Harry Potter and the Methods of Rationality (139 page)

Twenty seconds later - it hadn’t been a long chase, just an
exciting
one - Neville was back among his fellow Chaotics, and dismounted his broom to walk on the ground for a little bit.

“Neville -” said General Potter. Harry’s voice was a little distant, as he walked carefully and steadily through the forest, his wand still applied to the almost-finished Form of the object he was slowly Transfiguring. Beside him, Blaise Zabini, working a smaller version of the same Transfiguration, looked like a shambling Inferi as he stumbled forward. “I told you - Neville - you don’t have to -”

“Yes, I do,” said Neville. He looked down at where his fingers grasped the broomstick, and saw that not just his hands, but his whole arms were shaking. But unless anyone else in Chaos had been practicing dueling for an hour a day with Mr. Diggory, and then practicing their aim in private for another hour afterward, Neville was probably the best shot from a broomstick even after taking into account that he wasn’t a very good flyer.

“Good show, Neville,” Theodore said from where he was walking ahead of them all, leading the Chaos Legion forward through the forest while wearing only his undershirt.

(Augusta Longbottom and Charles Nott exchanged brief astonished glances and then wrenched their gazes away from one another as though stung.)

Neville took a few deep breaths, trying to steady his hands, trying to think; Harry might not be good for deep strategic thinking while he was in the middle of an extended Transfiguration. “Lieutenant Nott, do you have any idea why Dragon Army just did that? They lost a broom -” The Dragons had started the combat with a feint to provide a distraction for Mr. Goyle’s approach through the forest; Neville hadn’t realized there were
two
brooms attacking until almost too late. But the Chaos Legion had
gotten
the other pilot. That was why broomsticks usually didn’t attack before armies met, it meant a whole army would concentrate fire on the broomstick. “And the Dragons didn’t even get anyone, did they?”

“Nope!” Tracey Davis said proudly. She too was now marching by General Potter’s side, her wand gripped low and watchful as her eyes scanned the surrounding forest. “I threw up a Prismatic Sphere like a split second before Mr. Goyle’s hex got Zabini, and the way Mr. Goyle had his other arm stretched out I think he planned to knock down the General, too.” The Slytherin witch smiled with vicious confidence. “Mr. Goyle tried a Breaking Drill Hex, but learned to his dismay that his weak magic was no match for my newfound dark powers, hahahaha!”

Some Chaotics laughed with her, but a queasy sensation was starting in Neville’s stomach as he realized how close the Chaos Legion had come to complete disaster. If Mr. Goyle had managed to disrupt both Transfigurations -

“Report!” snapped the Dragon General, doing his best to conceal the fatigue he felt after casting seventeen Locking Charms, with more yet to come.

Beads of sweat now dotted Gregory’s forehead. “The enemy got Dylan Vaughan,” Gregory said formally. “Harry Potter and Blaise Zabini were each Transfiguring something dark-grey and roundish, I don’t think it was finished but it looked like it would be big and hollow, sort of cauldron-shaped. Zabini’s was smaller than Potter’s. I couldn’t get either of them or disrupt their Transfigurations, Tracey Davis blocked me. Neville Longbottom is on a broomstick and he’s still a terrible flyer but his aim is really good.”

Draco listened, frowning, and then he glanced at Padma and Dean Thomas, who both shook their own heads, indicating that they also couldn’t think of what might be big and grey and shaped like a cauldron.

“Anything else?” said Draco. If that was it, they’d lost a broom for nothing -

“The only other weird thing I saw,” Gregory said, sounding puzzled, “was that some Chaotics were wearing… sort of like goggles?”

Draco thought about this, not noticing that he’d stopped marching or that all of Dragon Army had automatically stopped with him.

“Was there anything special about the goggles?” Draco said.

“Um…” Gregory said. “They were… greenish, maybe?”

“Okay,” said Draco. Again without thinking, he began walking once more and his Dragons followed. “Here’s our new strategy. We’re only going to send eleven Dragons against the Chaos Legion, not fourteen. That should be enough to beat them, now that we can neutralize their special advantage.” It was a gamble, but you had to take gambles sometimes, if you wanted to come in first in a three-way battle.

