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 121.

Plans for next chapter release:

The last chapter will post on March 14th, 2015, at 9AM Pacific (4PM UTC).
Thank you all for reading.

There is a site dedicated to the story at, 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

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Yudkowsky which is not supposed to be publicly available (which includes public statements by Eliezer that have been retracted).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

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39 comments, sorted by Click to highlight new comments since: Today at 5:23 AM

I am among those with a sympathetic view of Snape. This was a satisfying chapter for me.

He may post the last chapter at 9:00, but I'm not reading it until 9:26 and 53.58979… seconds. It wouldn't be right.

I always thought pi hour was 3 in the afternoon. (3.14 15:9:26), or plausibly 2 in the afternoon (3.14 1:59:26) if you go with hours mod 12 and then choose the one where you're awake.

not in 2015 it isnt.

Ah, I see :)

Although honestly, what kind of idiot had the idea to order the date mm/dd/yyyy?

It was the only way to make peace between the little and big endians.

It's from the most common spoken order. "March fourteenth, twenty-fifteen."

Are you sure that's right chronologically? Just because in the UK we use dd/mm/yy and we say "Fourteenth of March, twenty-fifteen".

Japan apparently uses yy/mm/dd which makes even more sense, but I have no idea how they pronounce their dates. Point being, I'm not sure which order things actually evolved in.

Nope, no idea, since our records of the spoken language of the past are bad and I'm lazy. Maybe written and spoken dates slowly co-evolved, since it does appear that the m/d/y trend only dates back to the 17th century or so.


In the US, not everywhere.

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This order (including the m/dd/yy abbreviation) was wisely chosen so that Super Pi Day would actually happen once a century. Without that reason, it's completely illogical, so there is no other possible explanation.

That order is based on the increasing size of the sets of possible values, of course.


It was a compromise to end the war between the big endians and little endians.

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"Drop dead, Potter."

OK, that one got me to chuckle out loud.

Hm. So far, while I've been enjoying these epilogue chapters, it feels like there's not ENOUGH of them. I'm not sure the story can be given a satisfying conclusion with just one more chapter.

...Of course, in theory the chapter can be 100,000 words long, but...

Yeah, only one more chapter, and Harry hasn't even spoken to Hermione yet. Or his parents. Or gone back to the mirror to see if they could get Dumbledore out. No Bellatrix either. Or Dementors.

No Merlin or Atlantis either, though I suppose neither of those is gonna happen.

Or either of them speaking to Hermione's parents.

I also wonder if Lesath was allowed to remember his involvement in V-day.

I think Eliezer has given information about his word counts that suggests that the last chapter will be on the order of 10k words or so.



I do not feel that the following dialog:

"How did you destroy all but a remnant of the Dark Lord?"

Harry hesitated. "I Obliviated most of his memories and... sealed him, I guess is how wizards say it. Even if the seal breaks, he won't come back as himself."

Severus frowned briefly and then shrugged. "I suppose that is acceptable."

really fit with what Snape told sooner in the story:

"No," Severus said flatly. "The prophecy is not yet fulfilled. I would know if it were."

"Are you sure of that?"

"Yes, Potter. If the prophecy had already come true, I would understand it! I heard Trelawney's words, I remember Trelawney's voice, and if I knew the events that matched the prophecy, I would recognize them. What has already happened... does not fit." The Potions Master spoke with certainty.

I was expecting a more interesting reaction than just a shrug from Snape.

> He knows. The thought came to Harry, and he couldn't have said in words just what the Potions Master now knew; except that it was clear that Severus knew it.

The Dark Lord spoke the words "Hyakuju montauk" without pausing in his stride, accompanied by a jab of his wand; and Severus staggered before he lifelessly drew himself up beside the door once more.

"What -" Harry said, as he followed. "What did you -"

"Just fulfilling my obligation to my faithful servant. It shall not kill him, as I promised you." The Dark Lord laughed again.

I don't understand either of these. Though this in the mix and I still don't understand.

> I went to the Dark Lord intending to sell him the prophecy in exchange for Lily's love becoming mine, by whatever darkness was required to achieve it.

Severus shook his head. "Too many students would remember me as the evil Potions Master. No, Minerva. I will go someplace new, and take a new name, and find someone new to love."

