I meant to add this when I originally wrote the above post, but forgot, probably because it's pretty obvious:
Quirrell was antsy to get back to his classes, of which there are not many left. And teaching the Killing Curse is a good way to make sure Harry is deeply in tune with his Dark Side when Quirrell executes his plot against Hermione. Harry's Dark Side will of course be exceptionally good at casting the Killing Curse, and casting it will make it easier for him to stay Dark when he wants to. Whenever Harry next gets back to his Light Side thereafter, he'll be alarmed at how right it felt for him to cast it; indeed, he'll probably start finding it hard to resist casting it whenever something activates his Dark Side.
I get the feeling that if Harry learns the Killing Curse he'll manage to tweak it somehow, on the order of Patronus 2.0 or partial Transfiguration.
I arrived at this idea by intuition - it seems to fit, but I don't think there's much explicit support. AFAICT I'm mostly pattern-matching on story logic, AK's plot significance and symmetry with Patronus, and Harry's talent for breaking things by thinking at them.
I think my probability estimate for this (given that Harry learns AK in the first place) is around 30%, but I suspect I'm poorly calibrated.
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: