Harry Potter and the Methods of Rationality

took me three tries to get him. Plus, like I said, in a real fight Mr. Moody could've turned himself invisible, or put up shields -"

"Don't go relying too much on shields, boy," Mad-Eye said. The leather-clad Auror took another sip from his restorative flask. "What you learn in your first year at the academy doesn't stay true forever, not against the strongest Dark Wizards. Every shield ever made, there's some curse that goes straight through it, if you're not quick enough to cast the counter. And there's one curse that goes through everything, and it's a curse any Death Eater will use."

Harry Potter nodded gravely. "Right, some spells are impossible to block. I'll remember that, in case anyone casts the Killing Curse at me. Again."

"That kind of cleverness gets people killed, boy, and don't you forget it."

A sad-sounding sigh from the Boy-Who-Lived. "I know. Sorry."

"So, son. You had something to say about when Albus and I go after Lockhart?"

Harry opened his mouth, then paused. "I won't tell you how to run a war," the Boy-Who-Lived said eventually. "I don't have any experience at that. All I know is that there are consequences. Please be advised that my own assessment is that Lockhart is probably innocent, so if you can avoid hurting him without too much risk -" The boy shrugged. "I don't know the cost. Just please, if you can, be careful not to hurt him if he's innocent."

"If I can," said Moody.

"And - you're aiming to look through his mind for evidence about the Dark Lord, aren't you? I don't know what the rules are in magical Britain about admissible evidence - but everyone's always guilty of breaking some law or another, there's just too many laws. So if it's not about the Dark Lord, don't turn him in to the Ministry, just Obliviate him and go, okay?"

Moody frowned. "Son, nobody gains power that fast without being up to something."

"Then leave it for the ordinary Aurors, if and when they find evidence the ordinary way. Please, Mr. Moody. Call it a quirk of my Muggle upbringing, but if it's not about the war I don't want us to be the evil police who break into people's houses in the middle of the night, rummage through their minds and send them off to Azkaban."

"I don't see the sense of it, son, but I suppose I could do you the favor."

"Is there aught else, Alastor?" inquired Albus.

"Yes," said Moody. "About that Defense Professor of yours -"

Hypothesis: Gilderoy Lockhart: END

Hypothesis: Dumbledore

(April 9th, 1992, 5:32pm)

As Professor Quirrell slowly raised up his tea, the teacup jerked in midair, sending the dark translucent liquid just barely slopping over the side, so that only three single drops crawled down the side of the teacup. Harry would have missed it, if he hadn't happened to be watching closely; for Professor Quirrell's hand was perfectly steady on the cup before and after.

If that small jerky motion advanced to a constant tremor, it would be the end of any non-wandless magic for the Defense Professor. Wandwork had no room for trembling fingers. How much that would actually handicap Professor Quirrell, if at all, Harry couldn't guess. The Defense Professor was certainly capable of wandless magic, yet still tended to use a wand for larger things - but for him that might only be a convenience...

"Insanity," said Professor Quirrell, as he carefully sipped from his tea - he was looking at the teacup, not at Harry, which was unusual for him - "can be a signature all its own."

The Defense Professor's small office was silent, the sound-warded room quiet in a way the Headmaster's office never could be. Sometimes the two of them both happened to finish exhaling or inhaling at the same time; and then there was an auditory emptiness that was almost a sound in itself.

"I'll agree with that in one sense," Harry said. "If somebody tells me that everyone is staring at them and that their underwear is being dusted with thought-controlling powder, I know they're psychotic, because that's the standard signature of psychosis. But if you tell me that anything confusing points to Albus Dumbledore as a suspect, that seems... overreaching. Just because I can't see a purpose doesn't mean there is no purpose."

"Purposeless?" said Professor Quirrell. "Oh, but the madness of Dumbledore is not that he is purposeless, but that he has too many purposes. The Headmaster might have planned this to make Lucius Malfoy throw away his game for vengeance on you - or it might be a dozen other plots. Who knows what the Headmaster thinks he has reason to do, when he has found reason to do so many strange things already?"

Harry had politely declined tea, even knowing that Professor Quirrell would know what it meant. He'd considered bringing his own can of soda - but had decided against that as well, after realizing how easy it would be for the Defense Professor to teleport in a bit of potion, even if the two of them couldn't touch each other with direct magic.

"I have seen a little now of Dumbledore," Harry said. "Unless everything I have seen is a lie, I find it difficult to believe that he would plot to send any Hogwarts student to Azkaban. Ever."

"Ah," the Defense Professor said softly, the tiny reflection of the teacup gleaming in his pale eyes. "But perhaps that is another signature, Mr. Potter. You have not yet comprehended the perspective of a man like Dumbledore. If he must, in some sufficiently noble cause, sacrifice a student - why, who would he choose, but she who declared herself a heroine?"

That gave Harry some pause. It might just be hindsight bias, but that did seem to concentrate some of that hypotheses's probability mass onto framing Hermione in particular. Similarly, Professor Quirrell had predicted in advance that Dumbledore might target Draco...

But if it's you behind all of this, Professor, you might have shaped your plans to frame the Headmaster, and taken care to cast suspicion on him in advance.

The concept of 'evidence' had something of a different meaning, when you were dealing with someone who had declared themselves to play the game at 'one level higher than you'.

"I see your point, Professor," Harry said evenly, giving no hint of his other thoughts. "So you think it most