The problem with the Time-Turner approach is that (given what we understand of the Time-Turner's rules) he'd have to somehow fool first-iteration Harry (and Fred and George) in order to avoid a paradox. The Methods universe is full of tales of time-turning gone wrong; since saving lives is one obvious application of the Time-Turner, Dumbledore surely knows exactly what he can and cannot get away with in that respect.
You don't have to trick out time. You can have it work the way you want from the beginning. Harry didn't have to trick his past self into not knowing that he was being pranked in order to prank himself. That wouldn't even make sense.
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 88-89. The previous thread has passed 500 comments.
There is now a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)
The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system. Also: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18.
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: