Eliezer Yudkowsky - Harry Potter and the Methods of Rationality

Thirteen and a half inches, yew, with a core of phoenix feather. Harry had memorized the information when the wandmaker Olli-something had given it, because it had seemed like it might be Plot-Relevant. The event, and the thinking that had underlain it, both felt a lifetime distant.

The Defense Professor raised that wand, and traced in the air a flaming rune that was all jagged edges and malevolence; Harry took another instinctive step back. Then Professor Quirrell spoke. “Az-reth. Az-reth.

Az-reth.”

The flaming rune began pouring out fire that was… twisted, as though the jagged edges of the rune had become the nature of the fire itself. The fire was blazing crimson, shaded further red than blood, glowing as searingly intense as an arc-welder. That brilliance in that shade seemed wrong in its own right, like nothing shaded so far red should give off that much light; and the searing crimson was shot through with veins of black that seemed to suck the light from the fire. Within the blackened fire, outlined in the interplay of crimson and darkness, animal shapes twisted wildly from one predator to another, cobra to hyena to scorpion.

“Az-reth. Az-reth. Az-reth.” When Professor Quirrell had repeated the word six times, as much black-crimson fire had poured out as the volume of a small bush.

The cursed fire slowed in its changes as Professor Quirrell locked eyes upon it, taking on a single form, the form of a blackened blood-burning phoenix.

And something told Harry with a terrible certainty that if that black burning phoenix met Fawkes, the true phoenix would die and never be reborn.

Professor Quirrell made a single gesture with his wand, and the blackened fire went soaring across the room. It met the door and its keyhole, and with a single sweep of crimson-burning wings, most of the door and part of the archway was consumed. Then the tainted crimson blaze swept on.

Harry had only a glance through the hole to see huge statues just beginning to raise swords and clubs, when the blackened fire came among them, and they cracked and burned.

When it ended, the blackened-fire phoenix swept back in through the hole, and hovered above Professor Quirrell’s left shoulder, the sunintense crimson claws staying an inch from his robes.

“Go on ahead,” said Professor Quirrell. “It’s safe now.”

Harry walked forward, needing to invoke his dark side’s cognitive patterns in order to maintain calm enough to do it. Harry stepped over the glowing edges of the remaining part of the door, and gazed at a chessboard of ruined huge chess-pieces. The alternating tiles of black and white marble on the floor started five meters after the ruined doorway, and extended from wall to wall, but stopped five meters short of the next door on the opposite side of the room. The ceiling was significantly higher than any of the statues should have been able to reach.

“I would guess,” Harry said, and his dark side’s cognitive patterns kept his voice calm, “that the intended solution is to fly over the statues using the broomstick from the previous room, since it wasn’t actually needed to get the key?”

From behind, Professor Quirrell laughed, and it was Lord Voldemort’s laugh. “Proceed,” said a voice grown colder and higher. “Go to the next room. I wish to see what you will make of what is there.”

Arranged by Dumbledore for first-years, Harry reminded himself, it WILL be safe, and he walked across the ruined chessboard, laid his hand upon that door’s handle, and pushed it inward.

Half a second later, Harry slammed the door and leapt back.

It took Harry several seconds to master his breathing, and master himself. From behind the door came continued loud bellows, and great slams as of a rock club pounding the floor.

“I suppose,” Harry said in a voice grown cold as well, “that since Dumbledore would hardly put a real mountain troll in there, the next challenge is an illusion of my worst memories. Like a Dementor, with the memory projected into the outside world. Very amusing, Professor.”

Professor Quirrell advanced himself toward the door, and Harry stepped well aside. Besides the sense of doom that was now strong about the Professor, Harry’s dark side or just plain instinct was advising him not to get anywhere near that black-crimson fire hovering above Professor Quirrell’s shoulder.

Professor Quirrell swung open the door, and looked in. “Hm,” Professor Quirrell said. “Just the troll, as you say. Ah, well. I had hoped to learn something about you more interesting than that. What lies within is a

Kokorhekkus, also known as the common boggart.”

“A boggart? What does that—no, I suppose I know what it does.”

“A boggart,” Professor Quirrell said, and now his voice was again that of a Hogwarts Professor lecturing, “gravitates to dark enclosures that are rarely opened, such as a neglected cupboard in the attic. It seeks to be left alone, and it will manifest in whatever form it thinks will scare you away.”

“Scare me away?” Harry said. “I killed the troll.”

“You leapt backward out of the room without thinking. A boggart seeks out the instinctive flinch, not the reasoned threat. Else it would have selected something more believable. In any case, the standard counter-Charm for a boggart is, of course, Fiendfyre.” Professor Quirrell gestured, and the blackened fire leapt off his shoulder and poured through the doorway.

From within the room there was a single squeak, and then nothing.

They advanced into the boggart’s former room, Professor Quirrell going first this time. With the seeming mountain troll gone, the room was just another huge chamber lit by sconces of cold blue light.

Professor Quirrell’s gaze seemed distant, thoughtful. He crossed the room without waiting for Harry, and swung open the door on the opposite wall of his own accord.

Harry followed after, and not closely.

The next chamber contained a cauldron, a rack of bottled ingredients, chopping boards, stirring sticks, and the other apparatus of Potions. The light coming from the arched alcoves was white instead of blue, presumably because color vision was important to Potions-brewing. Professor Quirrell was already standing next to the brewing apparatus, scrutinizing a long parchment he had picked up. The door to the next chamber was guarded by a curtain of purple fire that would have looked a lot more threatening, if it hadn’t seemed pale and weak by comparison to the blackened flame hovering over Professor Quirrell’s shoulder.

Harry’s suspension of disbelief had already checked out on vacation at this point, so he didn’t say anything about how real-world security systems had the goal of distinguishing authorized from unauthorized personnel, which meant issuing challenges that behaved differently around people who were or weren’t supposed to be there. For example, a good security challenge would be testing whether the entrant knew a lock combination that only authorized people had been told, and a bad security challenge would be testing whether the entrant could brew a potion according to written instructions that had been helpfully included.

Professor Quirrell tossed the parchment toward Harry, and it fluttured to the ground between them. “What do you make of this?” said Professor Quirrell, who then stepped back so that Harry could come forward and pick up the parchment.

“Nope,” Harry said after skimming the parchment. “Testing whether the entrant can solve a ridiculously straightforward logic puzzle about the order of the ingredients is still not a challenge that behaves differently for authorized and unauthorized personnel. It doesn’t matter if you use a more interesting logic puzzle about three idols or a line of people wearing colored hats, you’re still completely missing the point.” “Look at the other side,” said Professor Quirrell.