So, something from the sub-Reddit:

EY: If you throw a Transfigured object and de-Transfigure it, it continues moving at exactly the same velocity, regardless of momentum and kinetic energy. There are at least two good reasons for this, one of which is that, even in MoR, Special Relativity is simply the way reality is; you can add laws that violate conservation of momentum and even conservation of energy (though the latter requires the insanity of single-world QM, but then so does the Time-Turner), but in a Minkowskian universe the idea of a privileged frame of reference is too incoherent even for magic. The other reason is that if you didn't know about conservation of momentum or energy, of course you'd expect the object to continue with the same velocity.

My limited physics knowledge is failing me. Assuming that you stick with relativistic velocity transformations, why is conserving momentum problematic?

Ch 96 initial thoughts (no big spoilers):

I wonder if EY is aware of a couple of things: There are Muggles living in Godric's Hollow (canonically, Hogsmeade is the only all-Wizarding village in Britain, and at least one Muggle resident appears briefly in the books). The Potter family motto was first written by Paul of Tarsus (unless he was quoting somebody else, presumably long lost), the famous early Christian.

It is pretty sad how that quotation is interpreted canonically. Paul's original meaning is much closer to MoR!Harry's; although Paul's interpretation is softened by his faith in a deus ex machina, it was a faith that Paul may have sincerely believed (where most modern Christians, after 2000 years of disappointment, only believe that they believe).

I had this theory before the current arc, but updated towards it once it became more important to Harry in chapter 89.

In Humanism, Harry thinks about vanquishing future death, but that would not help the majority of the world's population (which has already died). What with the only known method of backwards time travel creating stable time loops, and with people already having died, this makes sense to a degree. But if he were to find a way to upload just prior to death, then technically everybody would have died, but in most ways that count they would not. As people have died more than six hours ago, this also seems impossible with known methods of time travel. However, Harry was (understandably) too distracted when learning about Time-Turners to notice that the six-hour limit could not possibly be fundamental. I believe I have a way around this limit, using only Time-Turners and Muggle understanding of physics. It does rely on the following assumptions:

1. Magic works very far away (many light-hours at least) from Earth
2. Time-Turners deposit you stationary w.r.t. Earth's rotating frame of reference.
3. Magic can reinforce Time-Turners and wizards to be able to withstand incredible accelerations (at least 2000 g)
4. Magic and science combined can maintain a space-worthy vessel at these accelerations
5. Time-Turners take you back the appropriate number of hours in whatever frame you happen to be in when you engage the Time-Turner.
6. Magic and science combined can create space suits that allow survival several light-years from Earth for extended periods of time OR devices that can maintain themselves in such conditions for extended periods of time and can operate Time-Turners.
7. Magic would allow the below scenario to play out (no DO NOT MESS WITH TIME notes). For safety, this should only be attempted after adding explicit protocols for those notes should they prove necessary; that's better than conjuring arbitrary obstacles with Time-Turners.
8. The below calculations are approximations based on my incomplete understanding of special relativity, but could almost certainly be improved by somebody with a better physical understanding than mine.

Not all of these conditions are strictly necessary, but the details of the situation would need to be modified to suit them better. I will now illustrate how to prove to somebody that you can go back in time more than six hours (specifically, six hours and five minutes); extending this to allow for remote unobservable uploading is left as an exercise to the reader.

1. Create a space ship traveling at 88.5% of the speed of light in uniform circular orbit of the Earth, matching the Earth's natural rotation direction and speed. This will require it to be 3.38 light-hours from Earth and accelerating at almost 2000 g, but we're already assuming we can do that.
2. On that ship, have somebody/something capable of receiving messages, using a Time-Turner, and sending messages after using said Time-Turner.
3. Find somebody to agree to this experiment, and to agree on a protocol. Verification can include hashing ("I believe one cannot reverse an MD4 hash, even with magic, in less than 6 hours"), trusted third party ("I doubt that Chief Warlock Dumbledore would lie about what time you gave him a message"), or any other scheme that everybody agrees on.
4. On Earth, get a means to listen to a light-speed message sent by the person/thing in step 2. When it receives a message, tell the person from step 3 and prepare verification, but do not tell the person from step 3 what the message is.
5. Have the person from step 3 wait six hours and one minute before deciding on a message to send, and have them give you this message.
6. Complete verification that the message was received when claimed. The person from step 3 now believes you sent a message back more than 6 hours.
7. Send the person/thing from step 2 the message at light speed.
8. Over three hours later, the person/thing from step 2 receives the message, goes back in time six hours (local reference frame)/13 hours (Earth reference frame), and sends it. Over three hours later, step 4 completes.

EDIT: Fixed the link for acceleration calculation by escaping parentheses

Chapter 96 spoilers (it's out; please read): The graveyard made me remember how canon implied that Voldemort was a descendant of the Peverelles as well, and how there was Peverelle tombstone there... I had a "Oh crap... no, this is the end of this arc; EY wouldn't have Voldemort show up there to use Peverelle bones in this chapter... right? I mean, there was supposed to be padding before the next arc..."

I couldn't help but wonder what Harry would think if he found out that inscription was also in the Bible (I forget which book; one of the apissles?)

(ETA: 1corenthians15:26.)

After sitting down and going over everything I know about this fic, I believe I've gotten a substantial way towards solving its puzzles. The long version is at my blog here, but here I'll just state without justification the prediction I've come up with:

Voldemort believes fate won't let him defeat Harry until Harry attains the power to vanquish him, which in this case means becoming powerful enough to destroy all of Voldemort's well-hidden horcruxes. And in fact, Harry will become that powerful, by using the differing conservation laws for magic and science to conduct conservation-law arbitrage. Voldemort's plan is to possess Harry once Harry has attained ultimate power, but Harry will prevent Voldemort from winning through complicated means involving multiple currently yet-to-be-fired Checkov's guns.

I recently started yet another re-read of HPMoR, and noticed something I don't think has been discussed before.

In chapter 1, Petunia is talking about Lily making her pretty (which I believe she did using a potion of eagle's splendor with the blueberries replaced by Thestral blood), and says

And Lily would tell me no, and make up the most ridiculous excuses, like the world would end if she were nice to her sister, or a centaur told her not to - the most ridiculous things, and I hated her for it.

I used to think that Lily just wanted to protect Petunia from the danger and possibly other reasons. However, after hearing the prophesy in Chapter 89, I'm updating in favor of Lily telling the truth as she understood it. Centaurs are, after all, great at divination, especially astrology (tangent: I've never understood how that can be used for predicting the future on Earth, because it seems like anybody for the last several hundred years could have then, in a vague way, predicted the entire course of human history at least until the Space Age) and may be able to see this coming. Usually astrology isn't the precise, at least not in canon HP, but when it predicts the destruction of the "very stars in heaven", it may be more precise (and the centaurs may care more).

Oh, I just figured something out:

Voldemort wants to see Harry's science textbooks because based on the prophecy he believes (or at least suspects) that Harry will have the power to destroy even the Pioneer Plaque horcrux, and he needs to figure out how that could possibly be.

Can't believe I didn't get that sooner.

Something I don't think anyone has commented on yet: exactly why is Harry in the permitted forest in Chapter 95? What is he looking for? This Harry has not previously shown a tendency to wander off into nature for peaceful relaxation. He's more of a library sort of guy, if he wants a place to quietly think and consider.

A little piece of evidence pointing to hypothesis "Harry had stolen Hermione's body".

"I care enough to make an actual effort" can be interpreted as "I already made an actual effort", and that was the interpretation that came to my mind on the first reading.

Also, this is very interesting:

The most likely prospect for disaster is a powerful wizard who, for whatever reason, cannot bring himself to halt as warning signs appear. Though he may speak much and loudly of caution, he will not be able to bring himself actually to halt.

And earlier:

Harry didn't venture anywhere near the border of the Forbidden Forest, since there was no reason to take the risk. He walked invisibly among the more ordinary life-forms of the permitted woods, wand in hand, a broomstick strapped to his back for easier access, just in case. He was not actually afraid; Harry thought it odd that he didn't feel afraid. The state of constant vigilance, readiness for fight or flight, failed to feel burdensome or even abnormal.

