Harry Potter and the Methods of Rationality

"Yes, an otter," said Hermione. "What about yours?"

"Peregrine falcon," Harry said without hesitation. "It can dive faster than three hundred kilometers per hour, it's the fastest living creature there is." The peregrine falcon had been Harry's favorite animal since forever. Harry was determined to become an Animagus someday, just to get that as his form, and fly by the strength of his own wings, and see the land below with sharper eyes... "But why an otter?"

Hermione smiled, but didn't say anything.

And the vast doors of Hogwarts swung open.

They walked for a time, the children, over a pathway that led toward the unforbidden forest, and continued through the forest itself. The Sun was lowering to near the horizon, the shadows long, the sunlight filtered through the bare branches of the winter trees; for it was January, and the first-years the last to learn, that day.

Then the path swerved and took a new direction, and they all saw it in the distance, the clearing in the forest, and the sere winter grounds, yellowing dried grass whitened by a few small remnants of snow.

The human figures still small at that range. The two spots of dim white light from the Aurors' Patronuses, and the brighter spot of silver light from the Headmaster's, next to something...

Harry squinted.

Something...

It must have been purely Harry's imagination, because there shouldn't have been any way for a Dementor to reach past three corporeal Patronuses, but he thought he could feel a touch of emptiness brushing at his mind, brushing straight at the soft inner center of himself without any respect for Occlumency barriers.

Seamus Finnigan was ashen and trembling as he rejoined the students milling about on the withered and snow-spotted grass. Seamus's Patronus Charm had been successful, but there was still that interval between when the Headmaster dispelled his own Patronus and when you were supposed to cast your own, when you faced the Dementor's fear unshielded.

Up to twenty seconds of exposure at five paces was certainly safe, even for an eleven-year-old wizard with weak resistance and a still-maturing brain. There was a lot of variance in how hard the Dementor's power hit people, which was another thing not quite understood; but twenty seconds was definitely safe.

Forty seconds of Dementor exposure at five paces might possibly have been enough to cause permanent damage, though only to the most sensitive subjects.

It was harsh training even by the standards of Hogwarts, where the way you learned to fly on a hippogriff was by being tossed on one and told to get going. Harry was no fan of overprotectiveness, and if you looked at the difference in maturity between a fourth-year in Hogwarts and a fourteen-year-old Muggle, it was clear that Muggles were smothering their children... but even Harry had started to wonder if this was pushing it. Not every hurt could be healed afterward.

But if you couldn't cast the spell under those conditions, it meant you couldn't rely on using the Patronus Charm to defend yourself; overconfidence was even more dangerous to wizards than to Muggles. Dementors could drain your magic and your physical vitality, not just your happy thoughts, which meant you might not be able to Apparate away if you waited too long, or if you didn't recognize the approaching fear until the Dementor was within range for its attack. (During his reading, Harry had discovered with considerable horror that some books claimed the Dementor's Kiss would eat your soul and that this was the reason for the permanent mindless coma into which it put the victims. And that wizards who believed this had deliberately used the Dementor's Kiss to execute criminals. It was a certainty that some called criminals were innocent, and even if they weren't, destroying their souls? If Harry had believed in souls, he would have... drawn a blank, he just couldn't think of an appropriate response to that.)

The Headmaster was taking security seriously, and so were the three Aurors standing guard. Their leader was an Asianish-looking man, solemn without being grim, Auror Komodo, whose wand never left his hand. His Patronus, an orangutan of solid moonlight, paced back and forth between the Dementor and the first-years awaiting their turn; beside the orangutan moved the bright white panther of Auror Butnaru, a man with a piercing gaze, long black hair in a ponytail, and a long braided goatee. Those two Aurors, and their two Patronuses, were all watching the Dementor. On the opposite side of the students was the resting Auror Goryanof, tall and thin and pale and unshaven, sitting back on a chair he'd conjured without word or wand, and maintaining an absentminded pokerface as he scanned the entire scene. Professor Quirrell had shown up not long after the first-years began their attempts, and his eyes never strayed far from Harry. The tiny Professor Flitwick, who had been a champion duellist, was fiddling absently with his wand; and his eyes, peering out from within the huge puffy beard that served as his face, stayed focused on Professor Quirrell.

And it must have been Harry's imagination, but Professor Quirrell seemed to wince slightly each time the Headmaster's Patronus winked out to test the next student. Maybe Professor Quirrell was imagining the same placebo effect as Harry, that backwash of emptiness caressing at his mind.

"Anthony Goldstein," called the voice of the Headmaster.

Harry quietly walked toward Seamus, even as Anthony began to approach the shining silver phoenix, and... whatever it was beneath the tattered cloak.

"What did you see?" Harry asked Seamus in a low voice.

A lot of students hadn't answered Harry, when he'd tried to gather the data; but Seamus was Finnigan of Chaos, one of Harry's lieutenants. Maybe that wasn't fair, but...

"Dead," said Seamus in a whisper, "grayish and slimy... dead and left in water for a while... "

Harry nodded. "That's what a lot of people see," Harry said. He projected confidence, even though it was fake, because Seamus needed it. "Go eat some chocolate, you'll feel better."

Seamus nodded and stumbled off toward the table of healing sweets.

"Expecto Patronum!" cried a young boy's voice.

Then there were gasps of shock, even from the Aurors.

Harry spun around to look -

There was a brilliant silver bird standing between Anthony Goldstein and the cage. The bird reared its head and let out a cry, and the cry was also silver, as bright and hard and beautiful as metal.