Eliezer Yudkowsky - Harry Potter and the Methods of Rationality

"I don't want to say goodbye," Neville said. His voice was trembling, but he managed not to cry. "I want to stay here and fight with you against - against whatever's happening."

The empty air moved closer to him, and embraced him in a hug, and Harry Potter's voice whispered, "Tough luck."

The third meeting

(10:31am, April 17th 1992)

Spring had begun, the late-morning air still crisp with the leavings of winter. Daffodils had bloomed amid the sprouting grass of the forest, the gentle yellow petals with their golden hearts dangling limply from their dead, grayed stems, wounded or killed by one of the sudden frosts that you often saw in April. In the Forbidden Forest there would be stranger lifeforms, centaurs and unicorns at the least, and Harry had heard allegations of werewolves. Though from what Harry had read of real-life werewolves, that did not make the slightest bit of sense.

Harry didn't venture anywhere near the border of the Forbidden Forest, since there was no reason to take the risk. He walked invisibly among the more ordinary life-forms of the permitted woods, wand in hand, a broomstick strapped to his back for easier access, just in case. He was not actually afraid; Harry thought it odd that he didn't feel afraid. The state of constant vigilance, readiness for fight or flight, failed to feel burdensome or even abnormal.

On the edges of the permitted woods Harry walked, his feet never straying near the beaten path where he might be more easily found, never leaving sight of Hogwarts's windows. Harry had set the alarm upon his mechanical watch to tell him when it was lunchtime, since he couldn't actually look at his wrist, being invisible and all that. It raised the question of how his eyeglasses worked while he was wearing the Cloak. For that matter the Law of the Excluded Middle seemed to imply that either the rhodopsin complexes in his retina were absorbing photons and transducing them to neural spikes, or alternatively, those photons were going straight through his body and out the other side, but not both. It really did seem increasingly likely that invisibility cloaks let you see outward while being invisible yourself because, on some fundamental level, that was how the caster had - not wanted - but implicitly believed - that invisibility should work.

Whereupon you had to wonder whether anyone had tried Confunding or Legilimizing someone into implicitly and matter-of-factly believing that Fixus Everythingus ought to be an easy first-year Charm, and then trying to invent it.

Or maybe find a worthy Muggleborn in a country that didn't identify Muggleborn children, and tell them some extensive lies, fake up a surrounding story and corresponding evidence, so that, from the very beginning, they'd have a different idea of what magic could do. Though apparently they'd still have to learn a number of previous Charms before they became capable of inventing their own...

It might not work. Surely there'd been some organically insane wizards who'd truly believed in their own possibility of godhood, and yet had failed to become god. But even the insane had probably believed the ascension spell ought to be some grandiose dramatic ritual and not something you did with a carefully composed twitch of your wand and the incantation Becomus Goddus.

Harry was already pretty sure it wouldn't be that easy. But then the question was, why not? What pattern had his brain learned? Could the reason be predicted in advance?

A slight fringe of apprehension crept through Harry then, a tinge of worry, as he contemplated this question. The nameless concern sharpened, grew greater -

Professor Quirrell?

"Mr. Potter," a soft voice called from behind him.

Harry spun, his hand going to the Time-Turner beneath his cloak; again the principle of being ready to flee upon an instant's notice felt only ordinary.

Slowly, palms empty and turned outward, Professor Quirrell was walking towards him within the forests' outskirts, coming from the general direction of the Hogwarts castle.

"Mr. Potter," Professor Quirrell said again. "I know that you're here. You know that I know that you're here. I must speak to you."

Still Harry said nothing. Professor Quirrell hadn't actually said what this was about, and Harry's sunlit morning walk about the forest edge had produced a mood of silence within him.

Professor Quirrell took a small step to the left, a step forward, another to the right. He tilted his head with a look of calculation, and then he walked almost directly towards where Harry stood, halted a few paces off with the sense of doom enflamed to the height of bearability.

"Are you still resolved upon your course?" Professor Quirrell said. "The same course you spoke of yesterday?"

Again Harry did not reply.

Professor Quirrell sighed. "There is much I have done for you," the man said. "Whatever else you may wonder of me, you cannot deny that. I am calling in some of the debt. Talk to me, Mr. Potter."

I don't feel like doing this right now, Harry thought; then: Oh, right.

Two hours later, after Harry had spun the Time-Turner once, noted down the exact time and memorized his exact location, spent another hour walking, went inside and told Professor McGonagall that he was currently talking to the Defense Professor in the woods outside Hogwarts (just in case anything happened to him), walked for a further hour, then returned to his original location exactly one hour after he'd left and spun the Time-Turner again -

"What was that?" Professor Quirrell said, blinking. "Did you just -"

"Nothing important," Harry said without pulling back the hood of his invisibility cloak, or taking his hand from his Time-Turner. "Yes, I'm still resolved. To be honest, I'm thinking I shouldn't have said anything."

Professor Quirrell inclined his head. "A sentiment which shall serve you well in life. Is there anything which is liable to change your mind?"

"Professor, if I already knew about the existence of an argument which would change my decision -"

"True, for the likes of us. But you would be surprised how often someone knows what they are waiting to hear, yet must wait to hear it said." Professor Quirrell shook his head. "To put this in your terms... there is a true fact, known to me but not to you, of which I would like to convince you, Mr. Potter."

Harry's eyebrows rose, though he realized in the next moment that Professor Quirrell couldn't see it. "That's in my terms, all right. Go ahead."

"The intention you have formed is far more dangerous than you realize."

Replying to this surprising statement did not take much thought on Harry's part. "Define dangerous, and tell me what you think you know and how you think you know it."

"Sometimes," said Professor Quirrell, "telling someone about a danger can cause them to walk directly into it. I have no intention of having that happen this time. Do you expect me to tell you exactly what you must not do? Exactly why I am afraid?" The man shook his head. "If you were wizardborn, Mr. Potter, you would know to take it seriously, when a powerful magus tells you only to beware."

It would have been a lie to say that Harry was not annoyed, but he also wasn't an idiot; so Harry said merely, "Is there anything you can tell me?"

Carefully, Professor Quirrell seated himself upon the grass, and took out his wand, his hand assuming a position that Harry recognized. Harry's breath caught.

"This is the last time that I shall be able to do this for you," Professor Quirrell said quietly. Then the man began to speak words that were strange, of no language Harry could recognize, intonation that seemed not quite human, words which seemed to slip from Harry's memory even as he tried to grasp them, exiting from his mind as quickly as they entered.