EDIT: New discussion thread here.
This is a new thread to discuss Eliezer Yudkowsky's Harry Potter and the Methods of Rationality and anything related to it. With two chapters recently the previous thread has very quickly reached 500 comments. The latest chapter as of 17th March 2012 is Ch. 79.
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.
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Eliezer Yudkowsky which is not supposed to be publicly available (which includes public statements by Eliezer that have been retracted).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.
Dumbledore is a sonovabitch. Harry's wrong about how Snape heard the prophesy. Malfoy and Friends may be wrong about how Narcissa died. The whole matter of lighting a live chicken on fire may be a strange misunderstanding. But Dumbledore is still a right bastard for what he did to Snape, which we may put together from chapters 17, 18, 27, & the renumbered 76.
Chapters 17 & 76 tell us how Snape pursued Lily while he was her friend. (Or that's what Snape thinks of what he was doing. He was probably a 'Nice Guy' about it and it would probably have failed in the usual fashion. But that wasn't allowed to happen.)
To be clear: despite the (deservedly) doomed-to-the-friendzone fate of Snape's attempts to woo Lily, Dumbeldore nonetheless stepped in and instigated fights between Snape and Lily by writing things in Lily's potions book. While headmaster and responsible for the well being of children, Dumbledore sabotaged a relationship between children! He might even have done this because it did not fit the story he foresaw for a very Slytherin Snape to remain friends with a pretty and heroic Lily. He might have done it for even worse reasons.
Yes, worse. Dumbledore said, "Hogwarts needs an evil Potions Master to be a proper magical school, " in chapter 18. If he is willing to allow the abuse of children to keep an evil potions master, we might believe he would abuse a sixteen- or seventeen-year-old to make an evil potions master.
Chapters 27 & 76 tell us how it looked to Snape when it ended, and most importantly that he did not understand what happened and, until the events of this fic, knew he did not understand and was seeking understanding. How desperate for understanding must he have been, to ask an eleven-year-old? To Snape, the final rejection was not justified by what he knew of Lily, and so it seemed to come out of nowhere.
Snape wouldn't, couldn't know why the new fights with Lily were starting. For the fights to continue, Lily must have remained unaware that Snape was not writing in her potions book. And for Lily to remain unaware, Snape could not find out the reason for the fights. From Snape's perspective, his only real friendship suddenly encountered incomprehensible, insurmountable obstacles in his fifth year. And then it fell apart and it was all his fault.
The reason Snape does not understand why Lily didn't forgive him is that he is missing information. He does not know about the things Dumbledore wrote in her potions book while allowing Lily to believe it was Snape. When things regularly happen to a person without that person knowing why, especially when those things involve loss of something valued, it can make the person habitually insecure. Snape was probably already insecure on account of his home life and status as a target for bullies. Insecure people often become hostile and abusive to defend themselves. That is to say, Dumbledore made Snape a villain, possibly on purpose, possibly because he felt it made a more fitting story than would a life of Snape's own choosing.
It is my hope that Snape will read Lily's fifth year potions book, will understand that Dumbledore ruined his like, will dedicate himself to killing Dumbledore, and will be successful before the close of the fic.
I have to agree with fezziwig that I notice that I'm confused about this idea that D writing in Lily's book somehow destroyed any hope of friendship between them. I don't understand your scenario: you think Lily was upset about the writing, blamed Snape, but never mentioned it, and that was enough to destroy a friendship? And Dumbledore somehow knew that writing in a book would cause this effect? "I want to destroy Snape's friendship... I know, I'll write in his friend's book!"
Given all the weird things that happen at Hogwarts, souls trapped in books and strange notes found under pillows and time travel, I kinda doubt Lily would stick to the hypothesis that it must be Snape, and never mention it.