Eliezer Yudkowsky - Harry Potter and the Methods of Rationality

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 probable that it was the Headmaster who framed Hermione?"

"Not necessarily, Mr. Potter." Professor Quirrell drained his teacup in one swallow and then set it down, the cup making a sharp rap as it descended. "There is also Severus Snape - though what he might think to gain from this, I could not guess. Thus he is not my prime suspect either."

"Then who is?" Harry said, somewhat puzzled. Professor Quirrell surely wasn't about to reply 'You-Know-Who' -

"The Aurors have a rule," said Professor Quirrell. "Investigate the victim. Many would-be criminals imagine that if they are the apparent victims of a crime, they shall not be suspected. So many criminals imagine it, indeed, that every senior Auror has seen it a dozen times over."

"You're not seriously trying to convince me that Hermione -"

The Defense Professor was giving Harry one of those slit-eyed looks that meant he was being stupid.

Draco? Draco had been interrogated under Veritaserum - but Lucius might have had enough control to subvert Aurors to... oh.

"You think Lucius Malfoy set up his own son? " Harry said.

"Why not?" Professor Quirrell said softly. "From Mr. Malfoy's recorded testimony, Mr. Potter, I gather that you enjoyed some success in changing Mr. Malfoy's political views. If Lucius Malfoy learned of that earlier... he might have decided that his former heir had become a liability."

"I don't buy it," Harry said flatly.

"You are being wantonly naive, Mr. Potter. The history books are full of family disputes turned murderous, for inconveniences and threats far less than those which Mr. Malfoy posed to his father. I suppose next you will tell me that Lord Malfoy of the Death Eaters is far too gentle to wish his son such harm." A tinge of heavy sarcasm.

"Well, yes, frankly," Harry said. "Love is real, Professor, a phenomenon with observable effects. Brains are real, emotions are real, and love is as much a part of the real world as apples and trees. If you made experimental predictions without taking parental love into account, you'd have a heck of a time explaining why my own parents didn't abandon me at an orphanage after the Incident with the Science Project."

The Defense Professor did not react to this at all.

Harry continued. "From what Draco says, Lucius prioritized him over important Wizengamot votes. That's significant evidence, since there's less expensive ways to fake love, if you just want to fake it. And it's not like the prior probability of a parent loving their child is low . I suppose it's possible that Lucius was just taking on the role of a loving father, and he renounced that role after he learned Draco was consorting with Muggleborns. But as the saying goes, Professor, one must distinguish possibility from probability."

"All the better the crime," the Defense Professor said, still in that soft tone, "if no one would believe it of him."

"And how would Lucius even Memory-Charm Hermione in the first place, without setting off the wards? He's not a Professor - oh, right, you think it's Professor Snape."

"Wrong," said the Defense Professor. "Lucius Malfoy would trust no servant with that mission. But suppose some Hogwarts Professor, intelligent enough to cast a well-formed Memory Charm but of no great fighting ability, is visiting Hogsmeade. From a dark alley the black-clad form of Malfoy steps forth - he would go in person, for this - and speaks to her a single word."

" Imperio ."

" Legilimens, rather," said Professor Quirrell. "I do not know if the Hogwarts wards would trigger for a returning Professor under the Imperius Curse. And if I do not know, Malfoy probably does not know either. But Malfoy is a perfect Occlumens at least; he might be able to use Legilimency. And for the target...perhaps Aurora Sinistra; none would question the Astronomy Professor moving about at night."

"Or even more obviously, Professor Sprout," said Harry. "Since she's the last person anyone would suspect."

The Defense Professor hesitated minutely. "Perhaps."

"Actually," Harry said then, putting a thoughtful frown on his face, "I don't suppose you know offhand if any of the current Professors at Hogwarts were around back when Mr. Hagrid got framed in 1943?"

"Dumbledore taught Transfiguration, Kettleburn taught Magical Creatures, and Vector taught Arithmancy," Professor Quirrell said at once. "And I believe that Bathsheda Babbling, now of Ancient Runes, was then a Ravenclaw prefect. But Mr. Potter, there is no reason to suppose that anyone besides You-Know-Who was involved in that affair."

Harry shrugged artfully. "Seemed worth asking the question, just to check. Anyway, Professor, I agree it's possible that some outsider Legilimized a member of Hogwarts staff - and then Obliviated them afterward, there's no way anyone would forget that part. But I don't think Lucius Malfoy is a probable candidate for the mastermind. It's possible but not probable that all of Lucius's apparent love for Draco was just a sense of duty, and that it all went up in a puff of smoke. It's possible though not probable that everything Lucius did in front of the Wizengamot was just an act. People's outsides do not always resemble their insides, like you said. But there's one piece of evidence that doesn't fit at all."

"And that would be?" said the Defense Professor, his eyes half-lidded.

"Lucius tried to reject a hundred thousand Galleons for Hermione's life. I saw how surprised the Wizengamot was, when Lucius said he was refusing it despite the rules of honor. The Wizengamot didn't expect that of him. Why wouldn't he just take the money while acting all indignant and pretending to grit his teeth? He wouldn't actually care that much about throwing Hermione into Azkaban."

There was a pause. "Perhaps the role he was playing ran away with him," said Professor Quirrell. "It does happen, Mr. Potter, in the heat of the moment."

"Perhaps," Harry said. "But it's still one more improbability to be postulated - and by the time you have to add up that many excuses in a theory, it can't be at the top of the list anymore. Anything else in particular you think I ought to think about, within the range of all other possibilities?"

There was a long silence. The Defense Professor's eyes dropped down to look at the empty teacup before them, seeming unusually distant.

"I suppose I can think of one final suspect," the Defense Professor said at last.

Harry nodded.

The Defense Professor didn't seem to notice, but only spoke on. "Has the Headmaster has told you anything - even a hint - about Professor Trelawney's prophecy?"

" Huh? " Harry said automatically, converting his own sudden shock into the best dissembling he could manage. It probably was at the wrong level to fool Professor Quirrell but Harry certainly couldn't take time to think before replying - wait, but how on Earth would Professor Quirrell know about that - "Professor Trelawney made a prophecy?"