“You figured out Chaos’s plan, General Malfoy?” said Mr. Thomas with considerable surprise.

“What are they doing?” said Padma.

“I haven’t the faintest idea,” said Draco, with a smirk of the most refined smugness. “We’ll just do the obvious thing.”

Harry, having now finished his cauldron, was carefully scooping acorns into the container while the scouts searched for a nearby source of water that could be used as a liquid base. They’d come across frequent sinkholes and miniature creeks in the forest before, so it ought not to take long. Another scout had brought a straight stick that would serve as a stirrer, so Harry didn’t have to Transfigure one.

Sometimes, even though you were looking straight at something, you didn’t realize
what
you were looking at until you happened to ask exactly the right question…

How can I invoke magical powers that ought to be beyond the reach of first-year students?

There was a cautionary tale the Potions Master had told them (with much sneers and laughter to make the stupidity seem low-status instead of daring and romantic) about a second-year witch in Beauxbatons who’d stolen some extremely restricted and expensive ingredients, and tried to brew Polyjuiceso she could borrow the form of another girl for purposes better left unmentioned. Only she’d managed to contaminate the potion with
cat hairs,
and then instead of seeking a healer immediately, the witch had hidden herself in a bathroom, hoping the effects would just wear off; and when she’d finally been found, it had been too late to reverse the transformation completely, condemning her to a life of despair as a sort of cat-girl hybrid.

Harry hadn’t realized what that
meant
until the instant of thinking the right question - but what that implied was that a young wizard or witch could do things with Potions-Making that they couldn’t even come close to doing with Charms. Polyjuice was one of the most potent potions known… but what made Polyjuice a N.E.W.T.-level potion, apparently, wasn’t the required age before you had enough magical power; it was how difficult the potion was to brew precisely and what happened to you if you screwed up.

Nobody in any army had tried brewing any potions up until then. But Professor Quirrell would let you get away with nearly anything, if it was something you could also have done in a real war.
Cheating is technique,
the Defense Professor had once lectured them.
Or rather, cheating is what the losers call technique, and will be worth extra Quirrell points when executed successfully.
In principle, there was nothing unrealistic about Transfiguring a couple of cauldrons and brewing potions out of whatever came to hand, if you had enough time before the armies met.

So Harry had retrieved his copy of
Magical Drafts and Potions,
and begun looking for a safe but useful potion he could brew in the minutes before the battle started - a potion which would win the battle too fast for counterspells, or produce spell effects too strong for first-years to
Finite.

Sometimes, even though you were looking straight at something, you didn’t realize
what
you were looking at until you happened to ask exactly the right question…

What potion can I brew using only components gathered from an ordinary forest?

Every recipe in
Magical Drafts and Potions
used at least one ingredient from a magical plant or animal. Which was unfortunate, because all the
magical
plants and animals were in the Forbidden Forest, not the safer and lesser woods where battles were held.

Someone else might have given up at that point.

Harry had turned the pages from one recipe to another, skimming faster and faster in dawning realization, confirming what he had already read and was now
seeing
for the first time.

Every single Potions recipe seemed to demand at least one magical ingredient,
but why should that be true?

Charms required no material components at all; you just said the words and waved your wand. Harry had been thinking about Potions-Making as essentially analogous: Instead of your spoken syllables triggering a spell effect for no comprehensible reason, you collected a batch of disgusting ingredients and stirred four times clockwise, and that arbitrarily triggered a spell effect.

In which case, given that most potions used ordinary components like porcupine quills or stewed slugs, you’d expect to see some potions using
only
ordinary components.

But instead every single recipe in
Magical Drafts and Potions
demanded at least
one
component from a magical plant or animal - an ingredient like silk from an Acromantula or petals from a Venus Fire Trap.

