Harry Potter and the Methods of Rationality

To-do 2. Actually this is To-do 1 and the other is To-do 2. Go through the bookshelves of the Hogwarts and Ravenclaw libraries, familiarising yourself with the system and making sure you've at least read all the book titles. Second pass: read all tables of contents. Coordinate with Hermione who has a much better memory than you. Find out if there's an interlibrary loan system at Hogwarts and see if the two of you, especially Hermione, can visit those libraries too. If other Houses have private libraries, figure out how to access legally or sneak in.

Option 3a: Swear Hermione to secrecy and try to start researching 'From Slytherin to Slytherin: if you would seek my secrets, speak to my snake.' Problem: This sounds highly confidential and it could take quite a while to randomly run across a book containing a hint.

To-do 0: Check out what sort of information-search-and-retrieval spells exist, if any. Library magic isn't as ultimately important as mind magic but it has a much higher priority.

Option 3b: Look for a spell to magically bind Draco Malfoy to secrecy, or magically verify the sincerity of Draco's promise to keep a secret (Veritaserum?), and then ask him about Slytherin's message...

Actually... Harry had a pretty bad feeling about option 3b.

Now that Harry thought about it, he didn't feel all that great about option 3a, either.

Harry's thoughts flashed back to possibly the worst moment of his life to date, those long seconds of blood-freezing horror beneath the Hat, when he thought he'd already failed. He'd wished then to fall back just a few minutes in time and change something, anything before it was too late...

And then it had turned out to not be too late after all.

Wish granted.

You couldn't change history. But you could get it right to start with. Do something differently the first time around.

This whole business with seeking Slytherin's secrets... seemed an awful lot like the sort of thing where, years later, you would look back and say, 'And that was where it all started going wrong.'

And he would wish desperately for the ability to fall back through time and make a different choice...

Wish granted. Now what?

Harry slowly smiled.

It was a rather counterintuitive thought... but...

But he could, there was no rule saying he couldn't, he could just pretend he'd never heard that little whisper. Let the universe go on in exactly the same way it would have if that one critical moment had never occurred. Twenty years later, that was what he would desperately wish had happened twenty years ago, and twenty years before twenty years later happened to be right now. Altering the distant past was easy, you just had to think of it at the right time.

Or... this was even more counterintuitive... he could even inform, oh, say, Professor McGonagall, instead of Draco or Hermione. And she could get a few good people together and get that little extra spell taken off the Hat.

Why, yes. That sounded like a remarkably good idea once Harry had actually thought of it.

So very obvious in retrospect, and yet somehow, Option 3c and Option 3d just hadn't occurred to him.

Harry awarded himself +1 point on his anti-Dark-Lord-Harry program.

It had been an awfully cruel prank the Hat had played on him, but you couldn't argue with the results on consequentialist grounds. It certainly did give him a better idea of the victim's perspective, though.

To-do 4: Apologise to Neville Longbottom.

Okay, he was on a roll here, now he just had to keep it up. In every day, in every way, I'm getting Lighter and Lighter...