Harry Potter and the Methods of Rationality

"I must be sure. Take off that ring, Harry, and place it upon my desk."

Slowly, Harry did so, removing the gem and setting the ring off to the other side of the desk.

Dumbledore pointed his wand at the gem and -

A large, undistinguished grey rock jumped into the air from the force of its sudden expansion, hit some invisible barrier in the air above, and then fell with a loud crack upon the Headmaster's desk,

"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.