Harry Potter and the Methods of Rationality discussion thread, part 16, chapter 85

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The next discussion thread is here.

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 85. The previous thread has long passed 500 comments. Comment in the 15th thread until you read chapter 85.

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.

As a reminder, it’s often useful to start your comment by indicating which chapter you are commenting on.

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Eliezer Yudkowsky which is not supposed to be publicly available (which includes public statements by Eliezer that have been retracted).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.

The next discussion thread is here.

As a reminder, it’s often useful to start your comment by indicating which chapter you are commenting on.

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Eliezer Yudkowsky which is not supposed to be publicly available (which includes public statements by Eliezer that have been retracted).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.

In canon, Dumbledore claims that Voldemort's soul latched onto Harry's soul, which means that this would work. Dumbledore is very smart and knows much more about magic than I do, so I think that it would probably work.

Souls might not exist in HPMOR. But I think they very well might. Otherwise:

Dumbledore is wrong. That doesn't seem likely on the basis of his general intelligence alone. Since he's really experienced and has access to tons of knowledge Dumbledore is even more likely to be right because he has evidence for souls that we don't.
Magic becomes bizarre. Souls are really the only way to make sense of Human to Animal transfiguration, or the fact that Horcruxes require murder specifically to divide one's identity, and they're referenced a lot elsewhere in the magic system (for example, with the Dementor's Kiss).
Voldemort wouldn't have survived. But he did.

Since there's no HPMOR world evidence against souls, and some evidence for souls, rational people inside HPMOR should believe in souls. This is sort of similar to how rational people from thousands of years ago probably would have been justified in believing in a deistic God.

We, however, have access to a counterargument, because we live outside HPMOR. The best reason to disbelieve in HPMOR souls is that Eliezer probably wouldn't like them. That would overwhelm the above three problems, if Eliezer dislikes souls enough to either put a lot of extra work into the story in order to solve those problems, or enough to feel justified in leaving the problems as is.

I can't evaluate that, because I don't know Eliezer's preferences.

In canon, Dumbledore claims that Voldemort's soul latched onto Harry's soul, which means that this would work. Dumbledore is very smart and knows much more about magic than I do, so I think that it would probably work.

Latching onto Harry's soul doesn't prove that mutual horcruxes would work since it doesn't address my example of destroying horcruxes one at a time, and I'm pretty sure Dumbledore nowhere says that the mutual horcrux scheme would work.