Harry Potter and the Methods of Rationality

by Eliezer Yudkowsky

  The direction formerly known as 'up' was getting steadily brighter, as they came closer to the surface and Sunshine.

  "Wands out," said General Chaos.

  Neville's squad drew their wands, pointing them straight ahead toward the enemy, as their heads scanned around more rapidly. If there were Sunny traitors, the time was approaching for them to strike.

  The other shoal of fish, Dragon Army, was doing the same thing.

  "Now!" shouted the distant voice of the Dragon General.

  "Now!" shouted General Chaos.

  "For Sunshine!" shouted all the soldiers in both armies, and charged downward.

  "What?" said Minerva involuntarily as she watched the screens from next to the lake, a cry echoed in many other places; all of Hogwarts was watching this battle as they had watched the first.

  Professor Quirrell was laughing dryly. "I warned you, Headmaster. It is impossible to have rules without Mr. Potter exploiting them."

  For long precious seconds, as the forty-seven soldiers charged her own seventeen, Hermione's mind went blank.

  Why...

  Then it all snapped into place.

  Every time a soldier originally from Sunshine got shot by someone crying the name of Sunshine, she would lose a Quirrell point. When two Sunshine Soldiers were shot by either army, both enemy armies would be two points closer to overtaking her, it was the same gain only shared. And if anyone shot another soldier not in the name of Sunshine, that gong wouldn't get lost in the confusion...

  Hermione was suddenly very glad that Zabini hadn't gone with the obvious plan of starting trouble between the other two armies while they attacked Sunshine.

  It was still disheartening, though, that sense of your chances closing down, of hope being taken away.

  Most of Hermione's soldiers were still looking confused, but some had expressions of dawning horror as they got it.

  "It's all right," Susan Bones said firmly. Heads turned to look at the Sunshine Captain. "Our job is the same, to take as many of them with us as we can. And remember, Zabini took away all the spies! We don't have to stay on the lookout like they do!" The girl was smiling defiantly, provoking answering smiles from many of the other soldiers, even from Hermione herself. "It can be like it was in November. We just have to keep our heads high, fight our best, and trust each other -"

  Daphne shot her.

  "Blood for the blood god!" shrieked Neville of Chaos, though since he was underwater it came out more like 'Blubbled for the blubbled glub!'

  Captain Weasley spun and raised his wand toward Neville and fired. But Neville was swimming downward toward him, wand pointed straight ahead, and that meant the Simple Shield could shelter Neville's entire profile; if anyone shot him now, it wasn't going to be Sunny Ron.

  A grimly determined look came over Captain Weasley's face, and he arrowed straight up toward Neville, mouthing the word Contego, though the shield wasn't visible in the water.

  The two enemy champions shot toward each other like arrows released from bows, each aimed to split the other down the middle. They had dueled many times before, but this time would pay for all.

  (Far away by the lakeside, a hundred breaths were held.)

  "Rainbows and unicorns!" roared the Sunshine Captain.

  "The Black Goat with a thousand young!"

  "Do your homework!"

  Closer and yet closer, the two champions charged, neither willing to swerve, the first person to turn would present a vulnerable broadside and get shot, though if neither lost their nerve they would crash right into each other...

  Falling straight down as the enemy rose straight up to meet him, hammer descending to meet anvil in a path neither was willing to leave...

  "Special attack, Chaotic Twist!"

  Neville saw the look of horror on Captain Weasley's face as the Hover Charm caught him. They'd tested it before the battle had started; and just as Harry had suspected, Wingardium Leviosa became a whole new sort of weapon once everyone was swimming underwater.

  "Curse you, Longbottom!" shrieked Ron Weasley, "Can't you ever fight without your dumb special attacks -"

  and by that time the Sunshine Captain had been spun around sideways and Neville shot him in the leg.

  "I don't fight fair," said Neville to the sleeping form, "I fight like Harry Potter."

  Granger: 237 / Malfoy: 217 / Potter: 220

  It still hurt every time he had to shoot Hermione. Harry could hardly stand to look at the expression of peace that had come over her sleeping face, arms now drifting aimlessly as the curves of sunlight moved over her camouflage uniform and the cloud of her chestnut hair.

  And if Harry had tried to duck out of being the one to shoot her... not only would Draco have known what it meant, Hermione would have been offended.

  She's not dead, Harry said to his brain as his kicking feet pushed him away, she's just resting. IDIOT.

  Are you sure? said his brain. What if she's an ex-Hermione? Could we go back and check?

  Harry glanced back briefly.

  See, she's fine, there are bubbles coming out of her mouth.

  Could've been her last breath escaping.

  Oh be quiet. Why are you being so paranoid-protective, anyway?

  Er, first real friend we've ever had in our whole life? Hey, remember what happened to our pet rock?

  Would you SHUT UP about that worthless lump of rubble, it wasn't even alive let alone sentient, that is like the most pathetic childhood trauma ever -

  The two armies swiftly separated, becoming two shoals of fish once more.

  General Granger had gone down seventeen points, and taken three Chaotics and two Dragons with her; and one Chaotic and two Dragons had been shot as traitors. So she'd lost net seven points, Harry had lost one, Draco had lost two; that put Sunshine twenty points up on Dragon, and seventeen points up on Chaos. Chaos could still win easily if they exterminated all twenty remaining Dragons. The wild card, of course, being those seven remaining Sunshine Soldiers...

  ...if you could call them that.

  The two shoals swam uneasily next to each other, the soldiers in each army awaiting an order to call out their true allegiances, and attack...

  "Everyone who got them," Harry said loudly, "remember Special Orders One through Three. And don't forget it's Merlin Says on Three. Do not acknowledge."

  The trustworthy two-thirds of the army did not nod, and the other third just looked puzzled.

  Special Order One: Don't bother trying to call out any codewords in this battle, don't expend effort on any plot not specially approved by the commander; just swim, shield, and fire.

  Hermione and Draco had both been fighting their soldiers, trying to get them to stop plotting on their own all through December. Harry had egged his soldiers on and supported their plotting through the last two battles... while also telling them that at some future point he might ask them to put a plot or two on hold, to which they'd all readily agreed. So now, in this critical battle, they were happy to obey.

  Neither Hermione or Draco could have given that order successfully, Harry was certain. It was the difference between your soldiers seeing you as an ally in their plotting, and seeing you as a spoilsport old fuddy-duddy who didn't want them to have any fun. Imposition of order equaled escalation of chaos, and it also worked in reverse...

  "There they are!" shouted someone, and pointed.

  From the depths of the lake arose the forgotten ones, the ones who'd forsaken the last battle, the seven missing Sunshine Soldiers, glowing with the bright aura of cowards, now fading as they returned to battle.

  The two shoals of fish wavered, pointing wands uneasily.

  "Hold your fire!" shouted Harry, and a similar cry came from General Malfoy.

  There was a moment of held breath.

  Then the seven Sunshine Soldiers swam up to join Dragon Army.

  There was a triumphant cheer from Dragon Army.

  There were cries of dismay from a third of the Chaos Legion.

&n
bsp; Some of the other two-thirds smiled, though they shouldn't have.

  Harry wasn't smiling.

  Oh, this is so completely not going to work...

  But Harry hadn't been able to think of anything better.

  "Special Orders Two and Three still apply!" shouted Harry. "Fight!"

  "For the Chaos Legion!" roared twenty Chaotic Legionnaires.

  "For Dragon Army!" roared twenty Dragon Warriors and seven Sunshine Soldiers.

  And the Chaotics dived straight downward, as all the traitors got ready to strike.

  Granger: 237 / Malfoy: 220 / Potter: 226

  Draco's head darted around frantically, trying to weigh up what was happening; somehow, despite his greater forces, he'd lost the initiative. Four small Chaotic forces were being pursued by four larger Dragon forces, but because Draco's forces were the ones trying to force an engagement, it meant that they had to follow where Chaos ran, and somehow that was producing concentrations of Chaotic force that would fire into the exposed sides of Dragon -

  It was happening again!

