Harry Potter and the Methods of Rationality

"EXPECTO PATRONUM!"

The thought exploded from him like a breaking dam, surged down his arm into his wand, burst from it as blazing white light. Light that became corporeal, took on shape and substance.

A figure with two arms, two legs, and a head, standing upright; the animal Homo sapiens, the shape of a human being.

Glowing brighter and brighter as Harry poured all his strength into his spell, blazing with incandescent light brighter than the fading sunset, the Aurors and Professor Quirrell shielding their eyes in shock -

And someday when the descendants of humanity have spread from star to star, they won't tell the children about the history of Ancient Earth until they're old enough to bear it; and when they learn they'll weep to hear that such a thing as Death had ever once existed!

The figure of a human shone more brilliant now than the noonday Sun, so radiant that Harry could feel the warmth of it on his skin; and Harry sent out all his defiance at the shadow of Death, opening all the floodgates inside him to make that bright shape blaze even brighter and yet brighter.

You are not invincible, and someday the human species will end you.

I will end you if I can, by the power of mind and magic and science.

I won't cower in fear of Death, not while I have a chance of winning.

I won't let Death touch me, I won't let Death touch the ones I love.

And even if you do end me before I end you,

Another will take my place, and another,

Until the wound in the world is healed at last...

Harry lowered his wand, and the bright figure of a human faded away.

Slowly, he exhaled.

Like waking up from a dream, like opening his eyes after sleep, Harry's gaze moved away from the cage, he looked around and saw that everyone was staring at him.

Albus Dumbledore was staring at him.

Professor Quirrell was staring at him.

The Auror trio was staring at him.

They were all looking at him like they'd just seen him destroy a Dementor.

The tattered cloak lay empty within the cage.

Chapter 46: Humanism, Pt 4

The last tip of the Sun was sinking below the horizon, the red light fading from the treetops, only the blue sky illuminating the six people standing upon the winter-dried and snow-spotted grass, near a vacant cage on whose floor lay an empty, tattered cloak.

Harry felt... well, normal again. Sane-ish. The spell hadn't undone the day and its damage, hadn't made the injuries as if they had never been, but his hurts had been... bandaged, meliorated? It was hard to describe.

Dumbledore was also looking healthier, though not fully restored. The old wizard's head turned for a moment, locked eyes with Professor Quirrell, then looked back to Harry. "Harry," Dumbledore said, "are you about to collapse in exhaustion and possibly die?"

"No, strangely enough," Harry said. "That took something out of me, but a lot less than I thought it would." Or maybe it gave something back, as well as taking... "Honestly, I expected my body to be hitting the ground with a thud about now."

There was a distinct body-hitting-the-ground-with-a-thuddish sort of sound.

"Thank you for taking care of that, Quirinus," said Dumbledore to Professor Quirrell, who was now standing above and behind the unconscious forms of the three Aurors. "I confess I am still feeling a bit peaky. Though I shall handle the Memory Charms myself."

Professor Quirrell inclined his head, and then looked at Harry. "I will omit a good deal of useless incredulity," said Professor Quirrell, "remarks to the effect that Merlin himself failed to do that, et cetera. Let us go straight to asking the important question. What the sweet slithering snakes was that?"

"The Patronus Charm," Harry said. "Version 2.0."

"I rejoice to see that you are your usual self again," said Dumbledore. "But you are not going anywhere, young Ravenclaw, until you tell me what exactly was that warm and happy thought."

"Hm..." said Harry. He tapped a contemplative finger on his cheek. "I wonder if I should?"

Professor Quirrell suddenly grinned.

"Please?" said the Headmaster. "Pretty please with sugar on top?"

Harry felt an impulse and decided to go with it. It was dangerous, but there might not ever be a better opportunity until the end of time.

"Three sodas," Harry said to his pouch, then looked up at the Defense Professor and the Headmaster of Hogwarts. "Gentlemen," Harry said, "I bought these sodas on my first visit to Platform Nine and Three-Quarters, on the day I entered into Hogwarts. I have been saving them for special occasions; there is a minor enchantment on