Eliezer Yudkowsky - Harry Potter and the Methods of Rationality

"Stop," said Professor McGonagall.

Harry stopped. He had just been about to point out that at least they knew the Dark Lord wouldn't attack, since he was dead.

"I think I might not have made myself clear," the witch said, her precise Scottish voice sounding even more careful. "Did anything happen to you personally that frightened you, Mr. Potter?"

"What happened to me personally is only anecdotal evidence," Harry explained. "It doesn't carry the same weight as a replicated, peer-reviewed journal article about a controlled study with random assignment, many subjects, large effect sizes and strong statistical significance."

Professor McGonagall pinched the bridge of her nose, inhaled, and exhaled. "I would still like to hear about it," she said.

"Um..." Harry said. He took a deep breath. "There'd been some muggings in our neighborhood, and my mother asked me to return a pan she'd borrowed to a neighbor two streets away, and I said I didn't want to because I might get mugged, and she said, 'Harry, don't say things like that!' Like thinking about it would make it happen, so if I didn't talk about it, I would be safe. I tried to explain why I wasn't reassured, and she made me carry over the pan anyway. I was too young to know how statistically unlikely it was for a mugger to target me, but I was old enough to know that not-thinking about something doesn't stop it from happening, so I was really scared."

"Nothing else?" Professor McGonagall said after a pause, when it became clear that Harry was done. "There isn't anything else that happened to you?"

"I know it doesn't sound like much," Harry defended. "But it was just one of those critical life moments, you see? I mean, I knew that not thinking about something doesn't stop it from happening, I knew that, but I could see that Mum really thought that way." Harry stopped, struggling with the anger that was starting to rise up again when he thought about it. "She wouldn't listen . I tried to tell her, I begged her not to send me out, and she laughed it off . Everything I said, she treated like some sort of big joke..." Harry forced the black rage back down again. "That's when I realised that everyone who was supposed to protect me was actually crazy, and that they wouldn't listen to me no matter how much I begged them, and that I couldn't ever rely on them to get anything right." Sometimes good intentions weren't enough, sometimes you had to be sane...

There was a long silence.

Harry took the time to breathe deeply and calm himself down. There was no point in getting angry. There was no point in getting angry. All parents were like that, no adult would lower themselves far enough to place themselves on level ground with a child and listen, his genetic parents would have been no different. Sanity was a tiny spark in the night, an infinitesimally rare exception to the rule of madness, so there was no point in getting angry.

Harry didn't like himself when he was angry.

"Thank you for sharing that, Mr. Potter," said Professor McGonagall after a while. There was an abstracted look on her face (almost exactly the same look that had appeared on Harry's own face while experimenting on the pouch, if Harry had only seen himself in a mirror to realise that). "I shall have to think about this." She turned towards the alley mouthway, and raised her wand -

"Um," Harry said, "can we go get the healer's kit now?"

The witch paused, and looked back at him steadily. "And if I say no - that it is too expensive and you won't need it - then what?"

Harry's face twisted in bitterness. "Exactly what you're thinking, Professor McGonagall. Exactly what you're thinking. I conclude you're another crazy adult I can't talk to, and I start planning how to get my hands on a healer's kit anyway."

"I am your guardian on this trip," Professor McGonagall said with a tinge of danger. "I will not allow you to push me around."

"I understand," Harry said. He kept the resentment out of his voice, and didn't say any of the other things that came to mind. Professor McGonagall had told him to think before he spoke. He probably wouldn't remember that tomorrow, but he could at least remember it for five minutes.

The witch's wand made a slight circle in her hand, and the noises of Diagon Alley came back. "All right, young man," she said. "Let's go get that healer's kit."

Harry's jaw dropped in surprise. Then he hurried after her, almost stumbling in his sudden rush.

The shop was the same as they had left it, recognisable and unrecognisable items still laid out on the slanted wooden display, the grey glow still protecting and the salesgirl back in her old position. The salesgirl looked up as they approached, her face showing surprise.

"I'm sorry," she said as they got closer, and Harry spoke at almost the same moment, "I apologise for -"

They broke off and looked at each other, and then the salesgirl laughed a little. "I didn't mean to get you in trouble with Professor McGonagall," she said. Her voice lowered conspiratorially. "I hope she wasn't too awful to you."

" Della! " said Professor McGonagall, sounding scandalised.

"Bag of gold," Harry said to his pouch, and then looked back up at the salesgirl while he counted out five Galleons. "Don't worry, I understand that she's only awful to me because she loves me."

He counted out five Galleons to the salesgirl while Professor McGonagall was spluttering something unimportant. "One Emergency Healing Pack Plus, please."

It was actually sort of unnerving to see how the Widening Lip swallowed the briefcase-sized medical kit. Harry couldn't help wondering what would happen if he tried climbing into the mokeskin pouch himself, given that only the person who put something in was supposed to be able to take it out again.

When the pouch was done... eating... his hard-won purchase, Harry swore he heard a small burping sound afterward. That had to have been spelled in on purpose. The alternative hypothesis was too horrifying to contemplate... in fact Harry couldn't even think of any alternative hypotheses. Harry looked back up at the Professor, as they began walking through Diagon Alley once more. "Where to next?"

Professor McGonagall pointed toward a shop that looked as if it had been made from flesh instead of bricks and covered in fur instead of paint. "Small pets are permitted at Hogwarts - you could get an owl to send letters, for example -"

"Can I pay a Knut or something and rent an owl when I need to send mail?"

"Yes," said Professor McGonagall.

"Then I think emphatically no. "

Professor McGonagall nodded, as though ticking off a point. "Might I ask why not?"

"I had a pet rock once. It died."

"You don't think you could take care of a pet?"

"I could, " Harry said, "but I would end up obsessing all day long about whether I'd remembered to feed it that day or if it was slowly starving in its cage, wondering where its master was and why there wasn't any food."

"That poor owl," the older witch said in a soft voice. "Abandoned like that. I wonder what it would do."

"Well, I expect it'd get really hungry and start trying to claw its way out of the cage or the box or whatever, though it probably wouldn't have much luck with that -" Harry stopped short.

The witch went on, still in that soft voice. "And what would happen to it afterward?"

"Excuse me," Harry said, and he reached up to take Professor McGonagall by the hand, gently but firmly, and steered her into yet another alleyway; after ducking so many well-wishers the process had become almost unnoticeably routine. "Please cast that silencing spell."

" Quietus. "