Harry Potter and the Methods of Rationality

The forest scrolled by as the carriage rolled along, the trees moving past at a speed that seemed positively glacial by comparison to broomsticks or even cars. There was something oddly relaxing, Harry thought, about traveling that slowly. It had certainly relaxed the Defense Professor, who was slumped over with a small stream of drool coming out of his slack mouth and puddling on his robes.

Harry still hadn't decided what he was allowed to eat for lunch.

His library research hadn't turned up any sign of wizards speaking to nonmagical plants. Or any other nonmagical animals besides snakes, although Spell and Speak by Paul Breedlove had recounted the probably-mythical tale of a sorceress called the Lady of Flying Squirrels.

What Harry wanted to do was ask Professor Quirrell. The problem was that Professor Quirrell was too smart. Judging by what Draco had said, the Heir of Slytherin business was a major bombshell, and Harry wasn't sure he wanted anyone else to know. And the instant Harry asked about Parseltongue, Professor Quirrell would fix him with those pale blue eyes and say, 'I see, Mr. Potter, so you taught Mr. Malfoy the Patronus Charm and accidentally spoke to his snake.'

It wouldn't matter that it shouldn't be enough evidence to locate the true explanation as a hypothesis, let alone overcome its burden of prior improbability. Somehow the Defense Professor would deduce it anyway. There were times when Harry suspected that Professor Quirrell had way more background information than he was telling, his priors were simply too good. Sometimes he got his amazing deductions right even when his reasons were wrong. The problem was that Harry couldn't see how Professor Quirrell could've snuck in an extra clue about half the stuff he guessed. Just once Harry would have liked to make some sort of incredible deduction from something Professor Quirrell said which would catch him completely off guard.

"I shall have a bowl of green lentil soup, with soy sauce," Professor Quirrell said to the waitress. "And for Mr. Potter, a plate of Tenorman's family chili."

Harry hesitated in sudden dismay. He'd resolved to stick to vegetarian dishes for the moment, but he'd forgotten in his deliberations that Professor Quirrell did the actual ordering - and it would be awkward if he protested now -

The waitress bowed to them, and turned to go -

"Erm, excuse me, any meat in that from snakes or flying squirrels?"

The waitress didn't so much as blink an eye, only turned back to Harry, shook her head, bowed politely to him again, and resumed her walk toward the door.

(The other parts of Harry were snickering at him. Gryffindor was making sardonic comments about how a little social discomfort was enough to get him to resort to Cannibalism! (shouted by Hufflepuff), and Slytherin was remarking on how nice it was that Harry's ethics were flexible when it came to important goals like maintaining his relationship with Professor Quirrell.)

After the waitress had closed the door behind her, Professor Quirrell waved a hand to slide home the locking bar, spoke the usual four Charms to ensure privacy, and then said, "An interesting question, Mr. Potter. I wonder why you asked it?"

Harry kept his face steady. "I was looking up some facts about the Patronus Charm earlier," he said. "According to The Patronus Charm: Wizards Who Could and Couldn't, it turns out that Godric couldn't and Salazar could. I was surprised, so I looked up the reference, in Four Lives of Power. And then I discovered that Salazar Slytherin could supposedly talk to snakes." (Temporal sequence wasn't the same as causation, it wasn't Harry's fault if Professor Quirrell missed that.) "Further research turned up an old story about a mother goddess type who could talk to flying squirrels. I was a bit worried about the prospect of eating something that could talk."

And Harry took a casual sip of his water -

- just as Professor Quirrell said, "Mr. Potter, would I be correct in guessing that you are also a Parselmouth?"

When Harry was done coughing, he set his glass of water back down on the table, fixed his gaze on Professor Quirrell's chin rather than looking him in the eyes, and said, "So you are able to perform Legilimency through my Occlumency barriers, then."

Professor Quirrell was grinning widely. "I shall take that as a compliment, Mr. Potter, but no."

"I'm not buying this anymore," Harry said. "There's no way you came to that conclusion based on that evidence."

"Of course not," Professor Quirrell said equably. "I had planned to ask you that question today in any case, and simply chose an opportune moment. I have suspected since December, in fact -"

"December?" said Harry. "I found out yesterday!"

"Ah, so you did not realize the Sorting Hat's message to you was in Parseltongue?"

The Defense Professor had timed it exactly right the second time, too, just as Harry was taking a gulp of water to clear out his throat from the first coughing fit.

Harry hadn't realized, not until just now. Of course it was obvious the instant Professor Quirrell said it. Right, Professor McGonagall had even told him not to talk to snakes where anyone could see him, but he'd thought she'd meant not to be seen talking to any statues or architectural features in Hogwarts that looked like snakes. Double illusion of transparency, he'd thought he understood her, she'd thought he understood her - but how the hell -

"So," Harry said, "you performed Legilimency on me during my first Defense class, to find out what happened with the Sorting Hat -"

"Then I would not have found out in December." Professor Quirell leaned back, smiling. "This is not a puzzle you can solve on your own, Mr. Potter, so I will reveal the answer. Over the winter holiday, I was alerted to the fact that the Headmaster had filed a request for a closed judicial panel to review the case of one Mr. Rubeus Hagrid, whom you know as the Keeper of Keys and Grounds at Hogwarts, and who was accused of the murder of Abigail Myrtle in 1943."

"Oh, of course," said Harry, "that makes it downright obvious that I'm a Parselmouth. Professor, what the sweet slithering snakes -"