(The HPMOR discussion thread after this one is here.)

This is a new thread to discuss Eliezer Yudkowsky's Harry Potter and the Methods of Rationality and anything related to it. There haven't been any chapters recently, but it looks like there are a bunch in the pipeline and the old thread is nearing 700 comments. The latest chapter as of 7th March 2012 is Ch. 77.

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.

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.

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Yudkowsky which is not supposed to be publicly available (which includes public statements by Eliezer that have been retracted).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

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I see also that the theories about Santa Claus's identity are equally as varied as the ones about Mr. Hat & Cloak. My take on this is similar to my take on H&C: we're meant to understand that Santa Claus is simply Dumbledore.

  • Santa Claus had possession of the Cloak of Invisibility and passed it down to Harry, who Santa somehow knew was its rightful heir.
  • Santa Claus also somehow knows about the full misdeeds of James Potter, many of which are known to no one else.
  • Santa Claus has the political and magical power to create Portkeys on the Hogwarts grounds and get away with it.
  • Santa Claus has deep insight into Dumbledore's true motives, and makes true statements about him without ever stating that Dumbledore is a different person.
  • Santa Claus knows little about Quirrell, but doesn't trust him.
  • Santa Claus says that he cares about Harry Potter's well being and wants him to be more careful in the future.

The only person we know for whom all the above facts are true is Dumbledore.

However, the "S" who left notes for Hermione is not Santa Claus. It's Severus Snape, who we know for a fact was the mysterious person helping SPHEW in its mission. The two signatures happen ... (read more)

I congratulate you on your 100% accurate pre-hoc explanation.

Sirius Black fits Santa as well, if not better, though most of what we know about Sirius comes from Cannon. * In Cannon Dumbledore had possession of The Invisibility Cloak when the Potters were killed, but he didn't necessarily keep it. This wasn't mentioned in books 1-5 though, so EY is probably unaware of that detail. * James' best friend Sirius knows James' misdeeds better than anyone besides James himself, and is much more likely to speak proudly of them than Dumbledore. * The Portkey doesn't have to have been made by Santa - it could have been made by anyone at the Salem Witches' Institute. And it doesn't work on the Hogwarts grounds. * Santa Claus claimed Dumbledore would keep The Invisibility Cloak if he ever got his hands on it, which was completely wrong, and a rather insane thing to say if it's Dumbledore (which doesn't prevent it from being Dumbledore, but still...) * Sirius wouldn't know anything about Quirrell. Dumbledore presumably researched him before offering him the DA job. Neither would trust him. * As Harry's godfather, Sirius would care a great deal about Harry.
There is also the Meta level to consider. Sirius Black is a major fixture of Harry Potter canon. He has not yet been featured or brushed off yet (eg the Weasleys). Every other major player from the first books has been given screentime so far. It seems incredibly unlikely for Sirius to make it to chapter 78 without a showing in one form or another.
I am pretty sure Santa is someone who works / lives in Hogwarts. Outsiders are not supposed to enter on their own. The bit about not trusting Dumbledore makes sense, even if the cloak came from him, since it allows Dumbledore to show off how trustworthy he is with little effort. And he can check how well Harry can keep a secret.
One thing i Just wanted to point out, Mr. Hat&Cloak (or, as Hermione calls him, Mr. Extremely Shifty Guy) appears to shape-shift when talking to her. Has anyone considered that he could be a manifestation of Tonks? Thats a bit far fetched, but whoever he is, he either can shape-shift, OR create illusions to make it look like he does.
But why would Dumbledore give Harry a Portkey in the first place? What reason could he have for giving Harry a route out of Hogwarts?

Nothing says the Portkey goes where it says it does. It could be a reasonably good test of "Harry Potter is desperately seeking a way out" if one just monitored his arrival in the destination.

Ch 78 You know, of all the things in the chapter, the law of Potion-Making seems the most important, by far - if I understand it correctly, it has staggering implications.

It's clear that you can extract more than purely physical processes from ingredients - since we have potions that bestow even entirely abstract concepts like luck(and canon!Snape claimed to be capable of brewing fame and glory, I'm unsure if MoR!Snape claimed the same).

So, could you, say, take a CD with some software on it and use it as a Potions ingredient in order to extract the mental work that went into programming that software, creating a Potion of Excellent Programming or something? Or, even better - could you take a copy of some brilliant scientific research paper, extract the brilliant scientific genius out of it and use the resulting Potion in order to create an even more brilliant scientific breakthrough? That's godhood in one shot right there.

I also have to wonder how Potion-Making interacts with the Mind Projection Fallacy. If you use a video game as an ingredient, can you create a Potion of Fun out of the video game or no? Fun isn't an inherent property of video games, it's in the minds of the players.

Might explain all those Nazi book-burnings. Grindelwald's human allies weren't just providing human sacrifices.

My intuition, my sense of fairness, says that you can't get back the work required to create information without sacrificing an appreciable fraction of the number of extant copies of that information.

I would guess that Magic and the Mind Projection Fallacy are sittin' in a tree, K-I-S-S-I-N-G.

You can make copies of books and of software CDs very cheaply. Given a law of conservation, it can't be the case that destroying (sacrificing) a cheap copy would gain you powerful results, or else you could generate infinite resources very quickly (and wizards would realize this).

Maybe destroying the last extant copy of a software would achieve the effect. One wonders what great magic was fueled by the burning of the Library of Alexandria.

True, using copies to achieve that kind of power doesn't seem to make much sense - the law even says that you can get as much... let's call it "work" out of the ingredient as was "invested". It's true that there isn't much of an investment of resources in copies. So, forget the copies, let's use the originals. For example, could you take Einstein's original notes/notebooks(copying them beforehand, of course, so that you don't lose information), liquefy them into a Scientific Breakthrough Potion and use that Potion to quickly figure another brilliant breakthrough? That's the kind of thing I'm wondering about.

If this were the case, could Hermione sacrifice the paper marked 42 for a Potion of Humanism?

Or if Harry wrote down his thesis on Partial Transfiguration, Hermione could make a potion from that (without reading it), and write down whatever discovery she made under the influence of the Breaking the Laws of Magic Potion, which Harry could then use to make a potion...

