Professor McGonagall looked like she was in pain. "Alastor - but - will you teach the classes, if -" "Ha!" said Moody. "If I ever say yes to that question, check me for Polyjuice, because it's not me."

Did anyone else laugh out loud at that line? :-)

I was thinking that as of this chapter, Harry now had enough evidence to promote to attention the hypothesis that Quirrell is actually Voldemort. He has reason to believe that Voldemort has access to a mechanism which allows him to take control of people and give them a portion of his power, and Quirrell's apparent backstory entails his having undergone a conspicuous increase in apparent competence, much like that which Moody and Dumbledore suspect of having happened to Lockheart. And he has the assurances of the Order of the Pheonix that Voldemort was really smart, no, seriously smart, trust us, you're still underestimating him. And he knows Quirrell is heavily misanthropic and cavalier with people's lives, and also he went out of his way to remove Voldemort's premier servant from Azkaban, who might be useful to other enterprising wizards if she was taught some of the lore of Salazar Slytherin, but also, as Harry has been told, is a key component in restoring Voldemort to power.

But then it occurred to me that given the fact that Quirrell's sudden spike in competence in his backstory occurred while Voldemort was still around, not after his death, he would have to draw the conclusion that Quirrell was playing both sides back then. I've been operating under that assumption for a while, so I'm biased with respect to evaluating how obvious it should be given what Harry knows. This may be enough to drop the hypothesis below the attention-worthy threshold for Harry right now. But Harry does have the information to raise this particular question: if Quirrell is so smart, and was fighting against Voldemort, why didn't Voldemort lose, the way Harry thinks the Order of the Phoenix would have if they were up against a really creative and powerful wizard?

Primary piece of evidence against: Voldemort tried to kill Harry, Quirrell has passed up multiple opportunities to let Harry die. If it weren't for this, I'd think Harry was being a bit thick for not having considered the possibility already, but this is awfully strong counterevidence.

This chapter, and the update to Chapter 85, are both fantastic. I hadn't noticed until now that Moody is the avatar of being pessimistic enough that your expectations overshoot and undershoot reality appropriately often (in the same way that Fred and George are the avatar of Aumann's agreement theorem), and I'm wondering what other avatars I'm missing.

This won't exactly be a new observation, but one thing I really like about reading MoR is that some of the most important events involve characters updating their beliefs, and in pretty much any other story the only way this happens is when characters announce themselves or other characters doing this, e.g. "Aha! So it was you who killed Prince So-and-so! You traitor!" and instead MoR characters update their beliefs inside their heads like sensible people and the reader has to figure out the nature of the update for themselves. I don't think I've seen this happen in any other story I've read, it is a great rationality exercise, and I more or less completely missed it the first time I read through. (That is, I noticed Harry doing a lot of updating because it's text instead of subtext, but it didn't occur to me that I would understand the story better if I kept track of updates going on in minds other than Harry's.)

Now Mad-Eye Moody was turning slowly, always turning, surveying the graveyard of Little Hangleton. [...]

Moody didn't actually need to turn to survey the graveyard.

The Eye of Vance saw the full globe of the world in every direction around him, no matter where it was pointing.

But there was no particular reason to let a former Death Eater like Severus Snape know that.

Some time later:

"You see in all directions," Harry Potter said, that strange fierce light still in his gaze. "No matter where that eye is pointing, it sees everything around you."

Oops.

I'm a little surprised that HJPEV didn't immediately update his probabilities regarding Quirrell's motives in Azkaban with the new knowledge from Moody that "You've got to mean it. You've got to want someone dead, and not for the greater good, either.", which would seem to discredit the Defense Professor's excuse that "a curse which cannot be blocked and must be dodged is an indispensable tactic."

Harry is slowly updating on the evidence that the wizarding community is not as grossly incompetent as he originally believed.

I think I preferred the old version of 85 more than the new one. "The phoenix only comes once" seems a lot more made-up than Harry's original determination to abandon comic-book morality as soon as someone died, which felt very much in character.

86 is certainly interesting, even if it largely felt like a wrapping-up restatement of what we knew. That said, I loved the Moody duel, and after six months a bit of restatement is quite useful. Also, I'm torn between how to interpret Snape's last question - my first thought was that he was verifying the truth of a story he had been told("Your master tortured her, now join the light side already!" being the most likely), but upon rereading, I wonder if he was worried that she had been used as Horcrux fuel.

Harry needs to think more before he tells people things just because they ask. Just because somebody's not Quirrell, Harry, doesn't mean that their knowledge has no consequences!

One thing I really liked about this update is it helps explain why Harry hasn't figured out Quirrell = Voldemort yet. He's reasoning (perhaps without even having spelled it out in his head this way) that if Quirrell had been Voldemort, he would have won very quickly.

This is all fascinating, because it's a fairly good solution to the problem of "if Harry is so smart, why hasn't he figured out the solution to the problem that most of the audience has figured out by now?" I can't say I would have come up with that good of a solution to such a problem in any story I was writing.

That said, it seems like there are at least three conversations which could unravel the whole thing:

1. Harry learns enough about horcruxes to make the Pioneer Plaque connection.

2. Harry confesses about Azkaban, Dumbledore says "Harry, you fool!" and that's that.

3. Hermione tells Harry about her recent conversation with Quirrell, confirming David Monroe = Quirrell = the plotter and suggesting the possibility that Voldemort was toying with Magical Britain for the fun of it during the war.

CFAR could make very good use of a lot more money than this while starting up. I don’t work for the Center for Applied Rationality and they don’t pay me, but their work is sufficiently important that the Singularity Institute (which does pay me) has allowed me to offer to work on Methods full-time until the story is finished if HPMOR readers donate a total of $1M to CFAR.

That's quite the author's advance!

HP: Punch AM in snout to establish superiority.

Anyone else getting tired of this? Harry does it to everyone he meets, including Minerva and Hermione.