The boy waited, his face neutral.
"But suppose all the robes come from the store with a Charm already on them to keep them clean, which would be a useful sort of Charm for them to have. You found that out by spilling something on yourself earlier."
Now the boy's eyebrows lifted. "Is that your answer?"
"No, I haven't done Step 2, 'Do an experiment to test your hypothesis.'"
The boy closed his mouth again, and began to smile.
Hermione looked at the drinks can, which she'd automatically put into the cupholder at the window. She took it up and peered inside, and found that it was around one-third full.
"Well," said Hermione, "the experiment I want to do is to pour it on my robes and see what happens, and my prediction is that the stain will disappear. Only if it doesn't work, my robes will be stained, and I don't want that."
"Do it to mine," said the boy, "that way you don't have to worry about your robes getting stained."
"But -" Hermione said. There was something wrong with that thinking but she didn't know how to say it exactly.
"I have spare robes in my trunk," said the boy.
"But there's nowhere for you to change," Hermione objected. Then she thought better of it. "Though I suppose I could leave and close the door -"
"I have somewhere to change in my trunk, too."
Hermione looked at his trunk, which, she was beginning to suspect, was rather more special than her own.
"All right," Hermione said, "since you say so," and she rather gingerly poured a bit of green pop onto a corner of the boy's robes. Then she stared at it, trying to remember how long the original fluid had taken to disappear...
And the green stain vanished!
Hermione let out a sigh of relief, not least because this meant she wasn't dealing with all of the Dark Lord's magical power.
Well, Step 3 was measuring the results, but in this case that was just seeing that the stain had vanished. And she supposed she could probably skip Step 4, about the cardboard poster. "My answer is that the robes are Charmed to keep themselves clean."
"Not quite," said the boy.
Hermione felt a stab of disappointment. She really wished she wouldn't have felt that way, the boy wasn't a teacher, but it was still a test and she'd gotten a question wrong and that always felt like a little punch in the stomach.
(It said almost everything you needed to know about Hermione Granger that she had never let that stop her, or even let it interfere with her love of being tested.)
"The sad thing is," said the boy, "you probably did everything the book told you to do. You made a prediction that would distinguish between the robe being charmed and not charmed, and you tested it, and rejected the null hypothesis that the robe was not charmed. But unless you read the very, very best sort of books, they won't quite teach you how to do science properly. Well enough to really get the right answer, I mean, and not just churn out another publication like Dad always complains about. So let me try to explain - without giving away the answer - what you did wrong this time, and I'll give you another chance."
She was starting to resent the boy's oh-so-superior tone when he was just another eleven-year-old like her, but that was secondary to finding out what she'd done wrong. "All right."
The boy's expression grew more intense. "This is a game based on a famous experiment called the 2-4-6 task, and this is how it works. I have a rule - known to me, but not to you - which fits some triplets of three numbers, but not others. 2-4-6 is one example of a triplet which fits the rule. In fact... let me write down the rule, just so you know it's a fixed rule, and fold it up and give it to you. Please don't look, since I infer from earlier that you can read upside-down."
The boy said "paper" and "mechanical pencil" to his pouch, and she shut her eyes tightly while he wrote.
"There," said the boy, and he was holding a tightly folded piece of paper. "Put this in your pocket," and she did.
"Now the way this game works," said the boy, "is that you give me a triplet of three numbers, and I'll tell you 'Yes' if the three numbers are an instance of the rule, and 'No' if they're not. I am Nature, the rule is one of my laws, and you are investigating me. You already know that 2-4-6 gets a 'Yes'. When you've performed all the further experimental tests you want - asked me as many triplets as you feel necessary - you stop and guess the rule, and then you can unfold the sheet of paper and see how you did. Do you understand the game?"
"Of course I do," said Hermione.
"Go."
"4-6-8" said Hermione.
"Yes," said the boy.
"10-12-14", said Hermione.
"Yes," said the boy.