  "Prismatis!" shouted Draco, raising his wand, and that shield you could see even through the water, a sparkling multicolored flat wall wide enough to shield Draco and the five other Dragons with him from the Chaotic force that had just started firing on them as they swam past, and that let the other five Dragons turn their attentions back to the Chaotic force they'd been chasing -

  There was a tense moment as sleep spell after sleep spell crashed into Draco's Prismatic Wall, and Draco was hoping to Merlin that none of those four Chaotics had learned the Breaking Drill Hex -

  Then there was the bell of a Dragon victory, and the Chaotic force spun head-for-foot and began swimming away; and Draco, his hands now shaking slightly, dropped the Prismatic Wall and lowered his wand.

  Fighting in water was more exhausting even than fighting on broomsticks.

  "Do not pursue!" Draco cried to his soldiers as they started to follow, then, "Sonorus! REFORM ON ME!"

  The Dragon forces started converging on Draco, and the Chaotic forces spun around and began pursuing the Dragons on the instant - Draco swore out loud as he heard the bell of a Chaotic victory, someone hadn't gotten their Simple Shield oriented right - and then the Dragon forces were in supporting range of each other and the Chaotics were moving back into the murky distance.

  Somehow, despite their numerical superiority, the Dragons had scored three times against the Chaotics and the Chaotics had scored four times back, and he'd heard one Dragon spy get executed. Either Harry Potter had thought of a lot of very good ideas very fast, or for some unimaginable reason he'd already spent a lot of time working out how to fight underwater. This wasn't working, and Draco needed to rethink things.

  It looked like everyone was having trouble aiming while swimming, too, the battle might last long enough that time would be called... the distant underwater moon was only half full now, that wasn't good... he had to rethink things fast...

  "What is it?" said Padma Patil, as she and her force swam over toward Draco.

  Padma was his second-in-command; she was clever and powerful, and better yet, she hated Granger and saw Harry as a rival, which made her trustworthy. Working with Padma was making him realize the truth of the old adage that Ravenclaw was sister to Slytherin; Draco had been surprised when his father had told him it was an acceptable House for his future wife, but now he saw the sense of it.

  "Wait until we're all here," Draco said. The truth was, he needed to catch his breath. That was the trouble with being the general and the most powerful wizard, you had to keep using magic.

  Zabini came in next, commanding a force of two Sunnies and four Dragons, one of whom was Gregory keeping an eye on Zabini. Draco didn't trust Zabini. And neither Draco nor Zabini trusted the Sunnies enough to make them a majority of any unit; they were supposed to be loyal either to Draco directly, or to Granger who'd been fooled by the promise that the Dragons would be betrayed in the end after both forces had been depleted, just as Harry's more trusted Chaotics should've been fooled into not shooting at the Sunnies by the promise of their firing fake Sleep Hexes and switching to support Chaos later; but it was possible some of the Sunnies were loyal to Chaos and weren't firing real Sleep Hexes and that was why Dragon wasn't winning the way their numerical advantage should've let them win...

  The next unit that approached was depleted, three soldiers holding wands on two other soldiers, who were swimming with empty hands.

  Draco gritted his teeth. More traitor problems. He needed to talk to Professor Quirrell about having some way to punish traitors at least, conditions like these were unrealistic, in real life you tortured your traitors to death.

  "General Malfoy!" shouted the commander of the problem unit as it swam up, a Ravenclaw boy named Terry. "We don't know what to do - Cesi shot Bogdan, but Cesi says Kellah told him that Bogdan shot Specter -"

  "I didn't!" said Kellah.

  "Yes you did!" shrieked Cesi. "General Malfoy, she's the spy, I should've rea-"

  "Somnium," said Draco.

  There was the triple bell of a one-point loss from Dragon, and then Kellah's limp body began to float away in the water.

  Draco had heard the word 'recursion' by this point, and he knew a Harry Potter plot when he saw one.

  (Unfortunately Draco had not heard of autoimmune disorders, and the thought did not readily occur to him that a clever virus would begin its attack by creating symptoms of an autoimmune disorder so as to get the body to distrust its own immune system...)

  "General order!" said Draco, raising his voice. "Nobody gets to shoot spies except myself, Gregory, Padma, and Terry. If anyone sees anything suspicious they come to one of us."

  And then -

  There was the bell of Sunshine scoring two points.

