Harry Potter and the Methods of Rationality

"

"I'm afraid I couldn't say."

"...That is not fair."

"I think it is extremely fair," said Professor Quirrell, and they entered through the bronze doors.

The time was just before noon, and Harry and Professor Quirrell were seated at the foot and head of a wide, long, flat table, in a sumptuously appointed private room with thoroughly cushioned couches and chairs along the walls, and soft curtains hanging everywhere.

They were about to eat lunch in Mary's Place, which Professor Quirrell had said was known to him as one of the best restaurants in Diagon Alley, especially for - his voice had dropped meaningfully - certain purposes.

It was the nicest restaurant that Harry had ever been in, and it was really eating away at Harry that Professor Quirrell was treating him to the meal.

The first part of the mission, to find an Occlumency instructor, had been a success. Professor Quirrell, smiling evilly, had told Griphook to recommend the best he knew, and not worry about the expense, since Dumbledore was paying it; and the goblin had smiled in return. There might have been a certain amount of smiling on Harry's part as well.

The second part of the plan had been a complete failure.

Harry was not allowed to take money out of his vault without Headmaster Dumbledore or some other school official present, and Professor Quirrell had not been given the vault key. Harry's Muggle parents could not authorize it because they were Muggles, and Muggles had around the same legal standing as children or kittens: they were cute, so if you tortured them in public you could get arrested, but they weren't people. Some reluctant provision had been made for recognizing the parents of Muggleborns as human in a limited sense, but Harry's adoptive parents did not fall into that legal category.

It seemed that Harry was effectively an orphan in the eyes of the wizarding world. As such, the Headmaster of Hogwarts, or his designees within the school system, were Harry's guardians until he graduated. Harry could breathe without Dumbledore's permission, but only so long as the Headmaster did not specifically prohibit it.

Harry had then asked if he could simply tell Griphook how to diversify his investments beyond stacks of gold coins sitting in his vault.

Griphook had stared blankly and asked what 'diversify' meant.

Banks, it seemed, did not make investments. Banks stored your gold coins in secure vaults for an annual fee.

The wizarding world did not have a concept of stock. Or equity. Or corporations. Businesses were run by families out of their personal vaults.

Loans were made by rich people, not banks. Though Gringotts would witness the contract, for a fee, and enforce its collection, for a much larger fee.

Good rich people let their friends borrow money and pay it back whenever. Bad rich people charged you interest.

There was no secondary market in loans.

Evil rich people charged you annual interest rates of at least 20%.

Harry had stood up, turned away, and rested his head against the wall.

Harry had asked if he needed the Headmaster's permission before he could start a bank.

Professor Quirrell had interrupted at this point, saying that it was time for lunch, and swiftly conducted a fuming Harry out of the bronze doors of Gringotts, through Diagon Alley, and to a fine restaurant called Mary's Place, where a room had been reserved for them. The owner had looked shocked at seeing Professor Quirrell accompanied by Harry Potter, but had conducted them to the room without complaint.

And Professor Quirrell had quite deliberately announced that he would pay the bill, seeming to rather enjoy the look on Harry's face.

"No," said Professor Quirrell to the waitress, "we will not require menus. I will have the daily special accompanied by a bottle of Chianti, and Mr. Potter will have the Diracawl soup to start, followed by a plate of Roopo balls, and treacle pudding for dessert."

The waitress, clad in robes that still looked severe and formal while being rather shorter than usual, bowed respectfully and departed, shutting the door behind her.

Professor Quirrell waved a hand in the direction of the door, and a bolt slid shut. "Note the bolt on the inside. This room, Mr. Potter, is known as Mary's Room. It happens to be proof against all scrying, and I do mean all; Dumbledore himself could detect nothing of what happens here. Mary's Room is used by two kinds of people. The first sort are engaged in illicit dalliances. And the second sort lead interesting lives."

"Really," said Harry.

Professor Quirrell nodded.

Harry's lips were parted in anticipation. "It would be a waste to just sit here and eat lunch, then, without doing anything special."

Professor Quirrell grinned, then took out his wand and flicked it in the direction of the door. "Of course," he said, "people who lead interesting lives take precautions more thorough than the dalliers. I have just sealed us in. Nothing will now pass in or out of this room - through the crack under the door, for example. And..."

Professor Quirrell then spoke no fewer than four different Charms, none of which Harry recognized.

"Even that does not really suffice," said Professor Quirrell. "If we were doing anything of truly great import, it would be necessary to perform another twenty-three checks besides those. If, say,