Harry Potter and the Methods of Rationality

by Eliezer Yudkowsky

"In character?" said the old wizard.

  "I mean," said Harry, "it's entirely consistent with the way Professor Quirrell usually acts..." Harry trailed off. Why had he put it that way?

  The Headmaster nodded. "So you have the same sense I do; that it is an excuse. A very reasonable excuse, to be sure; more so than you may realize. Often, wizards seemingly unable to cast a Patronus Charm will succeed in the presence of an actual Dementor, going from not a single flicker of light to a full corporeal Patronus. Why this should be, no one knows; but it is so."

  Harry frowned. "Then I really don't see why you're suspicious -"

  The Headmaster spread his hands as though in helplessness. "Harry, the Defense Professor has asked me to pass the darkest of all creatures through the gates of Hogwarts. I must be suspicious." The Headmaster sighed. "And yet the Dementor will be guarded, warded, in a mighty cage, I will be there myself to watch it at all times - I cannot think of what ill could be done. But perhaps I am merely unable to see it. And so I am asking you."

  Harry stared at the Headmaster with his mouth open. He was so shocked he couldn't even feel flattered.

  "Me?" said Harry.

  "Yes," said Dumbledore, smiling slightly. "I try my best to anticipate my foes, to encompass their wicked minds and predict their evil thoughts. But I would never have imagined sharpening a Hufflepuff's bones into weapons."

  Was Harry ever going to live that down?

  "Headmaster," Harry said wearily, "I know it doesn't sound good, but in all seriousness: I'm not evil, I'm just very creative -"

  "I did not say that you were evil," Dumbledore said seriously. "There are those who say that to comprehend evil is to become evil; but they are merely pretending to be wise. Rather it is evil which does not know love, and dares not imagine love, and cannot ever understand love without ceasing to be evil. And I suspect that you can imagine your way into the minds of Dark Wizards better than I ever could, while still knowing love yourself. So, Harry." The Headmaster's eyes were intent. "If you stood in Professor Quirrell's shoes, what misdeeds could you accomplish after you tricked me into allowing a Dementor onto the grounds of Hogwarts?"

  "Hold on," said Harry, and in something of a daze trudged over to the chair in front of the Headmaster's desk, and sat down. It was a large and comfortable chair this time, not a wooden stool, and Harry could feel himself enveloped as he sank into it.

  Dumbledore was asking him to outwit Professor Quirrell.

  Point one: Harry was rather fonder of Professor Quirrell than of Dumbledore.

  Point two: The hypothesis was that the Defense Professor was planning to do something evil, and in that subjunctive case, Harry ought to be helping the Headmaster prevent it.

  Point three...

  "Headmaster," Harry said, "if Professor Quirrell is up to something, I'm not sure I can outwit him. He's got a lot more experience than I do."

  The old wizard shook his head, somehow managing to appear very solemn despite his smile. "You underestimate yourself."

  That was the first time anyone had ever said that to Harry.

  "I remember," the old wizard continued, "a young man in this very office, cold and controlled as he faced down the Head of House Slytherin, blackmailing his own Headmaster to protect his classmates. And I believe that young man is more cunning than Professor Quirrell, more cunning than Lucius Malfoy, that he will grow to be the equal of Voldemort himself. It is he who I wish to consult."

  Harry suppressed the chill that went through him at the name, frowned thoughtfully at the Headmaster.

  How much does he know...?

  The Headmaster had seen Harry in the grip of his mysterious dark side, as deep as Harry had ever sunk into it. Harry still remembered what it had been like to watch, invisibly Time-Turned, as his past self faced down the older Slytherins; the boy with the scar on his forehead who didn't act like the others. Of course the Headmaster would have noticed something odd about the boy in his office...

  And Dumbledore had concluded that his pet hero had cunning to match his destined foe, the Dark Lord.

  Which wasn't asking for very much, considering that the Dark Lord had put a clearly visible Dark Mark on all of his servants' left arms, and that he'd slaughtered the entire monastery that taught the martial art he'd wanted to learn.

  Enough cunning to match Professor Quirrell would be a whole different order of problem.