...told Professor McGonagall that he was currently talking to the Defense Professor in the woods outside Hogwarts (just in case anything happened to him)

It looks like Harry will be able to actually be very cautious as opposed to speak about being very cautious.

Maybe this story will not end in a complete disaster.

For those interested: Chapter 64 has a new omake, "Jasmine's Lamp".

Now I'm dying to see rational treatment of Mozenrath.

You know, the fellow who had a lot of raw magical power, and hence every problem looked to him like a nail in a desperate need to be blasted away with his gauntlet? The fellow whose ego was very inflated and sore, and the concept of "pretending to lose" was so alien to him that he had his ass kicked by a book? The fellow who was unable to think clearly while his place in dominance hierarchy was challenged by Aladdin because he cared about proving his worth more than about getting actual work done? The fellow who believed that other people had no use for him, and only way to make them helpful was to turn them into obedient zombies? The fellow who apparently knew many ancient places of power and pieces of forgotten magical lore yet fails to use them successfully?

Yeah, I want to see a rational treatment of this one. And don't think that we ought to give Aladdin a Death Star to make story balanced. He already has an unlimited supply of wish spells.

This is so contrived as to be almost silly, but I just realized that if you squint hard enough Sybill’s original prophecy might have referred to Harry as the Dark Lord and Quirrell as the one who “approaches”.

The one with the power to vanquish the Dark Lord approaches ... born to those who have thrice defied him, born as the seventh month dies ... and the Dark Lord will mark him as his equal, but he will have power the Dark Lord knows not ... and either must die at the hand of the other for neither can live while the other survives ... the one with the power to vanquish the Dark Lord will be born as the seventh month dies ...

The “Defense Professor” is a persona, and in chatting with Harry Quirrell basically claims that he becomes whoever he’s playing the role of. The prophecy could interpret the creation of that persona as “birth”. “Mark” is ambiguous enough (in English it could just mean “notice”), and besides, the prophecy doesn’t say when he will be marked. And he certainly has powers Harry knows not; his weird doomy link with Harry (which we just learned gives him partial access to Harry’s mind) being only the most obvious example, and remarkable from the fact that Harry doesn’t seem to ever think about it.

Again, it’s quite contrived, but it could be a nice twist to pull on your readers, though I assign a very low probability that Eliezer would do that given his statements.

Did I miss something, or do we still have very little idea about what the word substitution in Snape's remembrance of the prophecy means?

And Severus Snape drew a breath, and intoned, "FOR THOSE TWO DIFFERENT SPELLETS CANNOT EXIST IN THE SAME VULD."

versus

She couldn't imitate the deep, chilling tone of the original prophecy; and yet somehow that tone seemed to carry all the meaning. "The one with the power to vanquish the Dark Lord approaches... born to those who have thrice defied him, born as the seventh month dies..."

"And the Dark Lord shall mark him as his equal," came Severus's voice, making her jump within her chair. The Potions Master loomed tall by the fireplace. "But he shall have power the Dark Lord knows not... and either must destroy all but a remnant of the other, for those two different spirits cannot exist in the same world."

That last line Severus spoke with so much foreboding that it chilled her bones; it was almost like listening to Sybill Trelawney.

I didn't cry in "Humanism." I didn't cry in "Stanford Prison Experiment." I didn't even cry when Hermione died. But this chapter finally did it for me. "If I were the first person in the universe who ever really cared about someone, then I'd be honored to be that person." That's the kind of moral stand missing in any number of lectures and parables by supposed moral absolutists. It takes quite a bit of deviation from normal thinking to even really comprehend that emotion, let alone spontaneously describe it.

