and preliminary sort of effort, but it was enough to support at least one conclusion:

  "Aaaaaaarrrgh this doesn't make any sense!"

  The witch beside him lifted a lofty eyebrow. "Problems, Mr. Potter?"

  "I just falsified every single hypothesis I had! How can it know that 'bag of 115 Galleons' is okay but not 'bag of 90 plus 25 Galleons'? It can count but it can't add? It can understand nouns, but not some noun phrases that mean the same thing? The person who made this probably didn't speak Japanese and I don't speak any Hebrew, so it's not using their knowledge, and it's not using my knowledge -" Harry waved a hand helplessly. "The rules seem sorta consistent but they don't mean anything! I'm not even going to ask how a pouch ends up with voice recognition and natural language understanding when the best Artificial Intelligence programmers can't get the fastest supercomputers to do it after thirty-five years of hard work," Harry gasped for breath, "but what is going on?"

  "Magic," said Professor McGonagall.

  "That's just a word! Even after you tell me that, I can't make any new predictions! It's exactly like saying 'phlogiston' or 'elan vital' or 'emergence' or 'complexity'!"

  The black-robed witch laughed aloud. "But it is magic, Mr. Potter."

  Harry slumped over
a little. "With respect, Professor McGonagall, I'm not quite sure you understand what I'm trying to do here."

  "With respect, Mr. Potter, I'm quite sure I don't. Unless - this is just a guess, mind - you're trying to take over the world?"

  "No! I mean yes - well, no!"

  "I think I should perhaps be alarmed that you have trouble answering the question."

  Harry glumly considered the Dartmouth Conference on Artificial Intelligence in 1956. It had been the first conference ever on the topic, the one that had coined the phrase "Artificial Intelligence". They had identified key problems such as making computers understand language, learn, and improve themselves. They had suggested, in perfect seriousness, that significant advances on these problems might be made by ten scientists working together for two months.

  No. Chin up. You're just starting on the problem of unravelling all the secrets of magic. You don't actually know whether it's going to be too difficult to do in two months.

  "And you really haven't heard of other wizards asking these sorts of questions or doing this sort of scientific experimenting?" Harry asked again. It just seemed so obvious to him.

  Then again, it'd taken more than two hundred years after the invention of the scientific method before any Muggle scientists had thought to systematically investigate which sentences a human four-year-old could or couldn't understand. The developmental psychology of linguistics could've been discovered in the eighteenth century, in principle, but no one had even thought to look until the twentieth. So you couldn't really blame the much smaller wizarding world for not investigating the Retrieval Charm.

  Professor McGonagall pursed her lips, then shrugged. "I'm still not sure what you mean by 'scientific experimenting', Mr. Potter. As I said, I've seen Muggleborn students try to get Muggle science to work inside Hogwarts, and people invent new Charms and Potions every year."

  Harry shook his head. "Technology isn't the same thing as science at all. And trying lots of different ways to do something isn't the same as experimenting to figure out the rules." There were plenty of people who'd tried to invent flying machines by trying out lots of things-with-wings, but only the Wright Brothers had built a wind tunnel to measure lift... "Um, how many Muggle-raised children do you get at Hogwarts every year?"