Harry Potter and the Methods of Rationality discussion thread, part 23, chapter 94

elharo

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 94. The previous thread has passed 200 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, 19, 20, 21, 22.

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Yudkowsky which is not supposed to be publicly available (which includes public statements by Eliezer that have been retracted).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Yudkowsky which is not supposed to be publicly available (which includes public statements by Eliezer that have been retracted).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

Off the top of my head, something that simple doesn’t seem to match with the apparent safety of time-turners. Something that just reconfigures things “freely” will reconfigure stuff dangerously on occasion. Even if the time-turner will hide the reconfiguration, people will probably notice something like “there’s bad luck around time-turners”.

Note that things that appear “simple” to humans are not so at small scales. It’s much simpler for someone that time-turns to become insane or even just die rather than remain the same person except not speaking of some things.

Also, “information” is tricky. At some point in one of the new chapters, Minerva notices that Harry seems different only a few minutes after having entered a closed room. Let’s assume for now it’s because he’s from the future. (E.g., the one that entered is still in the room, under the cloak, and will return after six hours to exit the room.) If she doesn’t realize it, can she still time-turn? What if she finds out something that confirms it after five minutes, is she blocked then? Is she blocked if she deduces with high certainty something about the future from the fact that Harry returned. (At the minimum, if she realizes that Harry came back, she learned that he will not die in the next six hours.) What if she turns back six hours, and in the past she learns a piece of information that allows her to deduce with whatever level of certainty both that Harry went to the future, and something about what he did there?

(Example: at 1PM Harry builds a one-time pad and hides it. 12 hours later, he writes something about his present and XORs it with the one-time pad. He turns back six hours, and tells the encrypted text to Hermione, who memorizes it. Can she turn? She doesn’t really know anything more about the future than if he would have told her “I have information from six hours in the future”. But if she now turns back another six hours and finds the one-time pad, she’ll be able to obtain the information from 12 hours in her subjective future.)

Well— we're deep in the meta philosophy of a fictional world, so I'm not sure that any great insight will come from the discussion.

I'm unsure of how to resolve the apparent safety of time tuners with the idea that there is an optimization process selecting a permissible outcome unless I wave my arms and say that the optimization process is moral, perhaps borrowing the objectives of the operator (like the sorting hat). One way to do this is to note that bad things happening increase the probability of more time tuner usage, which a human-interest blind metr... (read more)