What I love best about HPMOR is that it could so easily have been a Kid Hero parody fic, and even though it skirts pretty close, especially in the earlier chapters, it is never quite a straight up parody. In fact, for all that Harry snarks about his life being one big fantasy cliche, HPMOR takes the Kid Hero genre deadly seriously and plays almost every trope completely straight. Sure, Harry doesn't rush headlong into every danger like most kid heroes, but that's a difference in method, not in spirit. He feels the weight of responsibility just like anyone else who was ever chosen, or chose themselves.

Far more than the science and even the rationality, I love HPMOR because it believes in heroes. Conversations like this one are why I'm not reading a textbook. One day, I'm going to catalog every single discussion about morality, duty, heroism, or wisdom. I genuinely think reading them often will make me a better person, or at least better at being good. So thank you, Eliezer. You really make fiction shine as a teaching medium

Some conjectures on the nature of magic, the invention of new spells, etc.:

1. Whatever makes magic work is basically mechanical but smart enough to be sensitive to human intentions.

2. It has to do something broadly comparable to simulating the universe.

3. It is equipped with defensive measures of one or more of the following kinds. (a) Some things -- e.g., certain kinds of escapades involving Time-Turners -- would require excessive, possibly infinite, amounts of computation, and it won't allow that. (b) Some things -- again, including Time-Turner abuse -- actually lead to contradictions. Maybe those are caught in advance and prevented, or maybe those simulations just end when the contradiction is reached. (c) There are deliberate countermeasures against anything that looks like it's trying to marshal too much power, in case it's an attempt at hacking the underlying computational substrate (or whatever it is that makes magic work).

4. That is one reason why inventing new spells is dangerous. You might accidentally produce a contradiction or an excessively expensive simulation, or you might do something that looks like an attempt at becoming a god, in which case you -- or your laboratory -- or your country -- or your universe -- is terminated with extreme prejudice.

5. It is also why the most powerful magics -- the rituals -- require permanent sacrifices: something that involves a permanent sacrifice is harder to apply recursively in some weird way that turns it into a Become God spell. (It's like the way that the class of functions you can compute using only loops whose number of iterations is bounded in advance is smaller and easier to prove things about than the class of all functions you can compute.)

6. Whatever-makes-magic-work wasn't programmed in advance with any particular spells, potions, etc.; it's a general-purpose magic substrate. All the specific things have been brought into being by human beings -- it's a gigantic game of Nomic. That is why, e.g., all the spells have names that were obviously thought up by humans.

7. The words, gestures, etc., are likewise basically under the control of the inventors. That is why they can be stupid things like "Wingardium Leviosa", or require you to say "Oogely boogely" with just the right timing. (Perhaps the precision required is up to the inventor, or perhaps whatever-makes-magic-work decides how much precision to require on the basis of how powerful the magic is.)

8. Bringing a new magic into being isn't fundamentally difficult [EDITED to add: that would explain why there is such a thing as "the usual evasions" when someone asks precocious questions about spell creation]; perhaps it just requires forming a certain sort of intention and then demonstrating what actions (etc.) are required to bring about the desired effect. The difficulty and danger come (a) from the protective measures already mentioned, (b) from the risk that when you tell whatever-makes-magic-happen what you want you might fail to be specific enough and get something that meets your stated spec but is disastrous, and (c) from restrictions like one I mention below.

9. Maybe the heritability of access to magic is itself a thing that was decided by (a much earlier generation of) humans, perhaps as a deliberate measure to limit the number and increase the cohesion of those designing new magics.

10. How would this sort of general-purpose Everything Machine likely be set up, so as not to produce a universe of total chaos as everyone starts inventing their own new spells? (Even assuming no one is able to do anything too destructive or internally inconsistent, on account of the sort of restrictions I already mentioned.) Probably by having a requirement that new spells be consistent with existing ones, in some rather broad sense of "consistent". That would be another reason why inventing new magic is difficult. It might also give another reason for things like the Interdict of Merlin: an opportunity for old magic to be "garbage-collected", freeing up regions of possible-magic-space for new generations to explore.

I don't assign a super-high probability to any of these, but I find each more plausible than any other similarly-specific alternative I've thought of.

(This pertains to an earlier chapter, but discussion in its thread seems to have died down. Anyone got strong opinions on the proper etiquette in that situation?)