  But it was also clear that the Headmaster wouldn't be satisfied until Harry went all cold and darkish, and came up with some sort of answer that sounded impressively cunning... which had better not actually get in the way of Professor Quirrell's teaching Defense...

  And of course Harry would go over to his dark side and think it through from that direction, just to be honest, and just in case.

  "Tell me," Harry said, "everything about how the Dementor is to be brought in, and how it is to be guarded."

  Dumbledore's eyebrows rose for a moment, and then the old wizard began to speak.

  The Dementor would be transported to the grounds of Hogwarts by an Auror trio, all three personally known to the Headmaster, and all three able to cast a corporeal Patronus Charm. They would be met at the edge of the grounds by Dumbledore, who would pass the Dementor through the Hogwarts wards -

  Harry asked if the pass was permanent or temporary - whether someone could just bring in the same Dementor again the next day.

  The pass was temporary (replied the Headmaster with an approving nod), and the explanation went on: The Dementor would be in a cage of solid titanium bars, not Transfigured but true-forged; in time a Dementor's presence would corrode that metal to dust, but not in a single day.

  Students awaiting their turn would stay well back of the Dementor, behind two corporeal Patronuses maintained by two of the three Aurors at any given time. Dumbledore would wait by the Dementor's cage with his Patronus. A single student would approach the Dementor; and Dumbledore would dispel his Patronus; and the student would attempt to cast their own Patronus Charm; and if they failed, Dumbledore would restore his Patronus before the student could suffer any permanent damage. Past dueling champion Professor Flitwick would also be present while there were students near, just to add safety margin.

  "Why just you waiting by the Dementor?" said Harry. "I mean, shouldn't it be you plus an Auror -"

  The Headmaster shook his head. "They could not withstand the repeated exposure to the Dementor, each time I dispel my Patronus."

  And if Dumbledore's Patronus did fail for some reason, while one of the students was still near the Dementor, the third Auror would cast another corporeal Patronus and send it to shield the student...

  Harry poked and prodded, but he couldn't see a flaw in the security.

  So Harry took a deep breath, sank further into the chair, closed his eyes, and remembered:

  "And that will be... five points? No, let us make it an even ten points from Ravenclaw for backchat."

  The cold came more slowly now, more reluctantly, Harry hadn't been calling much on his dark side lately...

  Harry had to run through that entire session in Potions in his mind, before his blood chilled into something approaching deadly crystalline clarity.

  And then he thought of the Dementor.

  And it was obvious.

  "The Dementor is a distraction," Harry said. The coldness clear in his voice, since that was what Dumbledore wanted and expected. "A large, salient threat, but in the end straightforward, and easy to defend against. So while all your attention is focused on the Dementor, the real plot will be happening elsewhere."

  Dumbledore stared at Harry for a moment, and then gave a slow nod. "Yes..." said the Headmaster. "And I do believe I know what it might be a distraction from, if Professor Quirrell means ill... thank you, Harry."

  The Headmaster was still staring at Harry, a strange look in those ancient eyes.

  "What?" said Harry with a tinge of annoyance, the cold still lingering in his blood.

  "I have another question for that yo
ung man," said the Headmaster. "It is something I have long wondered to myself, yet been unable to comprehend. Why?" There was a tinge of pain in his voice. "Why would anyone deliberately make himself a monster? Why do evil for the sake of evil? Why Voldemort?"

  Whirr, bzzzt, tick; ding, puff, splat...

  Harry stared at the Headmaster in surprise.

  "How would I know?" said Harry. "Am I supposed to magically understand the Dark Lord because I'm the hero, or something?"

  "Yes!" said Dumbledore. "My own great foe was Grindelwald, and him I understood very well indeed. Grindelwald was my dark mirror, the man I could so easily have been, had I given in to the temptation to believe that I was a good person, and therefore always in the right. For the greater good, that was his slogan; and he truly believed it himself, even as he tore at all Europe like a wounded animal. And him, I defeated in the end. But then after him came Voldemort, to destroy everything I had protected in Britain." The hurt was plain now in Dumbledore's voice, exposed upon his face. "He committed acts worse by far than Grindelwald's worst, horror for the sake of horror. I sacrificed everything only to hold him back, and I still don't understand why! Why, Harry? Why did he do it? He was never my destined foe, but yours, so if you have any guesses at all, Harry, please tell me! Why?"