No, because the notebooks do not "contain" the work Einstein did, Einstein's brain contains it. So you'd need the living brain of a scientist as brilliant as Einstein. Which may not be that difficult; Einstein was good but he was also lucky - he glommed onto exactly the right Big Problem at exactly the right time. It's quite possible that there are any number of equally-brilliant scientists alive today who just happened never to find their Big Problem. The point remains, however, that paper and notebooks are not sufficient, you need the brain which actually contains the comprehension. Moreover, since magic works by sensible-to-humans laws in the MoRverse, even if you copied the brain you'd have to use the original in the potion, and you only have one of those. The reason being, the copy hasn't "done the work" even though it contains the comprehension; and you can only get back out the work that was put in. This of course makes no sense, information should be information, but the laws of magic were apparently designed by a human.
Not necessary living. And Einstein's brain just happens to be preserved. In fact, it sounds very much like people quarreled over magical ingridients:
Or the same entity (not Azatoth) designed or modified both humans and the laws of magic.
Or perhaps the original diary of Sir Francis Bacon?
For it to be "fair" destruction of General Relativity you'll need the information to be destroyed, not container. So everybody everywhere in the universe would need to forget it AND you need to destroy every physic book with it, and wikipedia, etc, etc.
Well, "invested" seems to be interpreted weirdly by magic. Sunlight is stored in acorns in the form of chemical energy, and the light you could get from a few acorns is about the same amount you'd get by burning them thoroughly (say, in oxygen flux). The effects of Harry's potion seemed to be much more powerful than that, I'd say of the level of the light absorbed by the entire oak for a year or more. So it seems like you can get something like "the entire effort" spent to produce something (grow a tree for a year) from just some of the results (nothing indicates they got all or even most acorns from a single tree).
Actually, I don't find the amount of light released to be far from the mark. Burning several pounds of acorns and converting all the released energy into light would be ridiculous - consider that even at a MJ per kilo, you're looking at a million watts worth of incandescent bulbs for 50-100 seconds (incandescents are only 1-2% efficient IIRC.)
Actually, you might be right. I was thinking in terms of a pound or so of gasoline deflagrating, which would be bright if it happened really quickly but doesn't seem blinding when stretched over more than ten seconds (intuitions based on fires and movie explosions being much brighter than the real stuff). But I was ignoring the spectral focus and the lack of kinetic energy released. Lets's see: Wikipedia gives wood (red oak!) 14.89 MJ per kilogram. Spent over 60 seconds (the Chaos-Dragon battle is said to have lasted "a lot longer" than "very quickly") that would generate 248 kW. Direct sunlight is quoted at reaching 130,000 lux, but even with an albedo near 1 (conservativ, snow reaches .9) that's not bright enough to make you unable to see by shielding your eyes with an arm (based on recent experience of noon sun while skiing). So I'd guess the cauldrons would have to generate more than 1M lux for the effects described (maybe significantly more, brightness is nonlinear). Assuming conservatively that the illuminated surfaces in a battle to be a square at least twenty meters on the side, that's 400 square meters and 400M lumens. With pure green light (the brightest kind) you get 683 lumens/W. But the cauldrons gave everything except green, so let's say 400 lumens per W. So you'd need about 1MW of power to light a square of snow 20m on the side to ten times brightest daylight during one minute, or about four kilograms of red oak. Given that the illuminated area is probably much larger (including light lost to the sky), it's surface has much lower albedo (grass: .25, bare soil: .17, deciduous trees: .15 to .18), acorns probably take more than a gallon per four kilos (and I doubt they had time to gather ten kilos of acorns for both cauldrons), and that the quoted figures for oak involve burning with oxygen, I'd say that the energy in the acorns themselves falls short by at least an order of magnitude. But then again my errors are likely more than an order of magni
Obviously it powered first Julius Caesar's conquest of the Mediterranean, and then Islam's conquest of North Africa.

Another thought: write down a description of a complex magical principle that you understand, but that the interdict of merlin would prevent someone else who was reading it from understanding. Use the parchment you wrote on as an ingredient in a potion to make a potion with the mental work needed to discover/comprehend that principle.

Poof, Interdict of Merlin loses its teeth entirely. :)

Another thought that occurred to me: Felix Felicis. No wonder it's hard to brew. Only way you could brew it is if you literally got lucky in the process of brewing it, by chance, so that you can take that "chance" and put it into the potion.

(hrm... might be able to automate the process of making Felix: Have a machine that keeps mixing the ingredients many times in parallel, ie, many "potential potions", and in the process does something like for each potential potion, has a coin (or some random bit source which can then be physically placed in the potion) which it flips a 100 times. It also tracks the results, and when one of the coins comes up all heads, it drops it into the candidate potion then calls up the wizard to complete the potion.)

Oh, and MoR!Snape did claim you could b... (read more)

Hee hee. But no, I didn't mean a "potion of cleverness", I simply mean "be clever and invent a potion. Then use that potion as an ingredient to place the quality of the mental work of inventing a potion into a potion... then use that potion as an ingredient, etc.."

And actually, we know Harry meant to investigate mental magic, but we're not sure if he ever got around to it. (And, of course, there is Rowena's Diadem, which would seem to be an intelligence augmentation device. If that's in MoR, Harry's got to do something with it at some point. (But then, harry hasn't yet really jumped onto the existence of the Philosopher's Stone, so... well, I guess everyone here's already waiting for when he notices that and Epic Rages at the wizarding world along the lines of "you mean you already know how... you... ARGH!")

And we'd expect Ravenclaw members to already be using any clever potions or at least have rules against them (either imposed by the school or by themselves as 'cheating'). In canon, they all know about the Ravenclaw diadem which is supposed to make you more clever. So it's reasonable if there were any such thing, Harry would have been told about it (everyone knowing his interest in self-improvement or being more clever), heard of it, or read about it by now.
Yes, because people want Harry Potter to be smarter than he is.
If it existed and was semi-public knowledge, then Lucius would have made a priority of acquiring some for Draco.
Who says he didn't? I notice that Draco is unusually bright, as are Crabbe and Goyle. It would certainly be convenient for the Malfoys if the youngest sons of all three families were significantly above average....
Draco doesn't even need to know about this.
^ Truth.
On the topic of potion invention, what ever happened to the cloak from the dementor Harry killed? Based on the rules of potions given so far, that could probably make a nice Potion of the True Patronus™.
Or a potion of instant death if it instead stored the decay effect from the dementor.
That's so easy to do you don't even need magic.
I'd imagine that would be determined by the other ingredients and stirring patterns. It could also be used to make someone invisible to dementors, immune to the effects of dementors, temporarily unkillable, give off their own dementor-like aura, or just look like a dementor. Depending on what the other rules are, that cloak could be very valuable.
Testing which potion we got by such and such stirring pattern would be fun. You give it to your hero and he is instantly dead. Or you give it to some criminal sentenced to death/Azkaban and he becomes unkillable for a month, or invisible to Dementors :) Or you give it to rat and nothing happens - you try to kill the rat and he's killed - maybe that was potion that makes you invisible to dementors?
That sounds a lot like modern drug testing, actually...
I think you would need a remnant of the destroyed dementor itself, not just a cloak a dementor happened to be wearing when you killed it, and I don't think dementors leave anything behind when you kill them.
Either Dumbledore or Quirrel took it, or it's long since locked away in the Department of Mysteries. But yeah, as JoshuaZ points out, just as easily could be a Potion-of-Death. (Or heck, "potion-of-anthropomorphic-personification")
I guess Harry's got another reason to destroy more dementors. Also, I suspect the cloaks will have more than one use. Dragons blood apparently has twelve uses, after all.
Um. It's not like Dementors come with cloaks, you know. If cloaks-that-have-been-worn-by-Dementors were really valuable potions ingredients, there's lots of easier ways to get them than by destroying Dementors. The Aurors manage to get the things to put them on in the first place, after all.
Dementors are implied to cause their cloaks to rapidly deteriorate, so they probably don't last long. Maybe "living" dementors accept new cloaks, but don't let the people take the ones they're wearing any more than you'd let a stranger make off with your shirt.
Yes, but the magic that was used to acquire that particular cloak was capable of blinding/destroying dementors, so it should be possible to get that magic back out using the newly revealed rule of potions.
3Joshua Hobbes
I'm not so sure obtaining an object is the same as creating it. Using Accio on a potion-ingredient will not allow you to make a summoning Potion.
It's already established that obtaining a crushed ingredient will let you access the strength involved in crushing it. So obtaining an ingredient that had to be taken by invoking extreme powerful magic might let you access that...
Regarding possible ingredients of Felix Felicis, Malaclaw Venom bestows upon the victim an unnatural misfortune; maybe this effect can be reversed and exponentiated by the process of brewing, and thats the hard part? (EY knows about this; second flask in case you ever wondered what that did.)

This thread is a little silly, even by local standards. First of all, the fact that a potion can be no stronger than its ingredients doesn't imply that a potion will always be as strong as its ingredients -- there are probably all kinds of other restrictions on what can be effectively brewed. By way of analogy, most Volvo engines don't run at Carnot efficiencies and most split pea soups don't run at more than 0.01 efficiency.

Second, all of the canon/fanon magical ingredients are non-copiable...a feather or a squished animal is not like a CD or a video game or a piece of parchment. Perhaps you could use the original of a piece of parchment if you didn't keep a spare copy, but EV drops lots of clues -- potion conservation was apparently designed by someone who thought the universe was fair, potion brewing is a substitute for a small, safe sacrifice, etc. -- everyone who's trying to figure out how to make a potion out of costless intellectual property is playing a different game than the one Harry's playing.

Third, advanced electronics tend to malfunction in proximity to strong magical auras -- so far the most advanced Muggle artifact that's been successfully used to interact with wiza... (read more)

Wait, someone's calculated this?
As I interpreted it, potions are doubly bound. The ingredients only 'remember' as much of an affect (light, luck, heat, strength) as was put into them, but they're also constrained by magic. Everything is bound by Magic In, Magic Out. Hence the talk of potions requiring magical ingredients. Under this interpretation, it means that potions act only as a coiled spring or temporary battery. Sacrificing software would only be useful if you needed intelligence right then and couldn't afford the magic at the time; if you just wanted to be generally smarter, you would just continually cast intellect charms on yourself (or perform a ritual). This also fits in cannonically, with many of the most powerful potions (Polyjuice, Felix Felicis, Veritaserum) taking months to brew and providing short duration benefits.
So, I guess I missed something. What was the magical ingredient in Harry's potion of light?

Just because every potion in the two textbooks Harry looked at involved magical ingredients doesn't mean all potions require a magical ingredient. As I read it, Harry found the potion he used in a more obscure book suggested by Prof. McGonnagal or Flitwick, probably something like a wilderness survival guide. Converting acorns into a beacon would be pretty helpful for getting found by search parties.

It turns out the common Oak is actually a magical plant.
That's what the Druids thought, anyway, right?
From the story: This leaves me with two possibilities: 1) Harry invested the energy himself in the potion. Instead of just using his magic to release the ingredients' potential, he poured in the required magic from his own cores. 2) Harry can now create potions from any non-magical substance as if it were a magical substance. I believe option 1 is the correct one. First, Harry didn't play a part in the battle, probably because he was magically depleted. He's learned just as much dueling as Neville, and yet contributed nothing and died offscreen. Second, Harry wasn't rejoicing the next day and testing out a dozen different types of potions. He didn't act like someone who just uncovered a global victory condition or new branch of magic. Third, wizards would have discovered this if you could simply make potions without investing in magic of some kind. As the name of the chapter implies, Harry discovered a tradeoff, not a loophole.
The fact that the light was impossible to Finite suggests that Harry did tap the energy of the acorns. It's implied that the magical cost to the creator of making a potion is a minor cost to reshape the components. So, the potion taps the light stored in the acorns, and Harry's magic is tapped only to do the reshaping. Probably most magical potions use the magic of the magical ingredient to do most of the reshaping work, so the user only has to invest a tiny bit of magic, while a potion not involving any magical ingredients might require much more input from the creator for the reshaping. That would explain why Harry is drained, but also why the light can't easily be dispelled. The other critical limitation on potions is that you must known the stirring pattern and the recipe in general. Figuring out the stirring pattern is the sort of thing that gets you permanently turned into a cat. So, Harry does not have god-mode because he doesn't have the time or expertise to do all the potion experimentation necessary to invent new potions without blowing himself up; he's limited to potions with known (but possibly obscure) recipes.
The Finite charm was trained to be used en masse by an entire army. It's a brute force spell requiring lots of power to dispel it's opposing spell. The usefulness of the sunlight potion wasn't in it's raw magical strength, but how quickly it disabled it's opponents. He entertains either option, but he chose the more risky one that immediately finishes the battle. It merely needed to stand up to a handful of Finite spells, rather than a massed and coordinated dispel. I say it is the more risky one because he did in fact lose by choosing this option instead of brewing an invulnerability to sleep potion. If he could have chosen to make potions of any potency, he would have obviously chosen a certainly victorious spell of a risky spell. This is evidence towards him putting in the magic himself. In order to deduce the stirring pattern, he looked up a potion with the similar ingredients and the same spell function from a preexisting recipe. If potionmakers could make the same potion using non-magical ingredients, then why wouldn't any of them have already invented a potion with nonmagical ingredients unless there was a significant drawback?
I think this is almost certainly what harry actually discovered.The other option is simply too powerful. He can use the essence of acorns to lead his own magic to a place he does not know how to take it, but he still uses his own power to get there.
3Joshua Hobbes
There wasn't one, as he wasn't making something magical. He was making sunlight.
Sure. And the potion of fire breathing doesn't make anything magical, it just makes fire. It still requires Ashwinder eggs.
Not quite, I think it actually makes (well, regains) fire breathing, not just fire, just as Ashwinder eggs need fire breathing, not just fire or heat AFAIK. If only heat or fire was needed, a copper coin has lots of it (see the other example) and isn't magical in itself.
The copper coin example is arguably a magical ingredient: the text emphasizes that it stores the heat of the goblin forges, and I imagine that those are somehow magical in nature.
The sun features prominently in so many mythologies that I would be mildly surprised if sunlight didn't count as magical in some way.
As I understand it, there was no magical ingredient. Other potions stored and released the magical energy of their reagents, but Harry's potion stored and released the light energy that went into making the acorns.
I'm guessing he used some kind of magical plant, possibly even a magical oak tree, since the text does specifically say it's lucky that the battle takes place in the Forbidden Forest, where actually magical plants grow, as opposed to the regular non-forbidden forests surrounding the grounds which have only mundane plants.
0Joshua Hobbes
Wrong, wrong, wrong, wrong, wrong, wrong, wrong wrong.
I stand corrected.


It's not just about him not bothering to check whether he had a visa to Fuyuki city.

It's about him always having claimed to be a Slytherin.

Despite actually being... a Ravenclaw?

That doesn't sound like the kind of claim you could get away with it, and Quirrell should know that, but he still makes it, and... gets away with it?

Doesn't any current Hogwarts student have parents/relatives/family friends who knew Quirrell from his time back at school?

And it's blindingly, blitheringly obvious by this point that Quirrell is H&C. Too obvious.

Why would Quirrell orchestrate this in a way that ends in him being interrogated by the DMLE? Compare with his attempted Dementation of Harry.

In fact, the same thing would apply even if he weren't H&C. I'd expect him to have come up with a better way of handling it. One with more plausible deniability.

Conclusion: Quirrell planned to be interrogated by the DMLE. Quirrell planned to have his cover blown. Why? I haven't the slightest idea.

I still don't know what to make of the Ravenclaw thing, though.

Edit: Just checked to see if Quirrell had actually claimed to be in Slytherin instead of just implying it. Yes, he had.

Yes, I was in Slyth

... (read more)

Speculation on the Slytherin/Ravenclaw issue: Quirrell is a double impostor. He's Voldemort possessing a Slytherin (name unknown) and pretending to be that Slytherin pretending to be a Ravenclaw named Quirinus Quirrell. Dumbledore knows about one level of the masquerade, and accepts the explanation that the Slytherin of unknown name is a private person. Quirinus Quirrell may be an entirely constructed identity, although that would make it less likely for him to have failed to remember some of the details of it under interrogation.

Voldemort himself seems like a pretty artificial persona. I think it's better to think of both Voldemort and Quirrell as Riddle's inventions, not directly related to one another.

But why would he go out and tell all his students that he was a Slytherin? That's effectively admitting that he's an impostor. (Unless, of course, it is a purely constructed identity. In which case even the records about his time at Hogwarts would've had to be fabricated. In which case... Why would he pick Ravenclaw rather than Slytherin?)
I am noticeably confused. I think the simplest explanation for this mixup about Quirrel's house is that EY forgot that he'd said he was in Slytherin earlier.
The line about having been sorted into Ravenclaw could be as fake as the Fuyuki City thing, Scrimgeour's play. Quirrell's apparent failure could just be a way of getting temporarily detained, while Dumbedore's looking for Riddle and Harry wants his help. His cover could actually be pretty solid, so he'd just shrug off Scrimgeour's suspicions once it's time to go.
4Joshua Hobbes
I don't think he's worried by the Marauder's Map. If he knew it could expose him he'd have already taken it from Fred and George. Of course, there is no possible way that he does not have his exit from Hogwarts entirely planned out. But it's still April, so I don't think he plans on leaving quite yet.
He may not know of the Map's existence. He may be afraid of Dumbledore having some, possibly unknown to Quirrel, spells (or Hogwarts wards) for locating people by their names.
But no doubt Dumbledore will hold on to the map for when Quirrell returns. But seeing as he may well be (intentionally) blowing his cover, that may not be for some time.

Thanks, Eliezer, for unpausing one of my substrates!


Minor typo at the end of 78, repeated at the beginning of 79:

The Aurors swept toward him with swift strides, Auror Goryanof approaching from the other side of the Ravenclaw as though to block any escape...

Actual speculation: what did Dumbledore know or suspect when he hired Quirrell?

"If you consult Headmaster Dumbledore," said the Defense Professor, "you will find that he is well aware of this matter, and that I agreed to teach his Defense class on the explicit condition that no inquiry be made into my -"

What exactly was Dumbledore aware of? Merely that 'Quirrell' may have travelled without a visa (I guess this is illegal), or that he was an impostor? If the latter, why would Dumbledore hire him?

But if Dumbledore wasn't aware that Quirrell is an impostor, then Quirrell has made at least one foolish slip. During the interrogation, Scrimgeour says

"Born the 26th of September, 1955, to Quondia Quirrell, of an acknowledged tryst with Lirinus Lumblung..." intoned the Auror. "Sorted into Ravenclaw...

But way back in Chapter 16, Quirrell says

Yes, I was in Slytherin and I am offering to formulate a cunning plot on your behalf, if that is what it takes to accomplish your desire.


My reading of the visa thing was that the Auror made it up on the spot to confirm that Quirrell had no idea of what trips he had taken in the past, and is therefore an impostor. Although I don't understand why Quirrell, if impersonating someone, would fail to look up these simple facts.

Quirrell is smart, but he's not omnipotent. He's had so many lives, he doesn't even consider any of them to be his true persona. Quirrell is mentally disciplined, but it's possible that he could have simply forgotten or gotten facts mixed up, trying to hold so many personas in his head at one time.

I believe Dumbledore would have been a professor of the real Quirrell, so he must know it's an imposter he's hired. I suspect Quirrell fed him some convincing lie or another about his true identity.

Because Q is someone very good at what he is about to teach who does not want to have his identity public. Dumblodore wants a decent teacher - as has been pointed out many times - and is willing to put up with a lot to get him. Now weather Dumbledore knows the true identity of Q is a different question.
The magical world is a small world, Hogwarts is a small school, at least some parents of current Hogwarts students would have remembered that Quirrell was in Ravenclaw not Slytherin. I'm guessing this is an inadvertent mistake by Eliezer.

I brought the same thing up here.

I doubt Eliezer would forget that the major spokesperson of Slytherin in his fic is... well, Slytherin.

There's something else going on here.

I figure being referenced in the author's notes is enough to justify cross posting. I guess I'll find out if that's the case. (In the choice between not posting and posting without updating speculation, I decided to rationalize my sloth with a false dichotomy, maybe.)

pervenit pasta

Chapter 14: The Unknown and the Unknowable

HJPEV tells McGonagall about the message for Slytherin's Heir, refuses point-based reward, receives Time Turner, freaks the fuck out about receiving a time machine to treat his sleep disorder, has another 'you turned into a cat' moment, receives invisibility cloak from unknown person, learns what getting lost in Hogwarts entails, pranks himself, learns "There was something wrong with Harry Potter."

Chapter 21: Rationalization

Hermione deludes herself about why she likes beating HJPEV, chooses love, displays knowledge of Planning Fallacy, claims her prize; HJPEV creeps it up with Draco, claims Hermione as his own, traps Draco with promises of power, mentions that Draco should test the strength of muggleborn magic personally, agrees that human sacrifice is easier than changing his mind, establishes tradition of secrecy in the magical sciences, establishes ... (read more)

The prize was that Quirrell gets to teach students the killing curse.
Thank you. I've corrected the post.

Update March 12: He's reading HPMoR, thanks presumably to the 7+ fan reviews from LWers, tvtropers, and whatever you call an xkcd fan. Still no fan reviews for Luminosity or Hamlet and the Philosopher's Stone.

Damien Walter reviews sci-fi and fantasy for The Guardian. He's looking for weird, self-published online fiction to read over the next month, and he'll review the best ones he finds. He's just asked people to recommend stories in the comments to his latest article. If you want to see Methods of Rationality, Luminosity, or my Hamlet and the Philosopher's Stone reviewed in a respected newspaper (there is precedent!), please consider heading over there and posting a short review (one link per comment, you can comment more than once). Each of the three is a hard sell even by online fantasy standards, and I imagine it would help if a disinterested party vouched for them.

How about Three Worlds Collide?
Go for it if you want! I love the story, but I'm not sure how well it works as Rationality Outreach.

Jumping in time just 6 hours back indicates to me that in the computer that is simulating MoR universe data is kept with 6-hours long cache.

As to Atlantis - they found a way to get out of the box - one level up, and they've left some cheat-codes for people that are still in this simulation. That also explains why some very important figures (like Dumbledore) think MoR runs on stories - somebody outside of simulation changes the simulation accordingnly. Maybe this simulation purpose is to make the best stories?

Also explains why prophecy works for more than 6 hours into the future - because simulation has some invariants, that make for best stories, and seers can well, "see" them, but only for very important events, and only guess ral meaning of these predictions. Hence mysterious prophecies.

What it doesn't explain - why cheat codes are in latinised English.

It seems possible to me that MoR spells work a bit like the URLs for TvTropes pages. When a new spell is created, it is attached to an arbitrary incantation of the casters choosing. From then on, that incantation recalls that same set of effects no matter who performs it, like entering a URL into TvTropes to retrieve a page that someone else wrote, when just yesterday that URL led to a blank page. What I want to know is whether Atlantis was the origin of the system or merely the last society to have edit privileges. (Maybe they abused the system and destroyed themselves so whatever's running the simulation brought the banhammer down on the inhabitants of the MoR verse, and thus began the decline of magic?)
You're almost right. The actual explanation is that they're all fictional characters in a Harry Potter fanfic. Dumbledore knows this, or at least knows they're in a story. The purpose is indeed to make a good story, and one that teaches Methods of Rationality. Because it's a Harry Potter fanfic, and in the original Harry Potter series, the spells were in Latinized English, probably because Latin has an ancient mystical aura for readers in fantasy tradition.
Oh Blueberry, you so Doylist!
Not me, Harry. Harry, being a rationalist, wants to know the truth about his world, and he wouldn't be happy with a Watsonian explanation that ignored important facts about how the world he lives in came to be.
From chapter 14
But Harry later tested time loops, and system somehow told him to stop messing with time. EDIT: If the computer MoR runs on is really able to compute infinite loops in one sweep, then there's no reason not to allow Harry to compute his primes. Instead something scarry happened so Harry had to tell himself not to mess with time. So maybe it is Turing computable after all, it just have watchdogs to stop loops after some iteration.
A simpler explanation is that "DO NOT MESS WITH TIME" was the simplest piece of information that could be generated by time travel that resulted in a stable loop because Harry's precommitment to follow the experimental protocol was weak. Also, it's impossible to prove the universe non-turing-computable.

A simpler explanation is that "DO NOT MESS WITH TIME" was the simplest piece of information that could be generated by time travel that resulted in a stable loop because Harry's precommitment to follow the experimental protocol was weak.

Simplest isn't quite as important as easiest (or most probable in terms of how reality fluid flows in a loop until it forms a stable equilibrium). The latter of course encompasses the former. In this case not only is it simple (not requiring many ontological loops) it is utterly trivial given the psychology of Harry. It only has to amplify Harry's paranoia only slightly to make him pull a reaction like that. And, in fact, given that Harry hadn't put any effort into even considering risks before doing something so extreme some reaction from him that is not the brute-forced-decryption result isn't unreasonable - so could have even happened without much consistency pressure beyond a single iteration required.

If Harry were a bit more stable and had better judgement in assessing safety he would probably have taken his time when replying and written something like "Don't be a reckless fool! Forcing black swans much?" As it happens t... (read more)

Voted up for the last paragraph
More specifically Harry told himself to stop messing with time, Harry being part of the system. Sure, if there isn't something that is more likely to happen given the state of the universe before the loop. That scary thing being Harry telling himself not to mess with time. What we infer from this depends on what we know about Harry and what sort of things are most likely to make him respond in this way. Watchdogs are a possibility. This evidence should increase the probability to this sort of thing being the case. But not by much.
Harry is stated to only have access to about half of the easier parts of the sequences. I assume the timeless physics sequence is one of the parts he doesn't have access to... From this I read that Harry's mistake is the notion that there are things that "[haven't] happened yet". http://lesswrong.com/lw/qp/timeless_physics/

(EDIT: This theory was disproven in Chap. 79)

I think Hat and Cloak is Lucius Malfoy. First piece of evidence: timing of his first appearance.

Chapter 34: Harry says "Maybe I'll just do what Draco tried with Zabini, and write a letter to Lucius Malfoy and see what he thinks about that."
Chapter 35: Hat and Cloak appears on-screen for the first time, to talk to Zabini.

Second piece of evidence: He says "Lucius Malfoy has taken notice of you, Hermione."

[This comment is no longer endorsed by its author]Reply
To quote Harry Potter: "This doesn't seem to be Lucius' style." Lucius is evil and has reason to foster distrust of Dumbledore, two points in favor of H&C being him, but his taste in plotting seems to run far more to the political style, manipulating the press, using flattery and favors to gain control, than to weird, secretive manipulation.
I agree with this. Everything or nearly everything Lucius does is technically legal and much of it is something of an open secret (e.g. everyone knows he controls the papers). That gives him the plausible deniability critical to someone who thinks as long-term as he does.
I concur that H&C is Lucius Malfoy. It seems very plain if you look at the proximate results instead assuming every character belongs in the cast of Death Note. A plan that requires that many conditionals is bound to fail. -H&C succeeds in causing a 3 way tie: The school nearly riots. -H&C gets Zabini to lie to Quirrell and Harry: Quirrell and Harry trust Dumbledore less. -H&C messes with Hermoine so that she hates Draco: Draco and Hermoine stop being friends. Not everyone has to be playing Xanatos Roulette. Some people can just use influence and get back solid and predictable returns from their actions. Lucious Malfoy makes good and predictable gains with each of these plans.
Hat and Cloak told Hermione "you are a Muggleborn and yet you possess a power of wizardry greater than any pureblood." Lucius can't believe that. He can't even afford for that belief to exist, so I don't see him uttering it, even as flattery he "knows" to be false.
Lucius knows that his enemies believe muggleborn can be powerful wizards, so he can say that flattery to look like his enemies. For people that believe blood has nothing to do with magic - they won't state the obvious.
Hat and Cloak uttered that line by way of drawing attention to the reason that blood-purists have taken her for an enemy (which is relevant because H&C wants to give the appearance of courting Hermione as an ally). As an explanation of that hatred and danger it makes sense say it no matter who H&C turns out to be.

The new Update Notifications features (http://hpmor.com/notify/) is pretty awesome but I have a feature request. Could we get some sort of privacy policy for that feature?

Like, maybe just a sentence at the bottom saying "we promise to only use your email address to send you HPMOR notifications, and we promise never to share your email address with a third party"?

It's not that I don't trust you guys (and in fact I have already signed up) but I like to check on these things.