  "What?" said Draco and Zabini around the same time; their heads swiveled around. No one seemed to have gotten hit, and all the Sunshine soldiers were present and accounted for. (Except Parvati, who had been shot by some still-unknown traitor in Padma's squad; and of course Padma had shot Parvati again in case she was faking, so it wasn't her...)

  "A Sunny traitor in Chaos?" said Zabini, sounding puzzled. "But all the ones I knew about were supposed to strike during Chaos's attack on Sunshine -"

  "No!" said Padma in a tone of sudden realization. "That was Chaos executing a spy!"

  "What?" said Zabini. "But why -"

  And Draco got it. Damn it! "Because Potter thinks he's safe for how much he beats Sunshine, but not for how much he beats us! So he doesn't want to lose a single point when he executes a traitor! General order! If you have to execute a traitor, call Sunshine first! And don't forget to switch back to Dragon afterward -"

  Granger: 253 / Malfoy: 252 / Potter: 252

  Longbottom's body drifted chaotically through the water, arms and legs disarrayed. After Draco had finally got a hit in they'd all shot him again just to be sure.

  Nearby was Harry Potter, now protected by a Prismatic Sphere, looking at them all grimly as the last sliver of crescent moon slowly diminished, somewhere far away. If Longbottom had managed to shoot one more soldier (Draco knew Harry was thinking), if the two Chaotics had managed to hold out just a little longer, they might have won...

  After Draco had reformed his forces and struck out again, the ensuing battle and execution of spies in Sunshine's name had left Sunshine exactly one point ahead of Dragon and Chaos both. Once Harry had started doing it, Draco had been left with no choice but to follow suit.

  But now they had General Chaos outnumbered three to one, the survivors of Dragon Army and the last remaining Sunny traitor: Draco, and Padma, and Zabini.

  And Draco, who was no fool, had ordered Padma to take Zabini's wand after Longbottom had shot Gregory and fallen in turn to Draco. The boy had given him an insulted look, told Draco that he owed him for this, and handed it over.

  That left Draco and Padma to take down General Chaos.

  "I don't suppose you'd like to surrende
r?" said Draco, smiling as evilly as any smile he'd ever directed at Harry Potter.

  "Sleep before surrender!" shouted General Chaos.

  "Just so you know," said Draco, "Zabini doesn't actually have an older sister for you to rescue from Gryffindor bullies. But Zabini does have a mother who doesn't approve of Muggleborns like Granger, and I wrote her a few notes, and offered Zabini a few favors - nothing involving my father, just things I can do in school. And by the way, Zabini's mother doesn't approve of the Boy-Who-Lived, either. Just in case you still thought Zabini was really on your side."

  Harry's face grew even grimmer.

  Draco raised his wand, and began breathing rhythmically, building up strength for a Breaking Drill Hex. Granger's Prismatic Sphere was almost as strong as Draco's now, and Harry's wasn't much weaker, where did those two find time?

  "Lagann!" spoke Draco, putting everything he had into it, and the green spiral blazed out and Harry's shield shattered, and at almost the same moment -

  "Somnium!" said Padma.

  Granger: 253 / Malfoy: 252 / Potter: 254

  Harry let out a long breath of relief, and not just because he didn't have to hold the Prismatic Sphere any more. His hand was shaking as he lowered his wand.

  "You know," said Harry, "I was pretty worried there for a moment."

  Special Order Two: If a Sunny traitor doesn't seem to be really shooting at you, fake being hit occasionally. Prefer targeting Dragons to Sunnies but go ahead and shoot Sunnies if you can't shoot Dragons.

  Special Order Three: Merlin says do not shoot at Blaise Zabini or either Patil twin.

  With a wide grin, Parvati Patil stripped the Transfigured patch off her uniform's insignia, and let it float away in the water.

  "Gryffindors for Chaos," she said, and handed Zabini his wand back.

  "Thank you very much," Harry said, and bowed sweepingly to the Gryffindor girl. "And thank you as well," bowing to Zabini. "You know, when you came to me with that plan, I wondered if you were brilliant or crazy, and I've decided that you're both. And by the way," Harry said, now turning as though to address Draco's body, "Zabini does have a cousin -"