In chapter 91, we are told

• that Harry tried to cast the Patronus charm (to ask his Patronus to go to Hermione) but "[t]he spell hadn't worked though";
• that when McGonagall needed to send a message to Dumbledore "[h]er first try at casting the Patronus failed".

Now, given the circumstances, it's not that surprising that either of them had trouble with that particular charm. But isn't it odd that Harry didn't just try again? And we're told that for McGonagall "[i]t wasn't the first time she'd done it so, but she seemed to have lost some of the knack".

Are we to infer that there's some special Patronus-related weirdness going on? Or is it just ordinary grief and upset?

[EDITED to fix a trivial and tangential mistake.]

I'm repeatedly seeing 'Monroe' spelled as 'Munroe'. Is this due to a disagreement about how the name should be spelled, a common spelling error that has perpetuated in these forums, or is it a shorthand reference to some prior discussions or concepts which I'm thus missing in my reading on these discussions?

Quirrell's dialog in this chapter has me thinking again about what exactly he did wrong, as David Munroe. I wonder if Eliezer thought that through as well as he should have, being a little too eager to show off the character's flawed understanding of human nature. From chapter 34:

Professor Quirrell leaned forward at the podium, his voice now filled with a grim intensity. His right hand stretched out, fingers open and spread. "Division is weakness," said the Defense Professor. His hand closed into a tight fist. "Unity is strength. The Dark Lord understood that well, whatever his other follies; and he used that understanding to create the one simple invention that made him the most terrible Dark Lord in history. Your parents faced one Dark Lord. And fifty Death Eaters who were perfectly unified, knowing that any breach of their loyalty would be punished by death, that any slack or incompetence would be punished by pain. None could escape the Dark Lord's grasp once they took his Mark. And the Death Eaters agreed to take that terrible Mark because they knew that once they took it, they would be united, facing a divided land. One Dark Lord and fifty Death Eaters would have defeated an entire country, by the power of the Dark Mark."

Professor Quirrell's voice was bleak and hard. "Your parents could have fought back in kind. They did not. There was a man named Yermy Wibble who called upon the nation to institute a draft, though he did not quite have vision enough to propose a Mark of Britain. Yermy Wibble knew what would happen to him; he hoped his death would inspire others. So the Dark Lord took his family for good measure. Their empty skins inspired nothing but fear, and no one dared to speak again. And your parents would have faced the consequences of their despicable cowardice, if not for being saved by a one-year-old boy." Professor Quirrell's face showed full contempt. "A dramatist would have called that a dei ex machina, for they did nothing to earn their salvation. He-Who-Must-Not-Be-Named may not have deserved to win, but make no doubt of it, your parents deserved to lose."

Amelia Bones' later dialog suggests he was giving similar speeches as David Munroe.

Now the thing to notice here is that Voldemort's policies for troop discipline were really not all that exceptional. Lots of armies have had a policy of executing traitors and deserters. A policy of using torture to punish any slack may be hard to find, at least in the modern world, but I think if you go back a couple centuries you'd find militaries using flogging to punish minor infractions. The way the Dark Mark is described here suggests it works slightly different than canon, in that it acts as a magical tracking device whether the bearer deliberately signals Voldemort or not. Obviously no real world military does that, but if it were possible to cheaply put magical tracking spells on soldiers in the real world, it wouldn't be surprising to see militaries using them to discourage desertion. (In fact, I wouldn't be surprised if there were already a proposal floating around DARPA to put tracking implants in soldiers. For their own good, ya know, so they can be rescued if they go missing.)

Insofar as we can give a sensible account of what "Munroe" did wrong, we might attribute it to bad marketing: pitching it as, "hey let's do what the Death Eaters are doing!" rather than, "we need to do what any country would do in wartime." Even a cynic should be able to understand people's aversion to the appearance of imitating like Death Eaters, and respond by providing would-be followers with rationalizations for why they're totally different than the Death Earters. Also, from later chapters it sounds like "Munroe" may have been angling to be made magical dictator for life right away. A more sensible approach would have been to first ask to be made temporary dictator, like the original Roman dictators, and then find a way to make the crisis permanent, justifying a permanent dictatorship.