Hermione tried to cast her mind a little further afield, since it seemed like she'd already done all the testing she needed, and yet it couldn't be that easy, could it?
"1-3-5."
"Yes."
"Minus 3, minus 1, plus 1."
"Yes."
Hermione couldn't think of anything else to do. "The rule is that the numbers have to increase by two each time."
"Now suppose I tell you," said the boy, "that this test is harder than it looks, and that only 20% of grownups get it right."
Hermione frowned. What had she missed? Then, suddenly, she thought of a test she still needed to do.
"2-5-8!" she said triumphantly.
"Yes."
"10-20-30!"
"Yes."
"The real answer is that the numbers have to go up by the same amount each time. It doesn't have to be 2."
"Very well," said the boy, "take the paper out and see how you did."
Hermione took the paper out of her pocket and unfolded it.
Three real numbers in increasing order, lowest to highest.
Hermione's jaw dropped. She had the distinct feeling of something terribly unfair having been done to her, that the boy was a dirty rotten cheating liar, but when she cast her mind back she couldn't think of any wrong responses that he'd given.
"What you've just discovered is called 'positive bias'," said the boy. "You had a rule in your mind, and you kept on thinking of triplets that should make the rule say 'Yes'. But you didn't try to test any triplets that should make the rule say 'No'. In fact you didn't get a single 'No', so 'any three numbers' could have just as easily been the rule. It's sort of like how people imagine experiments that could confirm their hypotheses instead of trying to imagine experiments that could falsify them - that's not quite exactly the same mistake but it's close. You have to learn to look on the negative side of things, stare into the darkness. When this experiment is performed, only 20% of grownups get the answer right. And many of the others invent fantastically complicated hypotheses and put great confidence in their wrong answers since they've done so many experiments and everything came out like they expected."
"Now," said the boy, "do you want to take another shot at the original problem?"
His eyes were quite intent now, as though this were the real test.
Hermione shut her eyes and tried to concentrate. She was sweating underneath her robes. She had an odd feeling that this was the hardest she'd ever been asked to think on a test or maybe even the first time she'd ever been asked to think on a test.
What other experiment could she do? She had a Chocolate Frog, could she try to rub some of that on the robes and see if it vanished? But that still didn't seem like the kind of twisty negative thinking the boy was asking for. Like she was still asking for a 'Yes' if the Chocolate Frog stain disappeared, rather than asking for a 'No'.
So... on her hypothesis... when should the pop... not vanish?
"I have an experiment to do," Hermione said. "I want to pour some pop on the floor, and see if it doesn't vanish. Do you have some paper towels in your pouch, so I can mop up the spill if this doesn't work?"
"I have napkins," said the boy. His face still looked neutral.
Hermione took the can, and poured a small bit of pop onto the floor.
A few seconds later, it va
nished.
Then the realisation hit her and she felt like kicking herself. "Of course! You gave me that can! It's not the robe that's enchanted, it was the pop all along!"
The boy stood up and bowed to her solemnly. He was grinning widely now. "Then... may I help you with your research, Hermione Granger?"
"I, ah..." Hermione was still feeling the rush of euphoria, but she wasn't quite sure about how to answer that.
They were interrupted by a weak, tentative, faint, rather reluctant knocking at the door.
The boy turned and looked out the window, and said, "I'm not wearing my scarf, so can you get that?"
It was at this point that Hermione realised why the boy - no, the Boy-Who-Lived, Harry Potter - had been wearing the scarf over his head in the first place, and felt a little silly for not realising it earlier. It was actually sort of odd, since she would have thought Harry Potter would proudly display himself to the world; and the thought occurred to her that he might actually be shyer than he seemed.
When Hermione pulled the door open, she was greeted by a trembling young boy who looked exactly like he knocked.
"Excuse me," said the boy in a tiny voice, "I'm Neville Longbottom. I'm looking for my pet toad, I, I can't seem to find it anywhere on this carriage... have you seen my toad?"