  Harry stared down at his hands. The truth was that Harry hadn't read up on the Dark Lord yet, and right now he hadn't the tiniest clue. And somehow that didn't seem like an answer the Headmaster wanted to hear. "Too many Dark rituals, maybe? In the beginning he thought he'd do just one, but it sacrificed part of his good side, and that made him less reluctant to perform other Dark rituals, so he did more and more rituals in a positive feedback cycle until he ended up as a tremendously powerful monster -"

  "No!" Now the Headmaster's voice was agonized. "I can't believe that, Harry! There has to be something more to it than just that!"

  Why should there be? thought Harry, but he didn't say it, because it was clear that the Headmaster thought the universe was a story and had a plot, and that huge tragedies weren't allowed to happen except for equally huge, significant reasons. "I'm sorry, Headmaster. The Dark Lord doesn't seem like much of a dark mirror to me, not at all. There isn't anything I find even the tiniest bit tempting about nailing the skins of Yermy Wibble's family to a newsroom wall."

  "Have you no wisdom to share?" said Dumbledore. There was pleading in the old wizard's voice, almost begging.

  Evil happens, thought Harry, it doesn't mean anything or teach us anything, except to not be evil? The Dark Lord was probably just a selfish bastard who didn't care who he hurt, or an idiot who made stupidly avoidable mistakes that snowballed. There is no destiny behind the ills of this world; if Hitler had been allowed into architecture school like he wanted, the whole history of Europe would have been different; if we lived in the sort of universe where horrible things were only allowed to happen for good reasons, they just wouldn't happen in the first place.

  And none of that, obviously, was what the Headmaster wanted to hear.

  The old wizard was still looking at Harry from over a fiddly thing like a frozen puff of smoke, a painful desperation in those ancient, waiting eyes.

  Well, sounding wise wasn't difficult. It was a lot easier than being intelligent, actually, since you didn't have to say anything surprising or come up with any new insights. You just let your brain's pattern-matching software complete the cliche, using whatever Deep Wisdom you'd stored previously.

  "Headmaster," Harry said solemnly, "I would rather not define myself by my enemies."

  Somehow, even in the midst of all the whirring and ticking, there was a kind of silence.

  That had come out a bit more Deeply Wise than Harry had intended.

  "You may be very wise, Harry..." the Headmaster said slowly. "I do wish... that I could have been defined by my friends." The pain in his voice had grown deeper.

  Harry's mind searched hastily for something else Deeply Wise to say that would soften the unintended force of the blow -

  "Or perhaps," Harry said more softly, "it is the foe that makes the Gryffindor, as it is the friend that makes the Hufflepuff, and the ambition that makes the Slytherin. I do know that it is always, in every generation, the puzzle that makes the scientist."

  "It is a dreadful fate to which you condemn my House, Harry," said the Headmaster. The pain was still in his voice. "For now that you remark on it, I do think that I was very much made by my enemies."

  Harry stared at his own hands, where they lay in his lap. Maybe he should just shut up while he was ahead.

  "But you have answered my question," said Dumbledore more softly, as though to himself. "I should have realized that would be a Slytherin's key. For his ambition, all for the sake of his ambition; and that I know, though not why..." For a time Dumbledore stared off into nothingness; then he straightened, and his eyes seemed to focus on Harry again.

  "And you, Harry," said the Headmaster, "you name yourself a scientist?" His voice was laced with surprise and mild disapproval.

  "You don't like science?" said Harry a little wearily. He'd hoped Dumbledore would be fonder of Muggle things.

  "I suppose it is useful to those without wands," said Dumbledore, frowning. "But it seems a strange thing by which to define yourself. Is science as important as love? As kindness? As friendship? Is it science that makes you fond of Minerva McGonagall? Is it science that makes you care for Hermione Granger? Will it be science to which you turn, when you try to kindle warmth in Draco Malfoy's heart?"

  You know, the sad thing is, you probably think you just uttered some kind of incredibly wise knockdown argument.

  Now, how to phrase the rejoinder in such fashion that it also sounded incredibly wise...

  "You are not Ravenclaw," Harry said with calm dignity, "and so it might not have occurred to you that to respect the truth, and seek it all the days of your life, could also be an act of grace."

  The Headmaster's eyebrows rose up. And then he sighed. "How did you become so wise, so young...?" The old wizard sounded sad, as he said it. "Perhaps it will prove valuable to you."

  Only for impressing ancient wizards who are overly impressed with themselves, thought Harry. He was actually a bit disappointed by Dumbledore's credulity; it wasn't that Harry had lied, but Dumbledore seemed far too impressed with Harry's ability to phrase things so that they sounded profound, instead of putting them into plain English like Richard Feynman had done with his wisdom...

  "Love is more important than wisdom," said Harry, just to test the limits of Dumbledore's tolerance for blindingly obvious cliches completed by sheer pattern matching without any sort of detailed analysis.

  The Headmaster nodded gravely, and said, "Indeed."

  Harry stood up out of the chair, and stretched his arms. Well, I'd better go off and love something, then, that's bound to help me defeat the Dark Lord. And next time you ask me for advice, I'll just give you a hug -

  "This day you have helped me much, Harry," said the Headmaster. "And so there is one last thing I would ask that young man."

  Great.

  "Tell me, Harry," said the Headmaster (and now his voice sounded simply puzzled, though there was still a hint of pain in his eyes), "why do Dark Wizards fear death so greatly?"

  "Er," said Harry, "sorry, I've got to back the Dark Wizards on that one."

  Whoosh, hiss, chime; glorp, pop, bubble -

  "What?" said Dumbledore.

  "Death is bad," said Harry, discarding wisdom for the sake of clear communication. "Very bad. Extremely bad. Being scared of death is like being scared of a great big monster with poisonous fangs. It actually makes a great deal of sense, and does not, in fact, indicate that you have a psychological problem."

  The Headmaster was staring at him as though he'd just turned into a cat.

  "Okay," said Harry, "let me put it this way. Do you want to die? Because if so, there's this Muggle thing called a suicide prevention hotline -"

  "When it is time," the old wiza
rd said quietly. "Not before. I would never seek to hasten the day, nor seek to refuse it when it comes."

  Harry was frowning sternly. "That doesn't sound like you have a very strong will to live, Headmaster!"

  "Harry..." The old wizard's voice was starting to sound a little helpless; and he had paced to a spot where his silver beard, unnoticed, had drifted into a crystalline glass goldfish bowl, and was slowly taking on a greenish tinge that crept up the hairs. "I think I may have not made myself clear. Dark Wizards are not eager to live. They fear death. They do not reach up toward the sun's light, but flee the coming of night into infinitely darker caverns of their own making, without moon or stars. It is not life they desire, but immortality; and they are so driven to grasp at it that they will sacrifice their very souls! Do you want to live forever, Harry?"

  "Yes, and so do you," said Harry. "I want to live one more day. Tomorrow I will still want to live one more day. Therefore I want to live forever, proof by induction on the positive integers. If you don't want to die, it means you want to live forever. If you don't want to live forever, it means you want to die. You've got to do one or the other... I'm not getting through here, am I."

  The two cultures stared at each other across a vast gap of incommensurability.

  "I have lived a hundred and ten years," the old wizard said quietly (taking his beard out of the bowl, and jiggling it to shake out the color). "I have seen and done a great many things, too many of which I wish I had never seen or done. And yet I do not regret being alive, for watching my students grow is a joy that has not begun to wear on me. But I would not wish to live so long that it does! What would you do with eternity, Harry?"

  Harry took a deep breath. "Meet all the interesting people in the world, read all the good books and then write something even better, celebrate my first grandchild's tenth birthday party on the Moon, celebrate my first great-great-great grandchild's hundredth birthday party around the Rings of Saturn, learn the deepest and final rules of Nature, understand the nature of consciousness, find out why anything exists in the first place, visit other stars, discover aliens, create aliens, rendezvous with everyone for a party on the other side of the Milky Way once we've explored the whole thing, meet up with everyone else who was born on Old Earth to watch the Sun finally go out, and I used to worry about finding a way to escape this universe before it ran out of negentropy but I'm a lot more hopeful now that I've discovered the so-called laws of physics are just optional guidelines."