Eliezer Yudkowsky - Harry Potter and the Methods of Rationality

"There's another half-hour of work for me, Transfiguring it again," Harry said evenly.

Dumbledore resumed his examination. Harry had to remove his left shoe, and take off the toe-ring that was his emergency portkey if someone kidnapped him and took him outside the wards of Hogwarts (and didn't put up anti-Apparition, anti-portkey, anti-phoenix, and anti-time-looping wards, which Severus had warned Harry that any inner-circle Death Eater would certainly do). It was verified that the magic radiating from the toe-ring was indeed the magic of a portkey, and not the magic of a Transfiguration. The rest of Harry was deemed clear.

Not long after, the Potions Master returned, bearing Harry's pouch, and several other magical things which had been in Harry's trunk, which the Headmaster also examined, one by one, even to all the items remaining within the healer's kit.

"Can I go now?" Harry said when it was all done, putting as much cold as he could into his voice. He took up his pouch, and began the process of feeding the grey rock into it. The empty ring went back on his finger.

The old wizard breathed out, slipping his wand back into his sleeve. "I am sorry," he said. "I had to know. Harry... the Dark Lord has taken Hermione Granger's remains, it seems. I cannot think of anything he would gain thereby, except to send her corpse against you as an Inferius. Severus shall give you certain potions to keep about your person. Be warned now, and be prepared for when you must do what must be done."

"Will the Inferius have Hermione's mind?"

"No -"

"Then it's not her. Can I go? At least to change out of my pyjamas."

"There is other news, but I shall be brief. The wards of Hogwarts record that no foreign creature has entered, and that it was the Defense Professor who killed Hermione Granger."

"Um," Harry said.

Thought 1: But I saw the troll kill Hermione.

Thought 2: Professor Quirrell Memory-Charmed me and set up the scene that Dumbledore saw when he arrived.

Thought 3: Professor Quirrell can't do that, his magic can't touch mine. I saw that in Azkaban -

Thought 4: Can I trust those memories?

Thought 5: There was clearly some sort of debacle at Azkaban, we wouldn't have needed a rocket if Professor Quirrell hadn't fallen unconscious, and why'd he be unconscious if not -

Thought 6: Did I ever actually go to Azkaban at all?

Thought 7: I clearly practiced controlling Dementors at some point before I scared that Dementor in the Wizengamot. And that was in the newspapers.

Thought 8: Am I accurately remembering the newspapers?

"Um," Harry said again. "That spell seriously ought to be Unforgiveable. You think Professor Quirrell could have Memory-Charmed -"

"No. I went back through time and placed certain instruments to record Hermione's last battle, which I could not quite bear to watch in my own person." The old wizard looked very grim indeed. "Your guess was right, Harry Potter. Voldemort sabotaged everything we gave Hermione to protect her. Her broomstick lay dead in her hands. Her invisibility cloak did not conceal her. The troll walked in the sunlight unharmed; it was no stray creature, but a weapon pure and aimed. And it was indeed the troll who killed her, with strength alone, so that my wards and webs to detect hostile magics went for naught. The Defense Professor never crossed her path."

Harry swallowed, shut his eyes, and thought. "So this was an attempted frame on Professor Quirrell. Somehow. It does seem to be the enemy's modus operandi. Troll eats Hermione Granger, check the wards, oh look actually the Defense Professor did it, same as last year... no. No, that can't be right."

"Why not, Mr. Potter?" said the Potions Master. "It seems obvious enough to me -"

"That's the problem."

The enemy is smart.

Slowly the fog of sleep was drifting out of Harry's mind, and after a full night's sleep his brain could see the things which hadn't been obvious the day before.

Under standard literary convention... the enemy wasn't supposed to look over what you'd done, sabotage the magic items you'd handed out, and then send out a troll rendered undetectable by some means the heroes couldn't figure out even after the fact, so that you might as well have not defended yourself at all. In a book, the point-of-view usually stayed on the main characters. Having the enemy just bypass all the protagonists' work, as a result of planning and actions taken out of literary sight, would be a diabolus ex machina, and dramatically unsatisfying.

But in real life the enemy would think that they were the main character, and they would also be clever, and think things through in advance, even if you didn't see them do it. That was why everything about this felt so disjointed, with parts unexplained and seemingly inexplicable. How had Lucius felt, when Harry had threatened Dumbledore with breaking Azkaban? How had the Aurors above Azkaban felt, seeing the broomstick rise up on a torch of fire?

The enemy is smart.

"The enemy knew perfectly well that you'd turn back time to check what really happened to Hermione, especially since the troll getting into Hogwarts at all tells us that somebody can fool the wards." Harry shut his eyes, thinking harder, trying to put himself into the enemy's shoes. Why would he, or his dark side, have done something like - "We're meant to conclude that the enemy has control of what the wards tell us. But that's actually something the enemy can only do with difficulty, or under special conditions; they're trying to create a false appearance of omnipotence." Like I would. "Later, hypothetically, the wards show Professor Sinistra killing someone. We think the wards are just being fooled again, but really, Professor Sinistra was Legilimized and she did do it."

"Unless that is precisely what the Dark Lord expects us to think," said Severus Snape, his brow furrowed in concentration. "In which case he does have control of the wards, and Professor Sinistra will be innocent."

"Does the Dark Lord really use plots with that many levels of meta -"

"Yes," said Dumbledore and Severus.

Harry nodded distantly. "Then this could be a setup to either make us think the wards are telling the truth when they're lying, or a setup to make us think the wards are lying when they're telling the truth, depending on what level the enemy expects us to reason at. But if the enemy is planning to make us trust the wards - we would have trusted the wards anyway, if we'd been given no reason to distrust them. So there's no need to go to all the work of framing Professor Quirrell in a way that we would realize we were intended to discover, just to trick us into going meta -"

"Not so," said Dumbledore. "If Voldemort has not fully mastered the wards, then the wards had to believe that some Professor's hand was at work. Else they would have cried out at Miss Granger's injury, and not only upon her death."

Harry reached up a hand and rubbed at his brow, just beneath his hair.

Okay, serious question. If the enemy is that smart, why the heck am I still alive? Is it seriously that hard to poison someone, are there Charms and Potions and bezoars which can cure me of literally anything that could be slipped into my breakfast? Would the wards record it, trace the magic of the murderer?

Could my scar contain the fragment of soul that's keeping the Dark Lord anchored to the world, so he doesn't want to kill me? Instead he's trying to drive off all my friends to weaken my spirit so he can take over my body? It'd explain the Parselmouth thing. The Sorting Hat might not be able to detect a lich-phylactery-thingy. Obvious problem 1, the Dark Lord is supposed to have made his lich-phylactery-thingy in 1943 by killing whatshername and framing Mr. Hagrid. Obvious problem 2, there's no such thing as souls.