"No," Hermione said, and then her helpfulness kicked in full throttle. "Have you checked all the other compartments?"
"Yes," whispered the boy.
"Then we'll just have to check all the other carriages," Hermione said briskly. "I'll help you. My name is Hermione Granger, by the way."
The boy looked like he might faint with gratitude.
"Hold on," came the voice of the other boy - Harry Potter. "I'm not sure that's the best way to do it."
At this Neville looked like he might cry, and Hermione swung around, angered. If Harry Potter was the sort of person who'd abandon a little boy just because he didn't want to be interrupted... "What? Why not?"
"Well," said Harry Potter, "It's going to take a while to check the whole train by hand, and we might miss the toad anyway, and if we didn't find it by the time we're at Hogwarts, he'd be in trouble. So what would make a lot more sense is if he went directly to the front carriage, where the prefects are, and asked a prefect for help. That was the first thing I did when I was looking for you, Hermione, although they didn't actually know. But they might have spells or magic items that would make it a lot easier to find a toad. We're only first-years."
That... did make a lot of sense.
"Do you think you can make it to the prefects' carriage on your own?" asked Harry Potter. "I've sort of got reasons for not wanting to show my face too much."
Suddenly Neville gasped and took a step back. "I remember that voice! You're one of the Lords of Chaos! You're the one who gave me chocolate!"
What? What what what?
Harry Potter turned his head from the window and rose dramatically. "I never!" he said, voice full of indignation. "Do I look like the sort of villain who would give sweets to a child?"
Neville's eyes widened. "You're Harry Potter? The Harry Potter? You?"
"No, just a Harry Potter, there are three of me on this train -"
Neville gave a small shriek and ran away. There was a brief pattering of frantic footsteps and then the sound of a carriage door opening and closing.
Hermione sat down hard on her bench. Harry Potter closed the door and then sat down next to her.
"Can you please explain to me what's going on?" Hermione said in a weak voice. She wondered if hanging around Harry Potter meant always being this confused.
"Oh, well, what happened was that Fred and George and I saw this poor small boy at the train station - the woman next to him had gone away for a bit, and he was looking really frightened, like he was sure he was about to be attacked by Death Eaters or something. Now, there's a saying that the fear is often worse than the thing itself, so it occurred to me that this was a lad who could actually benefit from seeing his worst nightmare come true and that it wasn't so bad as he feared -"
Hermione sat there with her mouth wide open.
"- and Fred and George came up with this spell to make the scarves over our faces darken and blur, like we were undead kings and those were our grave shrouds -"
She didn't like at all where this was going.
"- and after we were done giving him all the sweets I'd bought, we were like, 'Let's give him some money! Ha ha ha! Have some Knuts, boy! Have a silver Sickle!' and dancing around him and laughing evilly and so on. I think there were some people in the crowd who wanted to interfere at first, but bystander apathy held them off at least until they saw what we were doing, and then I think they were all too confused to do anything. Finally he said in this tiny little whisper 'go away' so the three of us all screamed and ran off, shrieking something about the light burning us. Hopefully he won't be as scared of being bullied in the future. That's called desensitisation therapy, by the way."
Okay, she hadn't guessed right about where this was going.
The burning fire of indignation that was one of Hermione's primary engines sputtered into life, even though part of her did sort of see what they'd been trying to do. "That's awful! You're awful! That poor boy! What you did was mean!"
"I think the word you're looking for is enjoyable, and in any case you're asking the wrong question. The question is, did it do more good than harm, or more harm than good? If you have any arguments to contribute to that question I'm glad to hear them, but I won't entertain any other criticisms until that one is settled. I certainly agree that what I did looks all terrible and bullying and mean, since it involves a scared little boy and so on, but that's hardly the key issue now is it? That's called consequentialism, by the way, it means that whether an act is right or wrong isn't determined by whether it looks bad, or mean, or anything like that, the only question is how it will turn out in the end - what are the consequences."
