Harry Potter and the Methods of Rationality

"Look, Daphne, I told you -" The Slytherin girl paused, as if trying to remember something, and then said, "I mean, I told you, what I See has to come to pass. If I try to change it, if anyone tries to change it, really terrible, awful, no good, extremely bad things will happen. And then it'll come to pass anyway. If I See you getting beaten up, I can't tell you that, because then you'd try to not go, and then -" Millicent stopped.

"And then?" Daphne said skeptically. "I mean, what happens if we just don't go?"

"I don't know!" said Millicent. "But it probably makes being eaten by Lethifolds look like a tea party!"

"Look, even I know that's not how prophecies work," Daphne said, then paused. "At least prophecies don't work like that in plays..." Admittedly, there were all sorts of tragedies where trying to avoid a prophecy made it happen, or where, on the other hand, trying to go along with a prophecy was the only reason why it happened. But you could make prophecies happen your own way if you were clever enough; or someone who loved you enough could take your place; or with enough effort it was possible to break a prophecy outright... Then again, in plays the Seers never remembered what they Saw, either...

Millicent must have seen Daphne's hesitation, because the other girl started looking a little more confident. "Well," Millicent said sharply, "this isn't a play! Look, I'll tell you if I See it being a hard battle or an easy one. But that's all I can do, you understand? And if I say 'hard' you can't not show up! Or - or -" Millicent's eyes rolled back in her head, and she intoned hollowly, "Those who try to cheat their destinies will come to sad and gloomy ends -"

Professor Sprout shook her head, her face looking tight.

"But -" said Susan. "But you helped Harry Potter that one time -"

"And it was made quite clear to me," Professor Sprout said in a voice that sounded like someone was using a Shrinking Charm to squeeze her throat, "that it was Professor Snape's job, and not mine, to keep order in Slytherin House - Miss Bones, please, you don't have to do this if -"

"Yes, I do have to," Susan said unhappily. "I'm a Hufflepuff, we have to be loyal."

"A mysterious parchment under your pillow?" said Harry Potter, looking up from where he was sitting, in the Quieted nook where they were studying. Then the boy's green eyes narrowed. "It wasn't from Santa Claus, was it?"

Pause.

"Okay," said Hermione. "I'm not going to ask, and you're not going to tell me, and we're both going to pretend you never said that and I don't know anything about it -"

Susan approached the table as soon as the older girl was alone, glancing around the Hufflepuff common room to make sure nobody was watching (the way Auntie had taught her to do it, so that it wouldn't be obvious that she was looking).

"Hey, Susie," said the seventh-year Hufflepuff. "Do you already need more -"

"Can I please talk to you privately for a bit?" Susan said.

Jaime Astorga, seventh-year of Slytherin, and until recently considered a promising upstart on the youth dueling circuit, stood ramrod straight in Professor Snape's office, with his teeth clenched tight and sweat trickling down his spine.

"I distinctly recall," said the Head of his House in a sardonic drawl, "that I warned you, and a number of others this very morning, that there were certain first-year girls who might prove annoying, if a fighter were incautious and allowed himself to be taken by surprise."

Professor Snape stalked in a slow circle around him.

"I -" said Jaime, as more sweat beaded on his forehead. He knew how ridiculous it sounded, how much of a pathetic excuse. "Sir, they shouldn't have been able to -" One first-year-girl shouldn't have been able to break his Protego, no matter what sort of ancient Charm she used - Greengrass must have had help -

But it was very clear that his Head of House wouldn't believe that.

"Oh, I quite agree," murmured Snape in a low tone, instinct with menace. "They shouldn't have. I begin to wonder if Mr. Malfoy, whatever his plotting, has a point, Astorga. It cannot be good for the repute of Slytherin's House if our fighters, rather than demonstrating their strength, lose to little girls!" Snape's voice had risen. "It is well that you had the good taste to be defeated by a little girl who is a fellow Slytherin of a Noble House, Astorga, or I would deduct points from you myself!"

Jaime Astorga's fists clenched at his side, but he couldn't think of a thing to say.

It was some time before Jaime Astorga was allowed to leave the presence of his Head of House.

And afterward, only the walls, the floor, and the ceiling saw Severus Snape's smile.