I am confused. You know how Dumbledore expresses several times to McGonagall his worry that he might be the Dark Lord Harry will need to face? I mostly thought this was simply guilt from having had to make lots of difficult decisions.

But I’ve been re-reading some older chapters today, and I noticed this (ch. 84):

“Indeed—indeed—that will be necessary and more than necessary, if the Dark Lord that Harry must defeat to come into his power is not Voldemort after all—”

“Not this again!” Minerva said. “Albus, it was You-Know-Who, not you, who marked Harry as his equal. There is no possible way that the prophecy could be talking about you!”

The old wizard nodded, but his eyes still seemed distant, fixed only on the road ahead.

What Minerva says sounds a lot like foreshadowing. More specifically, standard dramatic logic would suggest that it was actually Dumbledore who gave Harry the mark, thus justifying D’s fears and making Minerva’s reasoning exactly wrong on the point she is most sure about. There’s plenty suspicious about the “standard story” of what happened that night to allow it, and nothing else I know about Dumbledore sounds like something that would cause serious Dark-Dumbledore worries.

But that doesn’t seem to make sense at all with the rest of the story. Am I just reading too much because of theories I read here?

Piece of meta info:

V'ir vagebqhprq n grrantr sevraq gb UCZBE. Ure cevbe ernqvat sbphf fheebhaqf Qvpxraf naq Nhfgra naq gur yvxr. Fur unfa'g ernq YJ lrg. Fur'f whfg ernq gur arj puncgre. Univat abg ernq gur bayvar qvfphffvbaf be Nhgube'f Abgrf jungfbrire, fur qbrf abg xabj nobhg Ibyqrzbeg.

Vg vf bayl ng gur raq bs guvf, Puncgre 95, gung fur unf gubhtug hc gur cbffvovyvgl frevbhfyl.

Znal crbcyr unir orra jbaqrevat jul Uneel unfa'g znqr gur pbaarpgvba, naq V jnagrq gb funer guvf qngn cbvag bs fbzrbar ryfr jub qvqa'g unir gur Jbeq bs Tbq. Bs pbhefr, fur vfa'g Engvbanyvfg!Uneel, ohg gur qngn vf vagrerfgvat.

I am amazed that Eliezer managed to take Rowling's most corny idea and made it non-corny: "The power that the Dark Lord knows not" is, after all, none other than the power of true love. And it is a mighty power not because of a hokey magical force attached to it, but because someone who feels it in addition to being rational is motivated to reshape the universe. "Power comes from having something to protect."

It is still unclear how horcruxes would fit into the HPMOR universe given the premise that souls do not exist. Here are some thoughts and conjectures revolving around the postulate that horcruxes are complete memory/personality backups:

1. To recreate one's identity, there has to be more than just replication of memories. There also has to be a way to replicate the 'software' that governs our thought processes. Removing the limitations and shortcuts that our physical brain has in place would undoubtedly remove lots of mental biases (making us hyper-rational) but also raise the question of whether the resulting entity will really be 'us' or just well approximated copies of us (a well explored topic in the transcendent pony fic).

2. The very possibility of possession (as evidenced in the zombie Quirrell) gives evidence in favor of the possibility to project one's mind outside one's original body and still be able to retain the capacity to not only have semblance of life (a la magical portraits and ghosts), but to also be able to learn new information and retain it (i.e. grow) and interact meaningfully with the environment.

3. Assuming away the whole issue of whether one's identity can be virtually encapsulated independent of our biological hardware, this would require careful copy control (lest there be multiple versions of you running around, raising the question of which one is the 'real' you, explored comedically in one of robst's fanfics). Is Harry an incomplete horcrux, retaining Voldemort's post-transcendent software (hyper-rationality), but not his memories, i.e. a failure of copy control? (He clearly didn't inherit his rationality from biological parents?)

4. Magic in potterverse directly interacts with mind. So magic is capable of storing information, including memories, software, etc?