Hat-and-Cloak is Voldemort but not Quirrell. When in Quirrell, Voldemort has a whole (probably quite powerful!) brain to run his computation on. Outside of Quirrell, he relies only on what computation he can do purely as a 'ghost', or as magic, or whatever. Hat-and-Cloak is thusly disguised because Voldemort lacks a body. Or maybe Voldemort possesses someone else, who isn't as smart as Quirrell, and is proportionally dumber and more prone to mistakes. Quirrell is zombie while Voldemort's away because Voldemort set it up that way. Don't want your robot walking away without you.

Part of the groundhog-day attack involved setting up a trigger in Hermione, that when she can attack Malfoy, she should try to kill him. This explains her behaviour in the battle, and her apparent behaviour in the duel.

Hat-and-Cloak is a player in this story. Players in this story are clever and powerful. A sensible way of resolving this apparent contradiction is to postulate some form of disability or restriction applying to Hat-and-Cloak. Then all you need is Conservation of Characters.


It would simply be bad writing to set up a mysterious and malevolent figure like Hat and Cloak and then reveal him as one of the story's established villains. It's redundant, a wasted move, to reveal that the villain was secretly a villain. It drains tension from the story to reveal that the heroes were only facing one opponent, not two. I would rule out the possibility just by assuming a competent author.

A point in favor of Hat and Cloak being Grindelwald: the playing card he chose to represent Dumbledore was the King of Hearts. ♥

Unless the reveal involved learning about the Voldemort-Quirrell symbiosis, or Voldemort-Hat-and-Cloak outsmarting Voldemort-Quirrell, or any of a dozen other dramatic reveals. At first I wanted to say "reading too deeply", but you have a point: the choice of card was not a throwaway line, it was intended to be mysterious, so it should have some depth worth plumbing.
I like it here! Everyone's so gracious. Upvoted and thank you.
You're postulating increasingly complex (ie unlikely) explanations to defend your theory. Donny's statement is strong evidence for H&C not being one of the existing villains.
That's a disjunction of several unlikely explanations; any one alone is enough to 'defend' my theory.
Why do you think that particular Santa Claus was H & C ? Sounded more like Lupin to me, with the 'getting into more trouble than James' reference.
That Santa Claus is Hat and Cloak was the implication I took from this exchange. Still seems correct to me. It's the combination of his paranoid advice and ignorance of current events. Why would Lupin tell Harry to avoid Dumbledore? (That's the letter with the 'more trouble than James' reference.)
This is a good question, and we do in fact have evidence that Lupin doesn't totally trust Dumbledore - he worries that Dumbledore may have sent Harry off to evil step-parents.
What evidence is there that H&C isn't just Quirrell wrapped in an illusion? There's no need for Hermione to have cast the lethal hex. She wins the duel, then the real perpetrator stuns both of them, hexes Draco, and then memory charms Hermione into thinking she did it. However, if that's the case, unless the perpetrator then used Hermione's wand to cast the hex, checking what spells her wand had cast would reveal something fishy. Why are we proposing the H&C is not clever and powerful?
Slips and mistakes H&C has made point to incompetence.
I'm confused about H&C. On one hand, yes, he looks incompetent. On the other hand, in Ch.35 he knew that Quirrell would be questioning Zabini about Dumbledore's plot, and instructed Zabini accordingly. How could he know that, given that Quirrell decided to question Zabini on the spur of the moment, when he heard Harry mention Dumbledore favorably? The most likely explanation seems to be that H&C is Quirrell and instructed Zabini just in case. ETA: if I ignore logic and judge only by manners, then H&C seems to be Snape. But why?
If Voldemort's possession ability worked like that, though, why wouldn't he just use Quirrel's body for that? You'd think that he would make sure to use his smartest host for anything requiring puzzle solving or careful manipulation.
Perhaps Voldemort doesn't want Quirrell to know certain going plans? Perhaps Voldemort thinks not involving Quirrell is the most effective method of convincing targets that someone other than Quirrell is doing this? Perhaps Hat-and-Cloak's secrecy is to normal people what Quirrell's brilliance is to Harry (convincing), and Voldemort thinks or know that Quirrell can't pull off being H-&-C properly? Perhaps Quirrell is monitored in some way that he can't safely or nonsuspiciously avoid (I can believe Dumbledore setting up some such thing) and so Voldemort does just enough to fly under the "openly hostile" rader, using Hat-and-Cloak to strike the tinder as it were? I don't know, but I suspect that if my claim is the case, the answer to your question is a reason the story itself does not reveal. He certainly does the lion's share. Perhaps Hat-and-Cloak only handles less challenging or less dangerous-to-fail situations.
I was under the impression that Quirrellmort's zombie-time meant that the Quirrell host-body had been lobotomized. If so, any intelligence that Voldemort can bring to bear is already native to him. Of course, there is that comment in one of his early discussions with Harry about never being able to fully disentangle the mind from the body that it wears...I'm not yet entirely sure what to think about this. I don't think we have any direct evidence that Voldemort can step out of Quirrell without great inconvenience.
When H&C drops the disguise, Hermoine recognizes him/her. I don't think it is particularly likely that ghost-Voldemort looks anything like any picture of him from a history book. So how would Hermoine recognize him?
I feel that I should point out that when the black mist lifts and Hermione recognizes the face of her assailant we have no reason to believe that the face she recognizes is not itself an illusion. Since we already know that she has been obsessing about Draco, I suspect that it may even have been his face (though with the information we readers have it is obvious that H&C is not actually he), though I don't put a great weight on that suspicion.

If Harry does not manage to find the real culprit, then how does he save Hermione from having her wand broken?

Breakout/Direct Attack on the Wizengamot / Malfoy Manor

  • Transfigure a one-atom line of antimatter through the earth's crust all the way to the Wizengamot or Malfoy Manor, and then a small bubble there. His wand is then touching the item to be transformed, and it will work.

  • Go to Azkaban and round up a few hundred dementors.


  • Transferring the cloak of invisibility to her somehow.

Bringing Hermione under the aegis of a noble house

  • Adoption or marriage

Transfigure a one-atom line of antimatter through the earth's crust all the way to the Wizengamot or Malfoy Manor, and then a small bubble there. His wand is then touching the item to be transformed, and it will work.

Ten points to Slytherin for creativity. Minus ten bajillion points for holy shit, are you suicidal?!

That's just 15 joules per cubic meter of rock, until you get to the bomb. Not even detectable. I wonder, however, how the magic source is going to do turning energy back into matter afterwards.
Damn. Why are people not blowing things up with antimatter all the time?
Ignorance, high transfiguration skill level required, magical safeguards in place, possibly.
Makes sense. We could probably also build a power plant powered by transfigured antimatter.
Why would the magic source do that? Wouldn't the antimatter just react with the surrounding matter and turn into energy under the laws of physics, and stay that way? How did you get 15J, by the way?
Cube root(number of atoms in a 1m^3 cube of silicon(simplification)=number of atoms in a one atom line, assuming that the atoms were arranged in an cubic crystal(simplification). Mass-energy of those atoms, times two (for complete destruction) and then subtract for the particles that do not decay immediately (I had to look that up, I think I got about 5/6th remaining)
How would blowing up Malfoy Manor help Harry anyway? He'd be hurting Draco, who loves his father, and the court case brought by Draco against Hermione would go forward.
Are we sure of that? The trial might vanish if the House of Malfoy is extirpated.
I'm sure Harry wouldn't want to extirpate the whole House, which includes Draco. Just killing Lord Malfoy (and any servants who happened to be near) is enough collateral damage that Harry wouldn't seriously consider it if Hermione isn't facing outright death herself. Besides, I'm pretty sure there are other branches of the Malfoys that would inherit the title. Draco mentioned an uncle or some other relative not in the line of succession who used to visit him at least a few years ago.
Even better- That uncle will likely want the title, so Harry just needs to bargain with him. "If you get the title, you'll drop all charges, right?"
Won't save Slytherin, which is one of HP's goals.
I'm guessing that currently Hermione factors about 50 times more in Harry's utility function than the whole of Slytherin House put together.
Hermione is much more important, but HP would prefer a plan that did not inherently make Draco his enemy. I don't think it is much of a stretch to think exposing Malfoy Manor to anti-matter would make Draco become an enemy.
Only because she's in more and more immediate danger. It might be possible to build another plot to help Slytherin later, but Hermione needs help now.
Bribery, Trade, or Begging Harry could offer to pay Lucius Malfoy something in restitution. It couldn't just be money or an incredible favor. As the original 'Taboo Tradeoffs' paper mentions, people only get more angry when you try to do that. Harry would need an accurate model of Lucius suspecting him as Harrymort and be able to trade him something that Harrymort would consider sacred. * Trade his invisibility cloak to Lucius for Hermione's freedom. Make sure to play up that it is 1/3rd of the Deathly Hallows and thus something Harrymort considers sacred/invaluable. * Trade Lucius a blood debt from the House of Potter. * Make an unbreakable vow to protect Draco or otherwise help Lucius (or some other ritual). * (Assuming Roger Bacon's diary is indeed the diary Horcrux and Harry manages to discover that) Trade Lucius a piece of Voldemort's soul as apology. None of the trades seem particularly smart or likely, but Harry might consider a few of them if he got really desperate. They seem to be of sufficient value to Lucius (or rather, to Harry's model of Lucius' model of Harrymort) to prove that Harry is genuinely sorry and be worth Hermione's life/magic/future.
4Joshua Hobbes
He consults professor Quirrell, accuses him of setting this all up to rob him of friends, and demands that he free Hermione in order to prove his innocence and good-will. Quirrell disappears, reappears, and informs Harry that Lucius had a change of heart and is dropping all charges.
Stealth - not only he must transfer cloak to Hermione - he must also get Hermione out of court, and she must be in cloak at all times to prevent tracking magic, and Harry must have the cloak with himself, when Dumbledore will want to see it, when tracking magic will stop working (and there's spell that detects if cloak is nearby). One way to do this - duplicate cloak using time turner for the moment Dumbledore will want to check it. Scheme: * Harry takes cloak, mokesking pouch, and time turner with himself to the court * Harry waits for Hermione to disappear * Harry puts his mokeskin poach under the table or somewhere and not look at it * Hermione disappears * Dumbledore try to track Hermione and fails - so he checks if cloak is near - it is, so he asks Harry about it - Harry shows cloak to Dumbledore and it's empty * Harry goes back wearing cloak just before the moment Hemrione should disappear, takes the mokeskin poach that he left under the table, somehow makes everybody look elsewhere and put Hermione into his own mokeskin poach which he keeps under the duplicated cloak (may need to use potion or sth that will turn Hermione into animal or thing or sth that he can put into poach - like with Quirrell as a snake). * Harry in the past waits for Dumbledore to check the cloak that Harry in the present has with himself, waits for everybody to get out, and somehow passes the poach back to himself without looking at himself. Harry in the present puts poach into the cloak. Possible failures - Dumbledore can keep the cloak, making it impossible to hide Hermione after the time turner is used up. I think Dumbledore won't do this - he didn't wanted to keep cloak to himself, he wants Harry to have cloak just in case, and even if he see throught this plot, he can let it slip, because he probably don't want Hermione to have wand snapped. But it's one failure mode. Also Harry must be prepared to "prove" he didn't used up his TimeTurner, like he did after Azkaban
How would Harry even get to the trial in the first place? Dumbledore won't let him leave Hogwarts, and if he did, why should the Wizengamot admit him to the proceedings unless e.g. Dumbledore requested it? And why would D. do that unless he expected Harry to succeed in helping Hermione escape? But if D. wanted Hermione to escape illegally (possible but unlikely IMO), he could surely arrange that himself without Harry's help and presence. (Maybe he'd borrow the cloak...)
"Harry had used up all six hours from his Time-Turner, and there were still no clues, and he had to go to sleep now if he wanted to be functional at Hermione's trial the next day." I assumed this means Harry will be at trial. Probably as a witness?
He could only be a character witness, at most. Not very relevant to the trial at hand. Maybe Dumbledore will just bring him in as a spectator, and wouldn't have to ask anyone's permission. We don't know what the rules for that are.
He is a member of a noble house. He is probably entitled to observe, even if his age prevents him from taking his seat.
Items aren't held in stasis while in mid-transfiguration as far as I am aware. I'm not sure he even needs a line anyway.
Ok, do the same with a radioactive substance- it won't do anything until enough has been transfigured to go critical.
It took me a while to figure out what you meant by this. I'm pretty sure, from the descriptions we've been given, that while transfiguration requires some time spent concentrating, the actual change happens instantaneously at the end- if you're interrupted before you finish, nothing happens.
As an airborne scout, Goyle was able to report what HJPEV & Blaise were in the process of transfiguring during the battle in chapter 78. Is that less than conclusive evidence that the transformation is gradual?
You know, you're right. I was going off the demonstration of partial Transfiguration: Which seemed to me to indicate that the glass didn't appear until a few minutes after he started the transfiguration. And the bit where Harry cuts through Azkaban's interior wall seems to make somewhat less sense if it's gradual- the motor oil would just drip out, for instance. But the fact that Goyle could recognize the cauldrons before the transfiguration was done pretty conclusively rules the idea out. Oops.
The transfiguration idea is very clever, but I suspect that the Wizengamot and Malfoy Manor would both have powerful defenses which would block harmful transfigurations. It also isn't clear what the range is on transfiguration.
Harry would never use dementors as his army. Problem one, Dumbledore is Harry's legal guardian and would need to approve such acts. Problem two, there is then a blood debt from House Potter to House Malfoy, so maybe Harry has his wand snapped instead of Hermione, and how is that any better?
I'm assuming that the evidentiary standards are higher for conflicts between noble houses. I could also imagine a trial by combat alternative.

As much as I'd love it, there's no chance of a trial by combat. "If we did it your way, Kingslayer, you'd win. We're not doing it your way."

