Eliezer Yudkowsky - Harry Potter and the Methods of Rationality

Another pause.

"And to go about that, " the man in the corner said, "you will use your favorite tool, science."

"Of course."

The Defense Professor exhaled, almost like a sigh. "I suppose that makes sense of it."

"Are you willing to help, or not?" the boy said.

"What help do you seek?"

"Magic. Where does it come from?"

"I do not know," said the man.

"And neither does anyone else?"

"Oh, the situation is far worse than that, Mr. Potter. There is hardly a scholar of the esoteric who has not unraveled the nature of magic, and every one of them believes something different."

"Where do new spells come from? I keep reading about someone who invented a spell to do something-or-other but there's no mention of how ."

A shrug of robed shoulders. "Where do new books come from, Mr. Potter? Those who read many books sometimes become able to write them in turn. How? No one knows."

"There are books on how to write -"

"Reading them will not make you a famous playwright. After all such advice is accounted for, what remains is mystery. The invention of new spells is a similar mystery of purer form." The man's head tilted. "Such endeavors are dangerous. The saying is that one should either not have children, or else wait until after they are grown. There is a reason why so many innovators seem to hail from Gryffindor, rather than Ravenclaw as might be expected."

"And the more powerful sorts of magics?" the boy said.

"A legendary wizard might invent one sacrificial ritual in his life, and pass on the knowledge to his heirs. To try inventing five such would be suicide. That is why wizards of true power are those who have acquired ancient lore."

The boy nodded distantly. "So much for the direct solution, then. It would've been nice to just invent a spell for 'Raise Dead', 'Become God' or 'Summon Terminal'. Do you know anything about Atlantis?"

"Only what any scholar knows," the man said dryly. "If you would like to hear about the top eighteen standard theories - do not glare at me, Mr. Potter. If it were that simple, I would have done it many years earlier."

"I understand. Sorry."

There was a time of silence. The Defense Professor's gaze rested on the boy, the boy stared off seemingly at nothing.

"There's some magics I mean to learn. Spells I could've used earlier today, if I'd thought to study them beforehand." The boy's voice was cold. "Spells I'll need, if this sort of thing goes on happening. Most I expect I can just look up. Some I expect I can't."

The Defense Professor inclined his head. "I shall teach you almost any magic you wish to know, Mr. Potter. I do have some limits, but you may always ask. But what specifically do you seek? You lack the raw power for the Killing Curse and most other spells deemed forbidden -"

"That spell of cursed fire. I don't suppose it's a sacrificial ritual that even a child could use, if he dared?"

The Defense Professor's lips twitched. "It requires the permanent sacrifice of a drop of blood; your body would be lighter by that drop of blood, from that day forward. Not the sort of thing one would wish to do often, Mr. Potter. Strength of will is demanded for the cursed fire not to turn upon you and consume you; the usual practice is to first test one's will in lesser trials. And although it is not a primary element of the ritual, I am afraid that it does require more magic than you shall possess for another few years."

"Pity," the boy said. "It would've been nice to see the look on the enemy's face the next time they tried using a troll."

The Defense Professor inclined his head, his lips twitching again.

"What about Memory Charms? The Weasley twins were acting oddly and the Headmaster said he thinks they've been Obliviated. It seems to be one of the enemy's favorite tricks."

"Rule Eight," said the Defense Professor. "Any technique which is good enough to defeat me once is good enough to learn myself."

The boy smiled humorlessly. "And I once heard about an adult casting Obliviate while she was almost completely drained, so it must not take too much magic to cast. It's not even considered Unforgiveable, though I can't imagine why not. If I could've made Mr. Hagrid remember a different set of orders -"

"It is not that straightforward," said the Defense Professor. "You are not powerful enough to use the False Memory Charm, and even a simple Obliviation will stretch the edge of your current stamina. It is a dangerous art, illegal to use without Ministry authorization, and I would caution you not to use it under circumstances where it would be inconvenient to accidentally erase ten years of someone's life. I wish I could promise you that I would obtain one of those highly guarded tomes from the Department of Mysteries, and pass it to you beneath a disguised cover. But what I must actually tell you is that you will find the standard introductory text in the north-northwest stacks of the main Hogwarts library, filed under M."

"Seriously," the boy said flatly.

"Indeed."

"Thank you for your guidance, Professor."

"Your creativity has become a great deal more practical, Mr. Potter, since I have known you."

"Thank you for the compliment." The boy did not look up from where he was again gazing down at the wand held between his hands. "I would like to go back to thinking now. Please explain to them on my behalf what happens if I am disturbed."

The door to the storeroom clicked open, and Professor Quirrell stepped out. His face had a dead, emotionless look to it; she would have said that it reminded her of Severus, though Severus had never looked quite like that.

Even as the door clicked shut again, Minerva had thrown up a wordless Quieting barrier. The words spilled forth from her rapidly: "How did it go - you were in there for a while - is Harry talking now?"

Professor Quirrell paced swiftly across the room to the far wall near the entrance, looked back at her. The emotionlessness slid off his face, as though he were taking off a mask, leaving behind someone very grim. "I spoke to Mr. Potter as he expected me to speak, and avoided saying things that would annoy him. I do not think it consoled him. I do not think I have the knack."

"Thank you - it is good that he spoke at all -" She hesitated. "What did Mr. Potter say?"

"I am afraid that I promised him not to speak of it. And now... I think that I must visit the Hogwarts library."

"The library? "

"Yes," Professor Quirrell said. An uncharacteristic tension had come into his voice. "I intend to strengthen the security upon the Restricted Section with certain precautions of my own devising. The current wards are a joke. And Mr. Potter must be kept out of the Restricted Section at all costs. "

She stared at the Defense Professor, her heart suddenly in her throat.

Professor Quirrell continued speaking. "You will not tell the boy that I have said this much to you. You will confirm to Flitwick and Vector that the boy is to be diverted by the usual evasions if he asks precocious questions about spell creation. And though it is not my own area of expertise, Deputy Headmistress, if there is any way you can imagine to convince the boy to stop sinking further into his grief and madness - any way at all to undo the resolutions he is coming to - then I suggest you resort to it immediately ."

Shortly after, there was another knock upon the storeroom door.

"If you actually care about my mental health," the boy said without looking up, "you will go away, leave me alone, and wait for me to come down to dinner. This isn't helping."

The door opened, and the one who had waited outside stepped in.

"Seriously?" the boy said flatly.

The door closed and clicked behind Severus Snape.