Harry Potter and the Methods of Rationality

Professor Quirrell gave the DMLE Director a half-nod of acknowledgment. "As you say, Madam Bones. Mr. Malfoy is new to the business of having ideas, and so when he has one, he becomes proud of himself for having it. He has not yet had enough ideas to unflinchingly discard those that are beautiful in some aspects and impractical in others; he has not yet acquired confidence in his own ability to think of better ideas as he requires them. What we are seeing here is not Mr. Malfoy's best idea, I fear, but rather his only idea."

Lord Malfoy simply turned to watch the screens again, as though the Defense Professor had used up his right to exist.

"But -" said Lord Greengrass. "But what in Merlin's name is Harry Potter -"

Sixteen remaining soldiers of the Chaos Legion - or fifteen plus Blaise Zabini, rather - marched confidently through the forest, their shoes thudding over the still-dry ground. Their camouflage uniforms blended into the forest even more than usual, all colors washed out by the tints of an overcast day.

Sixteen Chaos Legionnaires, against twenty-eight Dragon Warriors and twenty-eight Sunshine Soldiers.

The common consensus had been that, with odds that bad, it was practically impossible for them to lose. After all, General Chaos was bound to come up with something really spectacular, facing odds like that.

There was something almost nightmarish about how everyone seemed to now expect Harry to pull miracles out of his hat, on demand, any time one was needed. It meant that if you couldn't do the impossible, you were disappointing your friends and failing to live up to your potential...

Harry hadn't bothered complaining to Professor Quirrell about 'too much pressure'. Harry's mental model of the Defense Professor had predicted him looking severely annoyed, saying things along the lines of You are perfectly capable of solving this problem, Mr. Potter; did you even try? and then deducting several hundred Quirrell points.

From above, from where two broomsticks watched their march, the high young voice of Tess Walsh cried "Friend!" and after another moment, "Gingersnap!"

A handful of seconds later, the soldier who'd code-named herself Gingersnap returned bearing a double handful of acorns, sweating slightly in the cool but humid air from the jog that had taken her to the oak tree Neville had spotted. Gingersnap approached to where Shannon was holding a uniform-shirt with the neck tied off, in lieu of anyone having to Transfigure a bag. When Gingersnap brought her hands forward to try and dump her acorns into the holding-shirt, Chaotic Shannon, giggling, jerked the shirt to the right, then to the left again as Gingersnap made another effort to dump the acorns, until a sharp "Miss Friedman!" from Lieutenant Nott caused Shannon to sigh and hold the shirt still. Gingersnap dumped her acorns into those accumulated, and then headed out for more.

Somewhere in the background, Ellie Knight was singing her very own version of the Chaos Legion's marching song, and around half the other soldiers were trying to step along with it despite not knowing the tune in advance. Nearby, Nita Berdine, who had a high Transfiguration score, finished creating yet another pair of green sunglasses, and handed them to Adam Beringer, who folded up the sunglasses before tucking them into his uniform pocket. Other soldiers were already wearing their own green sunglasses, despite the cloudy day.

You might guess that there was some sort of incredibly complicated and fascinating explanation behind this, and you would be right.

Two days earlier Harry had been sitting amid his bookcases in the comfy rocking-chair he'd obtained for his trunk's cavern level, pondering silently in the quiet span between classes and dinnertime, thinking about power.

For sixteen Chaotics to defeat twenty-eight Sunnies and twenty-eight Dragons they would need a force amplifier. There were limits to what you could do with maneuver. There had to be a secret weapon and it had to be invincible, or at least moderately unstoppable.

Muggle artifacts were now illegal in Hogwarts's mock battles, banned by Ministry edict. And the trouble with finding some other clever and unusual spell was that an army twice your own size could brute-force Finite almost anything you tried. The Sunshine Regiment might have missed that tactic with the Transfigured chainmail, but nobody would miss it again now that Professor Quirrell had spelled it out. And Finite Incantatem was a brute-force counterspell which required at least as much magic as the spell being canceled... which, if you were severely outnumbered, made it a whole new order of military challenge. The enemy could Finite anything you tried, and still have enough magic left over for shields and volleys of Sleep Hexes.