Since Voldemort has already gone through the process, he already knows what's involved.

On the 'starfield' spell:

Are we seeing the stars from the perspective of the Voyager probe?

For those wondering about this:

It has been three hundred and twenty-three years since the country of magical Italy was ruined by one man's folly.

323 years before 1992, this happened:

Etna's most destructive eruption since 122 BC started on 11 March 1669 and produced lava flows that destroyed at least 10 villages on its southern flank before reaching the city walls of the town of Catania five weeks later, on 15 April. The lava was largely diverted by these walls into the sea to the south of the city, filling the harbour of Catania. A small portion of lava eventually broke through a fragile section of the city walls on the western side of Catania and destroyed a few buildings before stopping in the rear of the Benedictine monastery, without reaching the centre of the town.

That's probably also what's referenced later on:

There is much literary wisdom in those stories. It is born of harsh experience and cities of ash.

(though it's pretty likely that in HPMOR-verse, all volcano eruptions, earthquakes, tsunamis, etc. are caused by Magic Gone Wrong)

But the fallen figure flinched away from Harry, and then slowly began crawl to away from him, in the general direction of the distant castle.

"Don't turn into a giant snake. That never helps."

Typo: "to away from him". (Same typo at hpmor.com and fanfiction.net.)

Another question: can we try to nail down Voldemort's body-management strategy (for lack of a better term)?

I've been assuming that Voldemort possessed Quirrell shortly before the beginning of the Hogwarts school year, and the dark magic he used is only good for about a year before it "uses up" the possessed body in some sense. (Killing it, rendering it an un-possessable vegetable, something like that.)

But after thinking about this hard, I'm not so sure about that. Maybe the degredation in that body's condition is due to being in constant close proximity to Harry Potter, or something. Also, that may not even be Quirrell's body, Quirrell may be long dead and this is just some poor schmuck Voldemort decided he could pass off as Quirrell.

I assume Voldemort has a backup plan, in case his plans for Harry do not come to fruition this year.

Going back in time, what was going on when Voldemort was also, simultaneously, David Munroe? It seems he was planning on using the Munroe persona for many years, so he can't have used the same method he used for the Quirrell-body. What if the Munroe body was his original body, and he was just counting on years of aging to prevent people who knew him as Tom Riddle from recognizing him?

We may safely assume Voldemort used different facial features for Voldemort and Munroe. I don't know if it's been explicitly stated in HPMOR if Voldemort (as Voldemort) was disfigured as he was in canon, but it seems likely. However, I doubt the disfigurement was an unintentional side-effect of dark rituals, as in canon, because Voldemort had no trouble appearing as Munroe. More likely, it was a deliberate choice, to make the villain he set up for himself to defeat as Munroe as evil-looking as possible. One possibility is that this was not a second body, but the same body as the Munroe body, shape-shifted.

I assume what happened on the night of Harry's parents' death went exactly as planned for Voldemort. While Voldemort could have been betting on his ability to resurrect via horcruxes, it's not clear what going there would accomplish. More likely, he either (1) did not die (2) sort of died, but already had a second body ready to go so he wouldn't have to waste time gathering his power to resurrect.

If he had two different bodies for the Voldemort and Munroe identities, it's possible he kept the Munroe body in reserve upon retiring that identity, deliberately disposed of the Voldemort body shortly after or as part of whatever he did to Harry, and then went back to using the Munroe body secretly as he prepared for Stage 2 (to be executed when Harry became old enough to attend Hogwarts.) I wonder if the place he goes when he leaves the Quirrell body is back to the Munroe body.

Quirrell seems to have been counterfactually mugged by hearing the prophecy of the end of the world...which would mean his decision theory, and psychological commitment to it, are very advanced.

Assume Quirrell believes that the only possible explanation of the prophecy he heard is that the apocalypse is nigh. This makes sense: prophecies don't occur for trivial events like a visitor to Hogwarts destroying books in the library named "Stars in Heaven" and "The World," and the idea of "the end of the world" being a eucatastrophe hasn't occurred to him. Assume Quirrell believes that prophecies are inevitable once spoken. Then why is Quirrell bothering to try to save the world?

