Harry Potter and the Methods of Rationality

Thoughts came to Harry's mind, then, elements of the vast stored wisdom and the thousand other lives that lay within his parents' science fiction collection. There might be other reasons why Harry sometimes seemed older than his physical age, but all those fictional lives he'd lived had probably also played a role. Harry might not be able to remember the exact words, like Hermione could, but he remembered the sense.

In the mirrors of the many judgments, my hands are the color of blood. I sometimes fancy myself an evil which exists to oppose other evils; and on that great Day of which the prophets speak but in which they do not truly believe, on the day the world is utterly cleansed of evil, then I too will go down into darkness, swallowing curses. Until then, I will not wash my hands nor let them hang useless.

Corwin of Amber.

There will always be some that cannot be saved.

If I must sacrifice five hundred to save one thousand -

Then I will abandon one hundred and earn nine hundred.

But still -

I believed someone would be a superhero if they saved everyone even though they thought like that.

It might be an idealistic concept or an impossible pipe dream, but a superhero is someone who tries to save everyone in spite of that.

Emiya Shirou.

No words can prevent all killing. Words are not iron bands. But I taught you to hesitate, to stay your hands until the weight of duty crushed them down.

Anansi the Spider.

Harry took in a breath of the cold night air, and said, quietly into the night, "All right."

Slowly - he'd probably been lying there, looking at the stars, for longer than he'd thought - Harry sat up from the ground. Pushing himself to his feet, the muscles protesting, he walked over to the edge of the stone platform at the height of the Ravenclaw tower. The stone crenellations surrounding the edge of the tower weren't high, not anywhere near high enough to be safe; they were there more as a marker, clearly, than as a railing. Harry didn't approach too close to the edge; there was no point in taking chances. Looking down at the Hogwarts grounds below, he was predictably feeling a sense of dizziness, the wobbly affliction called vertigo. His brain was alarmed, of course, because the ground below was so distant. It might have been fully 50 meters away.

I will make a bargain with myself, Harry said to within himself, to all his parts. I will follow the path of the superhero as far as I can. But if I can't - if anyone dies, not just an Important Character like Hermione or Professor McGonagall but a single nameless innocent bystander who catches a Cutting Curse - then the gloves come off and the villains die as fast as possible; and I won't pretend that real people in real life can go through a war without sacrificing anyone...

...if I fail.

I'll try as hard as I can to save everyone, but if I fail, I'll admit it didn't work, and change policies. Does that satisfy us?

It didn't, really; it didn't satisfy any part of him; Slytherin who was afraid they would lose the war trying to act like a superhero even once, Gryffindor who wanted more than one try.

But all Harry's parts understood that compromises had to be made, and that this was the best compromise they were collectively likely to get; and besides, in the end, Harry himself had the final word.

Turning resolutely upon his heel, the boy strode back toward the gap in the rooftop that was the stairway leading down into the Ravenclaw tower. In the end...