Harry Potter and the Methods of Rationality discussion thread, part 19, chapter 88-89

Vaniver

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:

You do not need to rot13 anything about HP:MoR or the original Harry Potter series unless you are posting insider information from Eliezer Yudkowsky which is not supposed to be publicly available (which includes public statements by Eliezer that have been retracted).

If there is evidence for X in MOR and/or canon then it’s fine to post about X without rot13, even if you also have heard privately from Eliezer that X is true. But you should not post that “Eliezer said X is true” unless you use rot13.

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:

You do not need to rot13 anything about HP:MoR or the original Harry Potter series unless you are posting insider information from Eliezer Yudkowsky which is not supposed to be publicly available (which includes public statements by Eliezer that have been retracted).

If there is evidence for X in MOR and/or canon then it’s fine to post about X without rot13, even if you also have heard privately from Eliezer that X is true. But you should not post that “Eliezer said X is true” unless you use rot13.

It's not clear what happens when there are multiple possible stable time loops. For example, why he ended up with a paper that says "DON'T MESS WITH TIME TRAVEL" instead of the semiprime factored, even though either would work. However, it can't do anything that results in a paradox. If Harry's going to go back and try to save Hermione whether or not he sees his future self save her, there is conceivable some loophole in which she is not saved, but it seems much more likely she'd just get saved.

This isn't like trying to factor a semiprime. This is like trying to write a specific phrase and send it back. You can mess it up, and if you don't get anything back you know you did, but it doesn't seem very plausible.

why he ended up with a paper that says "DON'T MESS WITH TIME TRAVEL" instead of the semiprime factored, even though either would work

Because if he'd gotten back a number, he would have kept pushing until he did something that broke time, thereby causing a paradox. The only way to head off paradox was to cut his line of inquiry off then and there.