Harry Potter and the Methods of Rationality (46 page)

If you were Harry’s enemy, his plots might be hard to see through at first, they might even be stupid, but his reasoning would make
sense
once you understood it, you would comprehend that he was trying to hurt you.

The way Harry was acting toward Draco right now did
not
make sense.

Because if you were Harry’s
friend,
then he tried to be friends with you in the alien, incomprehensible way he’d been raised by Muggles to do, even if it meant destroying your entire life.

The silence stretched.

“I know that I’ve abused our friendship terribly,” Harry said finally. “But please realize, Draco, that in the end, I just wanted the two of us to find the truth together. Is that something you can forgive?”

A fork with two paths, but with only one path easy to go back on later if Draco changed his mind…

“I guess I understand what you were trying to do,” Draco lied, “so yes.”

Harry’s eyes lit up. “I’m glad to hear that, Draco,” he said softly.

The two students stood in that alcove, Harry still dipped in the lone sunbeam, Draco in shadow.

And Draco realized with a note of horror and despair, that although it was a terrifying fate indeed to be Harry’s friend, Harry now had so many different avenues for threatening Draco that being his enemy would be even
worse
.

Probably.

Maybe.

Well, he could always switch to being enemies later…

He was doomed.

“So,” Draco said. “Now what?”

“We study again next Saturday?”

“It better not go like the last one -”

“Don’t worry, it won’t,” said Harry. “A few more Saturdays like
that
and you’d be ahead of
me.
”

Harry laughed. Draco didn’t.

“Oh, and before you go,” Harry said, and grinned sheepishly. “I know this is a bad time, but I wanted to ask you for advice about something, actually.”

“Okay,” Draco said, still a bit distracted by that last statement.

Harry’s eyes grew intent. “Buying that pouch for Granger used up most of the gold I managed to steal from my Gringotts vault -”

What.

“- and McGonagall has the vault key, or Dumbledore does now, maybe. And I was just about to launch a plot that might take some money, so I was wondering if you know how I can get access -”

“I’ll loan you the money,” said Draco’s mouth in sheer existential reflex.

Harry looked taken aback, but in a pleased way. “Draco, you don’t have to -”

“How much?”

Harry named the amount and Draco couldn’t quite keep the shock from showing on his face. That was almost all the spending money Father had given Draco to last out the whole year, Draco would be left with just a few Galleons -

Then Draco mentally kicked himself. All he had to do was write Father and explain that the money was gone because he had managed to
loan it to Harry Potter,
and Father would send him a special congratulatory note written in golden ink, a giant Chocolate Frog that would take two weeks to eat, and ten times as many Galleons just in case Harry Potter needed another loan.

“It’s way too much, isn’t it,” said Harry. “I’m sorry, I shouldn’t have asked -”

“Excuse me, I
am
a Malfoy, you know,” said Draco. “I was just surprised you
wanted
that much.”

“Don’t worry,” Harry Potter said cheerfully. “It’s nothing that threatens your family’s interests, just me being evil.”

Draco nodded. “No problem, then. You want to go get it right now?”

“Sure,” said Harry.

As they left the alcove and started heading toward the dungeons, Draco couldn’t help but ask, “So
can
you tell me which plot this is for?”

“Rita Skeeter.”

Draco thought some very bad words to himself, but it was far too late to say no.

By the time they’d reached the dungeons, Draco had started pulling together his thoughts again.

He
was
having trouble hating Harry Potter. Harry
had
been trying to be friendly, he was just insane.

And that wasn’t going to stop Draco’s revenge or even slow it down.

“So,” Draco said, after looking around to make certain no one was nearby. Their voices would both be Blurred, of course, but it never hurt to be extra sure. “I’ve been thinking. When we bring new recruits into the Conspiracy, they’re going to have to
think
we’re equals. Otherwise it would only take
one
of them to blow the plot to Father. You already worked that out, right?”

“Naturally,” said Harry.

“
Will
we be equals?” said Draco.

“I’m afraid not,” Harry said. It was clear that he was trying to sound gentle, and also clear that he was trying to suppress a good deal of condescension and not quite succeeding. “I’m sorry, Draco, but you don’t even know what the word
Bayesian
in
Bayesian Conspiracy
means right now. You’re going to have to study for months before we take anyone else in, just so you can put up a
good front
.”

“Because I don’t know enough science,” Draco said, carefully keeping his voice neutral.

Harry shook his head at that. “The problem isn’t that you’re ignorant of specific science things like deoxyribonucleic acid.
That
wouldn’t stop you from being my equal. The problem is that you aren’t trained in the methods of rationality, the
deeper
secret knowledge behind how all those discoveries got made in the first place. I’ll
try
to teach you those, but they’re a lot harder to learn. Think of what we did yesterday, Draco. Yes, you did some of the work. But I was the only one in control. You answered some of the questions. I asked all of them. You helped push. I did the steering by myself. And without the methods of rationality, Draco, you can’t possibly steer the Conspiracy where it needs to go.”

“I see,” said Draco, his voice sounding disappointed.

Harry’s voice tried to gentle itself even more. “I’ll try to respect your expertise, Draco, about things like people stuff. But you need to respect my expertise too, and there’s just no
way
you could be my equal when it comes to steering the Conspiracy. You’ve only been a scientist for
one day
, you know
one
secret about deoxyribonucleic acid, and you aren’t trained in
any
of the methods of rationality.”

“I understand,” said Draco.

And he did.

People stuff,
Harry had said. Seizing control of the Conspiracy probably wouldn’t even be difficult. And afterward, he would kill Harry Potter just to be sure -

The memory rose up in Draco of how sick inside it had felt last night, knowing Harry was screaming.

Draco thought some more bad words.

Fine. He
wouldn’t
kill Harry. Harry had been raised by Muggles, it wasn’t his fault he was insane.

Instead, Harry would live on, just so that Draco could tell him that it had all been for Harry’s own good, really, he ought to be grateful -

And with a sudden twitch of surprised pleasure, Draco realized that it actually
was
for Harry’s own good. If Harry tried to carry out his plan of playing Dumbledore and Father for fools, he would
die.

That made it
perfect.

Draco would take all of Harry’s dreams away from him, just as Harry had done to him.

Draco would tell Harry that it had been for his own good, and it would be absolutely true.

Draco would wield the Conspiracy and the power of science to purify the wizarding world, and Father would be as proud of him as if he’d been a Death Eater.

Harry Potter’s evil plots would be foiled, and the forces of right would prevail.

The perfect revenge.

Unless…

Just pretend to be pretending to be a scientist,
Harry had told him.

Draco didn’t have words to describe exactly what was wrong with Harry’s mind -

(since Draco had never heard the term
depth of recursion
)

- but he could guess what sort of plots it implied.

…unless all that was exactly what Harry
wanted
Draco to do as part of some even
larger
plot which Draco would play
right into
by trying to foil this one, Harry might even
know
that his plan was unworkable, it might have no purpose
except
luring Draco to thwart it -

No. That way lay
madness.
There
had
to be a limit. The Dark Lord himself hadn’t been
that
twisty. That sort of thing didn’t happen in real life, only in Father’s silly bedtime stories about foolish gargoyles who always ended up furthering the hero’s plans every time they tried to stop him.

And beside Draco, Harry walked along with a smile on his face, thinking about the evolutionary origins of human intelligence.

In the beginning, before people had quite understood how evolution worked, they’d gone around thinking crazy ideas like
human intelligence evolved so that we could invent better tools.

The reason why this was crazy was that only one person in the tribe had to invent a tool, and then everyone else would use it, and it would spread to other tribes, and still be used by their descendants a hundred years later. That was great from the perspective of scientific progress, but in evolutionary terms, it meant that the person who invented something didn’t have much of a fitness
advantage
, didn’t have all that many
more
children than everyone else. Only
relative
fitness advantages could increase the relative frequency of a gene in the population, and drive some lonely mutation to the point where it was universal and everyone had it. And brilliant inventions just weren’t common enough to provide the sort of consistent selection pressure it took to promote a mutation. It was a natural guess, if you looked at humans with their guns and tanks and nuclear weapons and compared them to chimpanzees, that the intelligence was there to make the technology. A natural guess, but wrong.

Before people had quite understood how evolution worked, they’d gone around thinking crazy ideas like
the climate changed, and tribes had to migrate, and people had to become smarter in order to solve all the novel problems.

But human beings had four times the brain size of a chimpanzee. 20% of a human’s metabolic energy went into feeding the brain. Humans were
ridiculously
smarter than any other species. That sort of thing didn’t happen because the environment stepped up the difficulty of its problems a little. Then the organisms would just get a little smarter to solve them. Ending up with that gigantic outsized brain must have taken some sort of
runaway
evolutionary process, something that would push and push without limits.

And today’s scientists had a pretty good guess at what that runaway evolutionary process had been.

Harry had once read a famous book called
Chimpanzee Politics.
The book had described how an adult chimpanzee named Luit had confronted the aging alpha, Yeroen, with the help of a young, recently matured chimpanzee named Nikkie. Nikkie had not intervened directly in the fights between Luit and Yeroen, but had prevented Yeroen’s other supporters in the tribe from coming to his aid, distracting them whenever a confrontation developed between Luit and Yeroen. And in time Luit had won, and become the new alpha, with Nikkie as the second most powerful…

…though it hadn’t taken very long after that for Nikkie to form an alliance with the defeated Yeroen, overthrow Luit, and become the
new
new alpha.

It really made you appreciate what millions of years of hominids trying to outwit
each other
- an evolutionary arms race without limit - had led to in the way of increased mental capacity.

‘Cause, y’know, a human would have totally seen that one coming.

And beside Harry, Draco walked along, suppressing his smile as he thought about his revenge.

Someday, maybe in years but someday, Harry Potter would learn just what it meant to underestimate a Malfoy.

Draco had awakened as a scientist in a single day. Harry had said that wasn’t supposed to happen for months.

But of course if you were a Malfoy, you would be a more powerful scientist than anyone who wasn’t.

So Draco would learn all of Harry Potter’s methods of rationality, and then when the time was ripe -

To seek out new life, and J. K. Rowling!

Note: Since the science in this story is usually all correct, I include a warning that in Ch. 22-25 Harry overlooks many possibilities, the most important of which is that there are lots of magical genes but they’re all on one chromosome (which wouldn’t happen naturally, but the chromosome might have been engineered). In this case, the inheritance pattern would be Mendelian, but the magical chromosome could still be degraded by chromosomal crossover with its nonmagical homologue. (Harry has read about Mendel and chromosomes in science history books, but he hasn’t studied enough actual genetics to know about chromosomal crossover. Hey, he’s only eleven.) However, although a modern science journal would find a
lot
more nits to pick, everything Harry presents as strong evidence is in fact strong evidence - the other possibilities are
improbable
.

Act 2:

(The sun shone brilliantly into the Great Hall from the enchanted sky-ceiling above, illuminating the students as though they sat beneath the naked sky, gleaming from their plates and bowls, as, refreshed by a night’s sleep, they inhaled breakfast in preparation for whatever plans they’d made for their Sunday.)

So. There was only one thing that made you a wizard.

That wasn’t surprising, when you thought about it. What DNA mostly did was tell ribosomes how to chain amino acids together into proteins. Conventional physics seemed quite capable of describing amino acids, and no matter how many amino acids you chained together, conventional physics said you would never, ever get magic out of it.

And yet magic seemed to be hereditary, following DNA.

Then that probably
wasn’t
because the DNA was chaining together nonmagical amino acids into magical proteins.

Rather the key DNA sequence did not, of itself, give you your magic at all.

Magic came from somewhere else.

(At the Ravenclaw table there was one boy who was staring off into space, as his right hand automatically spooned some unimportant food into his mouth from whatever was in front of him. You probably could have substituted a pile of dirt and he wouldn’t have noticed.)

And for some reason the Source of Magic was paying attention to a particular DNA marker among individuals who were ordinary ape-descended humans in every other way.

(Actually there were quite a lot of boys and girls staring off into space. It was the
Ravenclaw
table, after all.)

There were other lines of logic leading to the same conclusion.
Complex
machinery was always universal within a sexually reproducing species. If gene B relied on gene A, then A had to be useful on its own, and rise to near-universality in the gene pool on its own, before B would be useful often enough to confer a fitness advantage. Then once B was universal you would get a variant A* that relied on B, and then C that relied on A* and B, then B* that relied on C, until the whole machine would fall apart if you removed a single piece. But it all had to happen
incrementally
- evolution never looked ahead, evolution would never start promoting B in
preparation
for A becoming universal later. Evolution was the simple historical fact that, whichever organisms did in fact have the most children, their genes would in fact be more frequent in the next generation. So each piece of a complex machine had to become nearly universal before other pieces in the machine would evolve to depend on its presence.

So
complex, interdependent
machinery, the powerful sophisticated protein machines that drove life, was always
universal
within a sexually reproducing species - except for a small handful of
non
-interdependent
variants
that were being selected on at any given time, as further complexity was slowly laid down. It was why all human beings had the same underlying brain design, the same emotions, the same facial expressions wired up to those emotions; those adaptations were complex, so they
had
to be universal.

If magic had been like that, a big complex adaptation with lots of necessary genes, then a wizard mating with a Muggle would have resulted in a child with only half those parts and half the machine wouldn’t do much. And so there would have been no Muggleborns, ever. Even if all the pieces had individually gotten into the Muggle gene pool, they’d never reassemble all in one place to form a wizard.

There hadn’t been some genetically isolated valley of humans that had stumbled onto an evolutionary pathway leading to sophisticated magical sections of the brain. That complex genetic machinery, if wizards interbred with Muggles, would never have reassembled into Muggleborns.

So however your genes made you a wizard, it
wasn’t
by containing the blueprints for complicated machinery.

That was the other reason Harry had guessed the Mendelian pattern would be there. If magical genes weren’t complicated, why would there be more than one?

And yet magic itself seemed pretty complicated. A door-locking spell would prevent the door from opening
and
prevent you from Transfiguring the hinges
and
resist
Finite Incantatem
and
Alohomora
. Many elements all pointing in the same direction: you could call that goal-orientation, or in simpler language, purposefulness.

There were only two known causes of purposeful complexity. Natural selection, which produced things like butterflies. And intelligent engineering, which produced things like cars.

Magic didn’t seem like something that had self-replicated into existence. Spells were purposefully complicated, but not, like a butterfly, complicated for the purpose of making copies of themselves. Spells were complicated for the purpose of serving their user, like a car.

Some intelligent engineer, then, had created the Source of Magic, and told it to pay attention to a particular DNA marker.

The obvious next thought was that this had something to do with “Atlantis”.

Harry had asked Hermione about that earlier - on the train to Hogwarts, after hearing Draco say it - and so far as she knew, nothing more was known than the word itself.

It might have been pure legend. But it was also plausible enough that a civilization of magic-users, especially one from
before
the Interdict of Merlin, would have managed to blow itself up.

The line of reasoning continued: Atlantis had been an isolated civilization that had somehow brought into being the Source of Magic, and told it to serve only people with the Atlantean genetic marker, the blood of Atlantis.

And by similar logic: The words a wizard spoke, the wand movements, those weren’t complicated enough of themselves to build up the spell effects from scratch - not the way that the three billion base pairs of human DNA actually
were
complicated enough to build a human body from scratch, not the way that computer programs took up thousands of bytes of data.

So the words and wand movements were just triggers, levers pulled on some hidden and more complex machine. Buttons, not blueprints.

And just like a computer program wouldn’t compile if you made a single spelling error, the Source of Magic wouldn’t respond to you unless you cast your spells in exactly the right way.

The chain of logic was inexorable.

And it led inevitably toward a single final conclusion.

The ancient forebears of the wizards, thousands of years earlier, had told the Source of Magic to only levitate things if you said…

‘Wingardium Leviosa.’

Harry slumped over at the breakfast table, resting his forehead wearily on his right hand.

There was a story from the dawn days of Artificial Intelligence - back when they were just starting out and no one had yet realized the problem would be difficult - about a professor who had delegated one of his grad students to solve the problem of computer vision.

Harry was beginning to understand how that grad student must have felt.

This could take a while.

Why did it take more effort to cast the Alohomora spell, if it was just like pressing a button?

Who’d been silly enough to build in a spell for
Avada Kedavra
that could only be cast using hatred?

Why did wordless Transfiguration require you to make a complete mental separation between the concept of form and concept of material?

Harry might not be done with this problem by the time he graduated Hogwarts. He could still be working on this problem when he was
thirty years old.
Hermione had been right, Harry
hadn’t
realized that on a gut level before. He’d just given an inspiring speech about determination.

Harry’s mind briefly considered whether to get on a gut level that he might never solve the problem at all, then decided that would be taking things much too far.

Besides, so long as he could get as far as immortality in the first few decades, he’d be fine.

What method had the Dark Lord used? Come to think, the fact that the Dark Lord had somehow managed to survive the death of his first body was almost
infinitely
more important than the fact that he’d tried to take over magical Britain -

“Excuse me,” said an expected voice from behind him in very unexpected tones. “At your convenience, Mr. Malfoy requests the favor of a conversation.”

Harry did not choke on his breakfast cereal. Instead he turned around and beheld Mr. Crabbe.

“Excuse
me,
” said Harry. “Don’t you mean ‘Da boss wants ta talk wid youse?’”

Mr. Crabbe didn’t look happy. “Mr. Malfoy instructed me to speak properly.”

“I can’t hear you,” Harry said. “You’re not speaking properly.” He turned back to his bowl of tiny blue crystal snowflakes and deliberately ate another spoonful.

“Da boss wants to talk with youse,” came a threatening voice from behind him. “Ya’d better come see him if ya know what’s good for ya.”

There.
Now
everything was going according to plan.

Act 1:

“A
reason?
” said the old wizard. He restrained the fury from his face. The boy before him had been the victim, and certainly did not need to be frightened any further. “There is
nothing
that can excuse -”

“What I did to him was worse.”

The old wizard stiffened in sudden horror. “Harry,
what have you done?
”

“I tricked Draco into believing that I’d tricked him into participating in a ritual that sacrificed his belief in blood purism. And that meant he couldn’t be a Death Eater when he grew up. He’d lost everything, Headmaster.”

There was a long quiet in the office, broken only by the tiny puffs and whistles of the fiddly things, which after enough time had come to seem like silence.

“Dear me,” said the old wizard, “I
do
feel silly. And
here
I was expecting you might try to redeem the heir of Malfoy by, say,
showing him true friendship and kindness
.”

“
Ha!
Yeah, like
that
would have worked.”

The old wizard sighed. This was taking it too far. “Tell me, Harry. Did it even
occur
to you that there was something
incongruous
about setting out to redeem someone through lies and trickery?”

“I did it without telling any direct lies, and since we’re talking about Draco Malfoy here, I think the word you’re looking for is
congruous
.” The boy looked rather smug.

The old wizard shook his head in despair. “And
this
is the hero. We’re all doomed.”

Act 5:

The long, narrow tunnel of rough stone, unlit except by a child’s wand, seemed to stretch on for miles.

The reason for this was simple: It
did
stretch on for miles.

The time was three in the morning, and Fred and George were starting the long way down the secret passage that led from a statue of a one-eyed witch in Hogwarts, to the cellar of the Honeydukes candyshop in Hogsmeade.

“How’s it doing?” said Fred in a low voice.

(Not that there’d be anyone listening, but there was something odd about talking in a normal voice when you were going through a secret passage.)

“Still on the fritz,” said George.

“Both, or -”

“Intermittent one fixed itself again. Other one’s same as ever.”

The Map was an extraordinarily powerful artifact, capable of tracking every sentient being on the school grounds, in real time, by name. Almost certainly, it had been created during the original raising of Hogwarts. It was
not good
that errors were starting to pop up. Chances were that no one except Dumbledore could fix it if it was broken.

And the Weasley twins weren’t about to turn the Map over to Dumbledore. It would have been an unforgivable insult to the Marauders - the four unknowns who’d managed to steal part of the
Hogwarts security system
, something probably forged by Salazar Slytherin himself, and twist it into
a tool for student pranking
.

Some might have considered it disrespectful.

Some might have considered it criminal.

The Weasley twins firmly believed that if Godric Gryffindor had been around to see it, he would have approved.

The brothers walked on and on and on, mostly in silence. The Weasley twins talked to each other when they were thinking through new pranks, or when one of them knew something the other didn’t. Otherwise there wasn’t much point. If they already knew the same information, they tended to think the same thoughts and make the same decisions.

(Back in the old days, whenever magical identical twins were born, it had been the custom to kill one of them after birth.)

In time, Fred and George clambered out into a dusty cellar, strewn with barrels and racks of strange ingredients.

Fred and George waited. It wouldn’t have been polite to do anything else.

Before too long a thin old man in black pajamas clambered down the steps that led into the cellar, yawning. “Hello, boys,” said Ambrosius Flume. “I wasn’t expecting you tonight. Out of stock already?”