Given that he hears the prophecy, Quirrell can either try T or not try ~T to avert it. Given that he tries, Quirrell is either capable C or incapable ~C of averting it. If T and C, by inevitability Quirrell will never hear the prophecy, which means that it is less likely the end of the world will occur (massive events always produce a prophecy that is heard by a wizard, so either Time finds some way to stop the end of the world or someone else hears it but fails to avert it). Say the end of the world causes -100 utility to Quirrell, and trying to stop it causes -1 utility. Then if C, a Quirrell that would try never hears the prophecy, so he never loses any utility, while a Quirrell that would not try hears the prophecy, goes out in a blaze of hedonism rather than fighting the inevitable, and loses 100 utility from the end of the world. Unfortunately, the actual world is the ~C world, where T brings -101 utility and ~T brings -100. So T looks like an irrational choice, but actually maximizes Quirrell's utility across counterfactuals.

This isn't the only explanation for Quirrell's actions; he could just prefer to go out fighting, or be betting on the slim chance that prophecies actually can be averted, or just trying to delay the end of the world as long as possible, or acting on other, weirder motives. But it's an interesting illustration of how alien a being that has truly internalized a really sophisticated decision theory might be.

Dumbledore gets the map from the twins, doesn't give it back and the twins don't remember about it anymore. So, we know who'd obliviated the twins. However, we don't know the results of D's "find Tom Riddle" order... Also, the twins must've known about Harry's time travels by way of the map?

A while ago Mitchell Porter wrote that Robin Hanson often makes arguments like:

People claim that they want to be smart and would like to be smarter. But if you stand on your head, blood pools in your brain, providing more oxygen, and thus improving your cognitive function. Yet people spend hardly any time standing on their heads. Does this mean that they don't really want to be smarter?

Quirrel is being even more Hansonion than usual in #95, arguing that other people not trying to raise their friends from the dead means they don't care about their friends.

Professor Quirrell took a small step to the left, a step forward, another to the right. He tilted his head with a look of calculation, and then he walked almost directly towards where Harry stood, halted a few paces off with the sense of doom enflamed to the height of bearability.

Nice, Quirrell is tracking Harry by checking in which direction the sense of doom becomes stronger.

I hereby rechristen "the sense of doom" to "the sensor of doom".

Edit: "But what do Muggles know of true power? It is not them who frightens me now. It is you." Typo, should be 'frighten'.

Edit 2: "I could name a dozen examples in Muggle novels of people driven to resurrect their dead friends. The authors of those stories clearly understood exactly how I feel about Hermione. Though you wouldn't have read them, I guess... maybe Orpheus and Eurydice?" -- Aah, what a lost chance to break the fourth wall and cite HPMOR as an example!

On Quirrell's theory of human nature:

It seems to me that in general, his theory yields pretty accurate predictions, and to see what's wrong with it you probably need to know some evolutionary psychology; Eliezer's Adaptation-Executers, not Fitness-Maximizers. Evolution is going to favor genes for convincingly acting like you care about your friends without incurring too many costs for their sake. Yeah, it's also going to favor genes for seeing through easily faked signals, but to the extent that people can get away with it, it's going to favor genes for seeming to care about your friends without incurring the costs that would go along with that. The twist is that evolution while evolution produces behaviors that tend in that direction, it doesn't produce creatures who follow the strategies exactly, or consciously. The result is people who actually care about their friends... even if they very often don't act like it.

I just realized that Harry does not worry about Hermione's body disappearing anywhere I can remember in this chapter, which tells me he either knows exactly what's going on, or he plans to ignore the direct route and just become god, and thus it doesn't matter.

Or maybe find a worthy Muggleborn in a country that didn't identify Muggleborn children, and tell them some extensive lies, fake up a surrounding story and corresponding evidence, so that, from the very beginning, they'd have a different idea of what magic could do.

Pretty sure this is Jean-Jacques Rousseau's strategy in Emile. Albeit for social-sexual development, instead of magic.