I get the character arc "Snape's obsession was used by Dumbledore and Voldemort, but he has finally gotten over Lily and can move on" -- it's just these specifics I don't understand.

If I had to guess, Voldemort did something so Snape understands how Dumbledore manipulated him. Considering how pissed off Voldemort was that Dumbledore would do that, it seems likely that he would find a way to change that now that Dumbledore is gone.

Eh. I think Snape already understood that Dumbledore was manipulating him. From the interlude with the confessor:

“It's strange," Snape said quietly. "I have had two mentors, over the course of my days. Both were extraordinarily perceptive, and neither one ever told me the things I wasn't seeing. It's clear enough why the first said nothing, but the second..." Snape's face tightened. "I suppose I would have to be naive, to ask why he stayed silent."

This sentence just clunked for me:

There was so much to do, so many things, that even Headmistress McGonagall didn't seem to know where to start, and certainly not Harry.

"and certainly not with Harry", with Harry as the object of McGonagall's starting, or "and neither did Harry", as in "Harry didn't know where to start either"?

"and neither did Harry", as in "Harry didn't know where to start either"?

That was my interpretation.

I agree with the second, but I read it as ‘and Harry certainly did not’, which makes the actual phrasing seem slightly more justifiable than it otherwise would seem.

I hoped for more than one chapter of Hermione-ness because I like how EY portrays her, but Snape had also deserved a good ending.

We still get to hear what Hermione wanted to talk to Harry about before anyone else, right?

"Have you gone through puberty since we last spoke?"

Snape strikes me as a sort of a Ron situation. He's a character who has narrative weight because of cannon, but a comparatively small part in HMPMOR. That said, this was a fine sendoff.

I think Snape has a big part in HPMOR. At least he consumes a lot of narrative space. He essentially drives the whole hermione and the hero club arc, since if he didn't help them it would have been over fast. He does a lot to help Harry mature.

Smaller than in baseline, but still fairly significant. The fourth-most-important professor.

After Quirrell, Dumbledore, and McGonagall, I presume?

FYI, this is cannon. I think this is what you meant. /nitpick

"I think this is the beginning of a beautiful friendship."

Except for that leaving and changing identity thing. That might get in the way.

Someone else may have already come up with this interpretation, but I just wanted to get a prediction posted before the last chapter comes out.

Voldemort most likely had turned the diary of Roger Bacon into one of his horcruxes. The book was described as unusually durable, and it was given to Harry at a point in the story before Voldemort acquired the Resurrection Stone, so horcruxes would have worked only by touch. Needless to say, it was to his advantage to have one in Harry's possession, to be able to potentially take over the body of Tom Riddle v2.0 if the whole Quirrell thing didn't work out.

And now the diary is (supposedly) Hermione's horcrux too. Oh, dear. Since Voldemort wrote her into Harry's Vow as a required source of advice and restraint, he would have wanted to retain the option to influence that advice and force Harry away from dangerous decisions. So mixing horcruxes together in the same object might have been intended to give him the option to take over Hermione's body with access to her memories, if his plans failed to the extent of Harry surviving the night of the final exam.

With his personality now Obliviated, the mixing of souls might work in the other direction. My prediction for the final chapter is that Hermione has retained her personality but now has access, at some level, to Voldemort's accumulated magical lore, and possibly to things like passwords to his hidden caches of artifacts (since they'll eventually need to get the Resurrection Stone back to finally get the Hallows together).

This would be a neat last twist, opening a lot of possibilities for Harry and Hermione to kick off a collaboration on solving the problems of the universe in subsequent years. And the parallelism is elegant: the Girl-Who-Revived acquires a fragment of the vanquished Voldemort just as the Boy-Who-Lived originally did. We'll see if she gets a dark side too. ;-)

Word of god already said the diary wasn't supposed to be important at time Voldemort gave it to Harry. So it was probably just enchanted to be unusually durable.

HPMoR Snape reminds me of the Douglas Adams' Rain God. Trouble and sadness will follow him for as long as he lives, and then some. He'll leave a very unhappy ghost, too.

Maybe, maybe not? He's been making his own rain for a long time. We don't know what he'll be like when he isn't actively trying to be awful.