Sometimes, even though you were looking straight at something, you didn’t realize
what
you were looking at until you happened to ask exactly the right question…

If making a potion is like casting a Charm, why don’t I fall over from exhaustion after brewing a draught as powerful as boil-curing?

The Friday before last, Harry’s double Potions class had brewed
potion of boil-curing…
although even the most trivial healing Charms, if you tried to cast them with wand and incantation, were at least fourth-year spells. And afterward, they’d all felt the way they usually felt after Potions class, namely,
not
magically exhausted to any discernible degree.

Harry had shut his copy of
Magical Drafts and Potions
with a snap, and rushed down to the Ravenclaw common room. Harry had found a seventh-year Ravenclaw doing his N.E.W.T. potions homework and paid the older boy a Sickle to borrow
Moste Potente Potions
for five minutes; because Harry hadn’t wanted to run all the way to the library to find confirmation.

After skimming through five recipes in the seventh-year book, Harry had read the sixth recipe, for a
potion of fire breathing
, which required Ashwinder eggs… and the book warned that the resulting fire could be no hotter than the magical fire which had spawned the Ashwinder which had laid the eggs.

Harry had shouted “
Eureka!
” right in the middle of the Ravenclaw common room, and been severely rebuked by a nearby prefect, who’d thought Mr. Potter was trying to cast a spell. Nobody in the wizarding world knew or cared about some ancient Muggle named Archimedes, nor the ur-physicist’s realization that the water displaced from a bathtub would equal the volume of the object entering the bathtub…

Conservation laws. They’d been the critical insight in more Muggle discoveries than Harry could easily count. In Muggle technology you couldn’t raise a feather one meter off the ground without the power coming from
somewhere.
If you looked at molten lava spilling from a volcano and asked where the heat came from, a physicist would tell you about radioactive heavy metals in the center of the Earth’s molten core. If you asked where the energy to power the radioactivity came from, the physicist would point to an era before the Earth had formed, and a primordial supernova in the early days of the galaxy which had baked atomic nuclei heavier than the natural limit, the supernova compressing protons and neutrons into a tight unstable package that yielded back some of the supernova’s energy when it split. A light bulb was fueled by electricity, fueled by a nuclear power plant, fueled by a supernova… You could play the game all the way back to the Big Bang.

Magic did
not
appear to work like this, to put it mildly. Magic’s attitude toward laws like Conservation of Energy was somewhere between a giant extended middle finger, and a shrug of total indifference.
Aguamenti
created water out of nothingness, so far as anyone knew; there was no known lake whose water level went down each time. That was a simple fifth-year spell, not considered impressive by wizards, because creating a mere glass of water didn’t seem amazing to them. They didn’t have the wacky notion that mass ought to be conserved, or that creating a gram of mass was somehow equivalent to creating 90,000,000,000,000 joules of energy. There was an upper-year spell Harry had run across whose
literal incantation
was ‘
Arresto Momentum!’
and when Harry had asked if the momentum went anywhere
else
he’d just gotten a puzzled look. Harry had kept an increasingly desperate eye out for
some
kind of conservation principle in magic, anywhere whatsoever…

…and the whole time it had been right in front of him in every Potions class. Potions-Making didn’t
create
magic, it
preserved
magic, that was why every potion needed at least one magical ingredient. And by following instructions like ‘stir four times counterclockwise and once clockwise’ - Harry had hypothesized - you were doing something like casting a small spell that reshaped the magic in the ingredients. (And unbound the physical form so that ingredients like porcupine quills dissolved smoothly into a drinkable liquid; Harry strongly suspected that a Muggle following exactly the same recipe would end up with nothing but a spiny mess.) That was what Potions-Making really
was,
the art of transforming existing magical essences. So you were a little tired after Potions class, but not much, because you weren’t empowering the potions yourself, you were just reshaping magic that was already there. And that was why a second-year witch could brew Polyjuice, or at least get close.

Harry had kept scanning through
Moste Potente Potions,
looking for something that might disprove his shiny new theory. After five minutes he’d flipped the older boy another Sickle (over his protests) and kept going.