Maybe Harry needs to solve the nature of magic. Magic acts on human expectations: things happen the way they are expected to happen, within certain rules. Psychological features like intention, emotion, and desire have real effects on the outside world. It seems magic only makes sense in a "human-designed" universe. So the likeliest scenario to HP should be that his universe is a simulation. The limits of Time Turners could be viewed as rules imposed by the simulation-keepers to keep the simulation computable. The Mirror of Erised seems to suggest the same thing. It might be a sub-program baked into the fabric of the simulation to help inhabitants determine their CEV.
There would be an interesting kind of symmetry if Harry's current AI-box problem turns out to be a double-boxing. Will Harry talk himself out of Voldemort's box by warning that they all are in another box?
A problem with this that I see is that Harry's "End of the World" prophecy seems to imply the simulation has a Halting Oracle. I can think of some rationalizations for this, though.
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 113.
There is 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.)
IMPORTANT -- From the end of chapter 113: