Harry Potter and the Methods of Rationality

There was some laughter from the Slytherins, but they were laughing with Harry, not at him.

Everyone else was looking rather horrified.

"But Mr. Potter has now demonstrated why he is the most dangerous student in the classroom. I asked for unaccustomed uses of items in this room for combat. Mr. Potter could have suggested using a desk to block a curse, or using a chair to trip an oncoming enemy, or wrapping cloth around his arm to create an improvised shield. Instead, every single use that Mr. Potter named was offensive rather than defensive, and either fatal or potentially fatal."

What? Wait, that couldn't be true... Harry had a sudden sense of vertigo as he tried to remember what exactly he'd suggested, surely there had to be a counterexample...

"And that," Professor Quirrell said, "is why Mr. Potter's ideas were so strange and useless - because he had to reach far into the impractical in order to meet his standard of killing the enemy. To him, any idea which fell short of that was not worth considering. This reflects a quality that we might call intent to kill. I have it. Harry Potter has it, which is how he could stare down five older Slytherins. Draco Malfoy does not have it, not yet. Mr. Malfoy would hardly shrink from talk of ordinary murder, but even he was shocked - yes you were Mr. Malfoy, I was watching your face - when Mr. Potter described how to use his classmates' bodies as raw material. There are censors inside your mind which make you flinch away from thoughts like that. Mr. Potter thinks purely of killing the enemy, he will grasp at any means to do so, he does not flinch, his censors are off. Even though his youthful genius is so undisciplined and impractical as to be useless, his intent to kill makes Harry Potter the Most Dangerous Student in the Classroom. One final point to him - no, let us make that a point to Ravenclaw - for this indispensable requisite of a true fighting wizard."

Harry's mouth gaped open in speechless shock as he searched frantically for something to say to this. That is so completely not what I am about!

But he could see that the other students were starting to believe it. Harry's mind was flipping through possible denials and not finding anything that could stand up against the authoritative voice of Professor Quirrell. The best Harry had come up with was "I'm not a psychopath, I'm just very creative" and that sounded kind of ominous. He needed to say something unexpected, something that would make people stop and reconsider -

"And now," Professor Quirrell said. "Mr. Potter. Fire."

Nothing happened, of course.

"Ah, well," said Professor Quirrell. He sighed. "I suppose we must all start somewhere. Mr. Potter, select any student you please for a Simple Strike Hex. You will do so before I dismiss your class for the day. If you do not, I will begin deducting House points, and I will keep on deducting them until you do."

Harry carefully raised his wand. He had to do that much, or Professor Quirrell might start deducting House points right away.

Slowly, as though on a roasting platter, Harry turned to face the Slytherins.

And Harry's eyes met Draco's.

Draco Malfoy didn't look the slightest bit afraid. The blonde-haired boy wasn't giving any visible sign of assent such as Harry had given Hermione, but then he could hardly be expected to do so. The other Slytherins would think that rather odd.

"Why the hesitation?" said Professor Quirrell. "Surely there's only one obvious choice."

"Yes," Harry said. "Only one obvious choice."

Harry twisted the wand and said "Ma-ha-su!"

There was complete silence in the classroom.

Harry shook his left arm, trying to get rid of the lingering sting.

There was more silence.

Finally Professor Quirrell sighed. "Yes, quite ingenious, but there was a lesson to be taught and you dodged it. One point from Ravenclaw for showing off your own cleverness at the expense of the actual goal. Class dismissed."

And before anyone else could say anything, Harry sang out:

"Just kidding! RAVENCLAW!"

There was silence for a brief moment after that, a sound of people thinking, and then the murmurs started and rapidly rose to a roar of conversation.

Harry turned towards Professor Quirrell, the two of them needed to talk -

Quirrell had slumped over and was trudging back to his chair.

No. Not acceptable. They really needed to talk. Stuff the zombie act, Professor Quirrell would probably wake up if Harry poked him a couple of times. Harry started forward -

WRONG

DON'T

BAD IDEA

Harry swayed and stopped in his tracks, feeling dizzy.

And then a flock of Ravenclaws descended on him and the discussions began.

Chapter 17: Locating the Hypothesis

You have always been J. K. Rowling.

Historical note: In the Roman calendar, the "Ides" of a month referred to the 15th day of March, May, July, and October, and to the 13th day of all other months.

"You start to see the