Eliezer Yudkowsky - Harry Potter and the Methods of Rationality

Dean Thomas cast his white bear again, even in the Dementor's presence; and Ron Weasley put up an adequate shield of sparkling mist. Which concluded the day, so far as everyone else was concerned, and Professor Flitwick began to herd the students back to Hogwarts. When it was clear that Harry meant to stay behind, Professor Flitwick looked at him quizzically; and Harry, for his part, glanced significantly at Dumbledore. Harry didn't know what Professor Flitwick made of that, but after a sharp gaze of warning, his Head of House departed.

And so remained only Harry, Professor Quirrell, Headmaster Dumbledore, and an Auror trio.

It would have been better to get rid of the trio first, but Harry couldn't think of a good way to do that.

"All right," said Auror Komodo, "let's take it back."

"Excuse me," Harry said. "I'd like to have another go at the Dementor."

Harry's request met with a certain amount of opposition of the you're completely insane variety, though it was only Auror Butnaru who actually said that out loud.

"Fawkes told me to," Harry said.

This did not overcome all the opposition, despite the look of shock it produced on Dumbledore's face. The argument went on, and it was starting to wear the edges off the phoenix's remaining peace, which annoyed Harry, though only a little.

"Look," Harry said, "I'm pretty sure I know what I was doing wrong before. There's a kind of person who has to use a different sort of warm and happy thought. Just let me try it, okay?"

This did not prove persuasive either.

"I think," Professor Quirrell said finally, staring at Harry with narrowed eyes, "that if we do not allow him to do this under supervision, he may, at some point or another, sneak off and look for a Dementor on his own. Do I accuse you falsely, Mr. Potter?"

There was an appalled pause at this. It seemed like a good time to play his trump card.

"I don't mind if the Headmaster keeps his own Patronus up," Harry said. For I will be in the presence of a Dementor just the same, Patronus or no.

There was confusion at this, even Professor Quirrell looked puzzled; but the Headmaster finally acceded, since it didn't seem likely that Harry could be hurt through four Patronuses.

If the Dementor could not reach through your Patronus on some level, Albus Dumbledore, you would not see a naked man painful to look upon...

Harry didn't say it out loud, for obvious reasons.

And they began to walk toward the Dementor.

"Headmaster," Harry said, "suppose the Ravenclaw door asked you this riddle: What lies at the center of a Dementor? What would you say?"

"Fear," said the Headmaster.

It was a simple enough mistake. The Dementor approached, and the fear came over you. The fear hurt, you felt the fear weakening you, you wanted the fear to go away.

It was natural to think the fear was the problem.

So they'd concluded that the Dementor was a creature of pure fear, that there was nothing there to fear but fear itself, that the Dementor couldn't hurt you if you weren't afraid...

But...

What lies at the center of a Dementor?

Fear.

What is so horrible that the mind refuses to see it?

Fear.

What is impossible to kill?

Fear.

...it didn't quite fit, once you thought about it.

Though it was clear enough why people would be reluctant to look beyond the first answer.

People understood fear.

People knew what they were supposed to do about fear.

So, faced with a Dementor, it wouldn't exactly be comforting to ask: 'What if the fear is just a side effect rather than the main problem?'

They had come very close to the Dementor's cage guarded by four Patronuses, when there came sharp intakes of breath from the three Aurors and Professor Quirrell. Everyone's faces turned to look at the Dementor, seeming to listen; there was horror on Auror Goryanof's face.

Then Professor Quirrell raised his head, his face hard, and spat toward the Dementor.

"It did not like having its prey taken from it, I suppose," Dumbledore said quietly. "Well. If it becomes necessary, Quirinus, there will always be a refuge for you at Hogwarts."

"What did it say?" said Harry.

Every head swung to stare at him.

"You didn't hear it...?" Dumbledore said.

Harry shook his head.

"It said to me," said Professor Quirrell, "that it knew me, and that it would hunt me down someday, wherever I tried to hide." His face was rigid, showing no fright.

"Ah," Harry said. "I wouldn't worry about that, Professor Quirrell." It's not like Dementors can actually talk, or think; the structure they have is borrowed from your own mind and expectations...

Now everyone was giving him very strange looks. The Aurors were glancing nervously at each other, at the Dementor, at Harry.

And they stood directly before the Dementor's cage.

"They are wounds in the world," Harry said. "It's just a wild guess, but I'm guessing the one who said that was Godric Gryffindor."

"Yes..." said Dumbledore. "How did you know?"

It is a common misconception , thought Harry, that all the best rationalists are Sorted into Ravenclaw, leaving none for other Houses. This is not so; being Sorted into Ravenclaw indicates that your strongest virtue is curiosity, wondering and desiring to know the true answer. And this is not the only virtue a rationalist needs. Sometimes you have to work hard on a problem, and stick to it for a while. Sometimes you need a clever plan for finding out. And sometimes what you need more than anything else to see an answer, is the courage to face it...

Harry's gaze went to what lay beneath the cloak, the horror far worse than any decaying mummy. Rowena Ravenclaw might also have known, for it was an obvious enough riddle once you saw it as a riddle.

And it was also obvious why the Patronuses were animals. The animals didn't know, and so were sheltered from the fear.

But Harry knew, and would always know, and would never be able to forget. He'd tried to teach himself to face reality without flinching, and though Harry had not yet mastered that art, still those grooves had been worn into his mind, the learned reflex to look toward the painful thought instead of away. Harry would never be able to forget by thinking warm happy thoughts about something else, and that was why the spell hadn't worked for him.

So Harry would think a warm happy thought that wasn't about something else.

Harry drew forth his wand that Professor Flitwick had returned to him, put his feet into the beginning stance for the Patronus Charm.

Within his mind, Harry discarded the last remnants of the peace of the phoenix, put aside the calm, the dreamlike state, remembered instead Fawkes's piercing cry, and roused himself for battle. Called upon all the pieces and elements of himself to awaken. Raised up within himself all the strength that the Patronus Charm could ever draw upon, to put himself into the right frame of mind for the final warm and happy thought; remembered all bright things.

The books his father had bought him.

Mum's smile when Harry had handmade her a mother's day card, an elaborate thing that had used half a pound of spare electronics parts from the garage to flash lights and beep a little tune, and had taken him three days to make.

Professor McGonagall telling him that his parents had died well, protecting him. As they had.

Realizing that Hermione was keeping up with him and even running faster, that they could be true rivals and friends.

Coaxing Draco out of the darkness, watching him slowly move toward the light.

Neville and Seamus and Lavender and Dean and everyone else who looked up to him, everyone that he would have fought to protect if anything threatened Hogwarts.