The new thread, discussion 13, is here.
This is a new thread to discuss Eliezer Yudkowsky's Harry Potter and the Methods of Rationality and anything related to it. With three chapters recently the previous thread has very quickly reached 1000 comments. The latest chapter as of 25th March 2012 is Ch 80.
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: one, two, three, four, five, six, seven, eight, nine, ten, eleven.
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Eliezer Yudkowsky which is not supposed to be publicly available (which includes public statements by Eliezer that have been retracted).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.
Let's discuss Dementors. I was surprised to learn that a lot of people came away from TSPE believing in Harry's initial hypothesis, that Dementors had no minds of their own and were controlled by the expectations of the people nearest them. To me, this seemed conclusively disproved by something Harry isn't aware of: the fact that the dozen Dementors he scared away went back to their hundred-plus brethren in the central pit and thereafter all of them refused to tell the Aurors where Harry was, despite the fact that there were quite a lot of Aurors believing very strongly that they would.
If there's something I'm missing that rescues this hypothesis, I'd appreciate it being pointed out. At this point, I have to believe that whatever ritual (or possibly "law of magic", if we believe Harry) creates Dementors also imbues them with at least some independent decision-making ability, and that they have goals which include 'continuing to exist'.
Dementors as everyone but Harry sees them are more or less illusions created by a wizard's subconscious, but they are not limited to a person's expectations. They can react to stimulus, possibly in ways similar to organic life, but any displays of sapience are created in the minds of onlookers. As such there is no possible way that dementors could ever relay information to someone not already in possession of the knowledge.