Hermione opened her mouth to say something utterly searing but unfortunately she seemed to have neglected the part where she thought of something to say before opening her mouth. All she could come up with was, "What if he has nightmares?"
"Honestly, I don't think he needed our help to have nightmares, and if he has nightmares about this instead, then it'll be nightmares involving horrible monsters who give you chocolate and that was sort of the whole point."
Hermione's brain kept hiccoughing in confusion every time she tried to get properly angry. "Is your life always this peculiar?" she said at last.
Harry Potter's face gleamed with pride. "I make it that peculiar. You're looking at the product of a lot of hard work and elbow grease."
"So..." Hermione said, and trailed off awkwardly.
"So," Harry Potter said, "how much science do you know exactly? I can do calculus and I know some Bayesian probability theory and decision theory and a lot of cognitive science, and I've read The Feynman Lectures (or volume 1 anyway) and Judgment Under Uncertainty: Heuristics and Biases and Language in Thought and Action and Influence: Science and Practice and Rational Choice in an Uncertain World and Godel, Escher, Bach and A Step Farther Out and -"
The ensuing quiz and counter-quiz went on for several minutes before being interrupted by another timid knock at the door. "Come in," she and Harry Potter said at almost the same time, and it slid back to reveal Neville Longbottom.
Neville was actually crying now. "I went to the front carriage and found a p-prefect but he t-told me that prefects weren't to be bothered over little things like m-missing toads."
The Boy-Who-Lived's face changed. His lips set in a thin line. His voice, when he spoke, was cold and grim. "What were his colours? Green and silver?"
"N-no, his badge was r-red and gold."
"Red and gold!" burst out Hermione. "But those are Gryffindor's colours!"
Harry Potter hissed at that, a frightening sort of sound that could have come from a live snake and made both her and Neville flinch. "I suppose," Harry Potter s
pat, "that finding some first-year's toad isn't heroic enough to be worthy of a Gryffindor prefect. Come on, Neville, I'll come with you this time, we'll see if the Boy-Who-Lived gets more attention. First we'll find a prefect who ought to know a spell, and if that doesn't work, we'll find a prefect who isn't afraid of getting their hands dirty, and if that doesn't work, I'll start recruiting my fans and if we have to we'll take apart the whole train screw by screw."
The Boy-Who-Lived stood up and grabbed Neville's hand in his, and Hermione realised with a sudden brain hiccough that they were nearly the same size, even though some part of her had insisted that Harry Potter was a foot taller than that, and Neville at least six inches shorter.
"Stay!" Harry Potter snapped at her - no, wait, at his trunk - and he closed the door behind him firmly as he left.
She probably should have gone with them, but in just a brief moment Harry Potter had turned so scary that she was actually rather glad she hadn't thought to suggest it.
Hermione's mind was now so jumbled that she didn't even think she could properly read "History: A Hogwarts". She felt as if she'd just been run over by a steamroller and turned into a pancake. She wasn't sure what she was thinking or what she was feeling or why. She just sat by the window and stared at the moving scenery.
Well, she did at least know why she was feeling a little sad inside.
Maybe Gryffindor wasn't as wonderful as she had thought.
Chapter 9: Title Redacted, Part I
All your base are belong to J. K. Rowling.
1,000 REVIEWS IN 26 DAYS WOOHOO AWESOME POWA! 30 DAYS 1,189 REVIEWS COMBO IS CONTINUING! YEAH! YOU PEOPLE ARE THE BEST! THIS IS SPARTAAAAA!
Ahem.
The third-generation quarks were also called "truth" and "beauty" before "top" and "bottom" won out; my birthdate is around Hermione's, and when I was eleven, I used "truth" and "beauty".
When Part I of this chapter was first posted, I said that if anyone guessed what the last sentence was talking about before the next update, I would tell them the entire rest of the plot.
Harry Potter and the Methods of Rationality Page 12