If the laws of reality are simulated, then they must be computable. A giant switch statement isn't going to let you figure out how to make time travel consistent. They couldn't easily check every possibility and see if it's consistent. Even if they did, that would mean they're simulating all of them, including the inconsistent ones, and there'd be no reason for Harry to find himself in a consistent one.
The anthropic principle solves Harry finding himself in a consistent one nicely. We don't know about the paradoxical universes because time/magic destroys them. You could also propose that when paradox occurs time goes back to the point of paradox and makes changes, inserts prophecies, etc. (maybe even uses mind magic?) to attempt to correct, destroying only the portion of the time-stream that came after. In this version there is actually just one time stream, not many, and it loads from the last checkpoint so to speak whenever a paradox results.
Results...
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 109.
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.)
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: