Harry Potter and the Methods of Rationality

...

If I solve this one, said Harry's brain, I want a cookie afterward, and if you make the problem any more difficult than this, I mean the slightest bit more difficult, I am climbing out of your skull and heading for Tahiti.

Harry and his brain considered the problem.

Azkaban had stood invincible for centuries, relying upon the impossibility of evading the Dementors' gaze. So if Harry found another way to hide Bellatrix from the Dementors, it would rely on either his scientific knowledge or his realization that the Dementors were Death.

Harry's brain suggested that an obvious way to stop the Dementors from seeing Bellatrix was to make her stop existing, i.e., kill her.

Harry congratulated his brain on thinking outside the box and told it to continue searching.

Kill her and then bring her back, came the next suggestion. Use Frigideiro to cool Bellatrix down to the point where her brain activity stops, then warm her up afterward using Thermos, just like people who fall into very cold water can be successfully revived half-an-hour later without noticeable brain damage.

Harry considered this. Bellatrix might not survive in her debilitated state. And it might not stop Death from seeing her. And he'd have trouble carrying a cold unconscious Bellatrix very far. And Harry couldn't remember the research on which exact body temperature was supposed to be nonfatal but temporarily-brain-halting.

It was another good outside-the-box idea, but Harry told his brain to keep thinking of...

...ways to hide from Death...

A frown moved over Harry's face. He'd heard something about that, somewhere.

One of the requisites for becoming a powerful wizard is an excellent memory, Professor Quirrell had said. The key to a puzzle is often something you read twenty years ago in an old scroll, or a peculiar ring you saw on the finger of a man you met only once...

Harry focused as hard as he could, but he couldn't remember, it was on the tip of his tongue but he couldn't remember; so he told his subconscious to go on trying to recollect it, and refocused his attention on the other half of the problem.

How can I protect myself from the Dementors without a Patronus Charm?

The Headmaster had been repeatedly exposed to a Dementor from a few steps away, over and over throughout a whole day, and had come out of it looking merely tired. How had the Headmaster done that? Could Harry do it too?

It could just be some random genetic thing, in which case Harry was screwed. But assuming the problem was solvable...

Then the obvious answer was that Dumbledore wasn't afraid of death.

Dumbledore really wasn't afraid of death. Dumbledore honestly, truly believed that death was the next great adventure. Believed it in his core, not just as convenient words used to suppress cognitive dissonance, not just pretending to be wise. Dumbledore had decided that death was the natural and normative order, and whatever tiny lingering fear was still in him, it had taken a long time and repeated exposures for the Dementor to drain him through that small flaw.

That avenue was closed to Harry.

And then Harry thought of the flip side, the obvious inverse question:

Why am I so much more vulnerable than average? Other students didn't fall over when they faced the Dementor.

Harry meant to destroy Death, to end it if he could. He meant to live forever, if he could; he had hope of it, the thought of Death brought him no sense of despair or inevitability. He was not blindly attached to his own life; indeed it had taken an effort not to burn away all his life on the need to protect others from Death. Why did the shadows of Death have such power over Harry? He would not have thought himself so afraid.

Was it Harry, all along, who'd been rationalizing? Who was secretly so afraid of death that it was twisting his own thoughts, as Harry had accused Dumbledore?

Harry considered this, preventing himself from flinching away. It felt uncomfortable, but...

But...

But uncomfortable thoughts weren't always true, and this one didn't sound exactly right. Like there was a grain of truth, but it wasn't hiding where the hypothesis said it was -

And that was when Harry realized.

Oh.

Oh, I understand now.

The one who is afraid, is...

Harry asked his dark side what it thought of death.

And Harry's Patronus wavered, dimmed, almost went out upon the instant, for that desperate, sobbing, screaming terror, an unutterable fear that would do anything not to die, throw everything aside not to die, that couldn't think straight or feel straight in the presence of that absolute horror, that couldn't look into the abyss of nonexistence any more than it could have stared straight into the Sun, a blind terrified thing that only wanted to find a dark corner and hide and not have to think about it any more -

The silver figure had darkened to moonlight, was flickering like a failing candle -