Eliezer Yudkowsky - Harry Potter and the Methods of Rationality

"Flush of gratitude and all that," Mad-Eye Moody said sourly. "It didn't last, but at least James and Lily got a fancy title and a useless medal to take to their graves. But that's leaving out eight years of complete horror after Monroe disappeared and Regulus Black - he was Monroe's private source in the Death Eaters, we're pretty sure - was executed by Voldie. Like a dam breaking and gore flooding out, drowning the whole country. Albus bloody Dumbledore himself had to step into Monroe's shoes, and that was barely enough for us to survive."

Harry listened with an odd sense of unreality. Some of it felt right, matched up with observation - especially with the speech Professor Quirrell had made before Christmas - and yet...

This was Professor Quirrell they were talking about.

"So that's who the Department thinks is your Defense Professor," Mad-Eye Moody finished up his account. "Now what do you think, son?"

"Well..." Harry said slowly. It is also possible to have a mask behind the mask. "The obvious next thought is that this 'David Monroe' person died in the war after all, and this is just someone else pretending to be David Monroe pretending to be Quirinus Quirrell."

"That's obvious? " said Professor McGonagall. "Dear Merlin..."

"Really, boy?" said Mad-Eye Moody, his blue eye spinning rapidly. "I'd say that's a little... paranoid. "

You don't know Professor Quirrell, Harry did not say. "It's an easy theory to test," Harry said out loud. "Just check whether the Defense Professor remembers something about the war that the real David Monroe would've known. Though I suppose, if he's playing the part of David Monroe pretending to be someone else, he has a good excuse to pretend he's pretending he doesn't know what you're talking about -"

"A little paranoid," said the scarred man, his voice rising. " Not paranoid enough! CONSTANT VIGILANCE! Think about it, lad - what if the real David Monroe never came back from Albania?"

There was a pause.

"I see..." Harry said.

"Of course you do," Professor McGonagall said. "Don't mind me, please. I'll just sit here quietly going mad."

"In this line of work, if you survive, you learn that there's three kinds of Dark Wizards," Moody said grimly; his wand wasn't pointed at anyone, it was angled slightly downward, but it was in his hand. It had never left his hand since the moment he'd entered the room. "There's Dark Wizards that have one name. There's Dark Wizards that have two names. And there's Dark Wizards that change names like you and I change clothes. I saw 'Monroe' go through three Death Eaters like he was snapping twigs. There's not many wizards that good at age forty-five. Dumbledore, maybe, but not many others."

"Perhaps that is true," said the Potions Master from where he was lurking. "But what of it, Mad-Eye? Whatever his identity, Monroe was surely the Dark Lord's enemy. I've heard Death Eaters curse his name even after they thought him dead. They feared him well."

"So far as Defense Professors are concerned," Professor McGonagall said primly, "I shall take it and be grateful."

Moody swung around to glare at her. "Just where the devil was 'Monroe' all those years he was gone, eh? Maybe he thought he could make a name for himself in Britain by opposing Voldie, and vanished away when he found out he was wrong. Then why'd he come back now, hah? What's his new plan?"

"He, ah..." Harry ventured tentatively. "He says he always wanted to be a great Defense Professor because all the best fighting wizards have taught at Hogwarts. And he kind of is being an incredibly good Defense Professor, actually... I mean, if he just wanted to keep up a disguise, he could get away with much sloppier work..."

Professor McGonagall was nodding firmly.

"Naive," Moody said flatly. "I suppose you all haven't wondered if your Defense Professor set up the whole House of Monroe to be wiped out?"

" What? " cried Professor McGonagall.

"Our mystery wizard hears about a missing kid from a Most Ancient House of Britain," Moody said. "Steps into the shoes of 'David Monroe', but stays away from the real Monroe family. But eventually the House is bound to notice something wrong. So this imposter somehow prods Voldie into wiping them all out - maybe leaked a password they'd given him for their wards - and then he was a Lord of the Wizengamot!"

There seemed to be a fight going on inside Harry's mind between Hufflepuff One, who'd never trusted the Defense Professor in the first place; and Hufflepuff Two, who was far too loyal to Harry's friend, Professor Quirrell, to believe something like that just because Moody said so.

It is kind of obvious, though, observed his Slytherin part. I mean, do you actually believe that under natural circumstances, anyone would end up as the last heir to a Most Ancient House AND Lord Voldemort killed his family AND he has to avenge his martial arts sensei? If anything I'd say he went too far over the top in setting up his new identity as the ideal literary hero. That sort of thing doesn't happen in real life.

This from an orphan who was raised unaware of his heritage, commented Harry's Inner Critic. With a prophecy about him. You know, I don't think we've ever read a story about two equally destined heroes competing to see who's cliched enough to take down the villain -

Yes, replied the central Harry over the distant vroop-ing noise in the background, it's a very sad life we lead and YOU'RE NOT HELPING.

There's only one thing to do at this point, said Ravenclaw. And we all know what it is, so why argue?

But, Harry replied, how do we test experimentally whether or not Professor Quirrell is the original David Monroe? I mean, what sort of observable behaves differently, depending on whether he's the real David Monroe or an impostor?

"What do you want me to do about it, Mad-Eye?" Professor McGonagall was demanding. "I can't -"

"You can," the scarred man said, glaring at her fiercely. "Just fire the bloody Defense Professor."

"You say that every year," said Professor McGonagall.

"Yes, and I'm always right!"

"Constant vigilance or no, Alastor, the students must be taught!"

Moody snorted. "Pfah! I swear the curse gets worse every year, as you lot get more and more reluctant to let them go. Your precious Professor Quirrell would have to be Grindelwald in disguise, to get himself sent off!"

"Is he?" Harry couldn't help asking. "I mean, could he actually be -"

"I check Grindie's cell every two months," Moody said. "He was there in March."

"Could the person in the cell be a ringer?"

"I administer a blood test for his identity, son."

"Where do you keep the blood you use as a reference?"

"In a safe place." Something like a smile was stretching the scarred lips. "Have you considered the Auror Office after you graduate?"

"Alastor," Professor McGonagall said reluctantly. "The Defense Professor does have a... health condition. I suppose you will call it suspicious in itself - but it is by no means certain that it will be any ill-doing on his part which prevents us from renewing his employment."

"Yes, his little naptimes," Moody said darkly. "Amelia thinks he stepped into the path of a high-level curse. Sounds to me more like a Dark ritual gone wrong!"

"You've no proof of that!" Professor McGonagall said.

"That man might as well be wearing a sign saying 'Dark Wizard' in glowing green letters over his head."

"Ah..." Harry said. It didn't seem like an especially good time to ask what Mr. Moody thought of the 'not all sacrificial rituals are evil' standpoint. "Excuse me, but you said earlier that Professor Quirrell - I mean the old David Monroe - I mean the Monroe from the seventies - anyway, you said that person used the Killing Curse. What does that imply? Does somebody have to be a Dark Wizard to use it?"