I'm getting the sense there isn't an evidentiary standard at all, not in any case. Each side argues their case and presents whatever evidence they like, and then the Wizengamot votes whatever the hell they feel like, nonwithstanding evidence to the contrary. Remember what Draco told Potter back at the train station: the Malfoys can get out of any accusations before the Wizengamot, like a non-noble accusing Draco of rape, simply because they've got the votes. Or the case with clearing Hagrid of blame: Quirrel said it would go ahead "because Lucius would have no reason to oppose it" (my words).
What, Lord (Harry) Potter against Lord Lucius Malfoy? What a fine trial by combat that would be.
0Joshua Hobbes
No, they'd be allowed champions, and Dumbledore would win.
If it were that easy, Lucius couldn't contest Dumbledore politically. I suppose the Wizengamot would have to rule to adjudicate by combat, and they won't in an apparently clearcut murder attempt case.
Well, for underage wizards, they get a champion, obviously. Dumbledore or Quirrel, I'd assume.
Before the Heaven's Feel arc, you mean.
Can somebody dereference "Heaven's Feel arc" for those of us who aren't familiar with it?
Fate/Stay Night comes up in MoR as the franchise whose Fuyuki City trips up Quirrel in the interrogation*; the 'Heaven's Feel' route is one possible plot in the FSN franchise. Plot summary, ref is probably to evil-Sakura's 'army of shadows', which matches up well with Dementors. * I looked it up, and Quirrel's visit there in 1983 or whatever would have coincided with the birth of a few minor characters but nothing else important in the FSN universe, as far as I could tell.

Eliezer suggests re-reading 14, 21, 26, 35, 43-47, 56-57, 63, 66, 73-77, chapters

What're the possible clues embedded in these chapters?

  • 14 - Time-turner given to HP, Santa Claus gives inv Cloak
  • 21 - Hermione worried that she was going 'bad' + Bayesian Conspiracy starts + Draco wants to learn about blood + SC gifts 2 galleons, Occlumency book, advice about Quirrell, and warnings about Dumbledore
  • 26 - Noticing Confusion. A Muggle casts a dangerous spell on a Slytherin without knowing what the spell would do, also the Weasley's plot in the Prophet. Bacon's book to HP, Killing of Rita Skeeter
  • 35 - After HP/Q talk at the end of the battle. Also, Blaise Zabini + H&C interaction, Harry teasing Draco about Draco/Hermione working together.
  • 43-47 - Killing of the dementor, ends with HP & Draco discussion, Harry taking an oath against Narcissa's murderer, Harry shown to be a Parselmouth
  • 56-57 - Couple of chapters in Azkaban
  • 63 - TSPE Aftermath, Harry recognizes Hermione as 'good', Trelawney's aborted prophecy, HP receives SC gift of pack of cards.
  • 66 - SA Part I, key seems to be "Lessson I learned is not to try plotss that would make girl-child friend think I am evil or boy-chil
... (read more)
The first thing I noticed is that the list contains the Santa Claus messages and H&C appearances (14, 21, 35, 63, 77). Presumably all chapters that contain strong and deliberate hints at H&C's identity are on the list. I notice that neither the chapter where Remus talks about Sirius and Peter, nor the chapter where a prisoner is mumbling "I'm not serious [Sirius]" are on the list, so H&C is unlikely to be Sirius. On the other hand 65 which has Quirrel explain that the port key Santa Claus sent had a misleading description attached is not on the list either, so that may not be definite.
In 14 - Harry's Invisibility Cloak is not given by Santa Claus - the letter is unsigned unlike future letters - and is almost surely given by Dumbledore himself. Perhaps this is a hint toward the use of a time-turner? (Does Hermione know about Harry's time-turner yet? ) 63 is on the list - where Harry actually receives the gift from Claus. Also, 43-47 has Harry going deep into his dark side, that's probably more the clue than killing of the dementor. OT - Whoa! I didn't realize that http://hpmor.com/chapter/58 had someone saying "I'm not serious" - awesome!
The reason the later letters are signed "Santa Claus" is to signify that they are from the same anonymous person who was wishing Harry a merry Christmas and giving him an early Christmas present with the first note. Otherwise there would have been no reason to use the alias Santa Claus. It's possible that they are from another person merely pretending to be that anonymous gift giver, but then it's also possible for any appearance of a non-POV character to be someone else under the influence of polyjuice. if you were going to make an objection of that kind it would have made a lot more sense to object to calling Hermione's assailant H&C.
Aah, somehow I read your earlier statement to mean H&C & Santa Claus were the same. And you're absolutely right, Santa Claus is one person, and the name signifies it is the same person. Looks like Harry told Quirrell that it was signed Santa Claus - we should assume in the future letters are from the same person or Q, since Q would definitely forge such letters if it was to his advantage. My hypothesis for now is SC = Dumbledore/Nicholas Flamel. H&C = Quirrell. And 75th above makes a strong case for SC=D - http://lesswrong.com/lw/ams/harry_potter_and_the_methods_of_rationality/60uj

It seems that the popular opinion around here is that Mr. Hat & Cloak is someone, anyone, other than Quirrellmort. I think this is a case of the same kind of thinking that led people to wonder whether Quirrell was Voldemort a lot longer than Eliezer intended.

I think Eliezer probably meant us to know that Quirrell was H&C the very first time he appeared. Quirrell follows after Zabini when he leaves Harry; Zabini says that Quirrell reacted exactly as H&C told him he would. He knew how Quirrell would react because he is Quirrell, and he told Zabini to do what he did specifically so Harry, who Quirrell knew would be around after the ceremony, could hear it and have another reason to distrust Dumbledore.

Eliezer has already dealt with this once. Everyone suppressed their own knowledge of canon and faculties of logic even in the face of nigh-incontrovertible evidence that Quirrell was Voldemort. He expressed his confusion at this in the author's notes, and I believe he vowed to make his blatant hints more blatant in the future.

I think Quirrell being H&C is even more blatant than Quirrellmort was, and here we are doing the exact same thing. We do it because we love the stor... (read more)


Ha! Or maybe Eliezer has been rolling his eyes at us (or, rather, y'all), and gave us a blatant hint with the contrast of competent Quirrell interrogating sneaky Snape and less experienced H&C working on naive Hermione. I think you're just clinging to your one beautiful idea, instead of examining other possibilities - like, say, H&C is taking instructions from Quirrell, maybe?

See? Two can play that game.

I disagree with this at least as strongly as you believe it. I'm pretty sure he meant Hat and Cloak to be a giant question mark. Hence the elaborate descriptions of the broad hat, the dark mist, and the gender-concealing cloak, all drawing your attention to the mystery of his identity. There have been hints, but they don't all point in the same direction the way they do for Quirrell and Voldemort. Some are red herrings. I conclude that we're not meant to be certain of who he is. We're meant to wonder and doubt.
I'm not sure why almost everyone assumes that the first and the second H&C is the same person. Is there any reason to think so, beside their appearance? Same appearance is a clue to the two H&C-s being related, but not necessarily to identity. For example, a hat and a cloak may be a uniform in a secret society, to be worn in special circumstances. Or, maybe two of them were friends and did pranks like that in their youth. Or, one of them saw the other do this trick once long ago, was impressed, and remembered it. Etc etc. What I'm leading to is the possibility of the first H&C being Quirrell, and the second being Lucius.
I much like the idea of this being a standard spell, as that provides further cover for your identity. They Guy Fawkes mask is the modern equivalent.
I think Eliezer referred to both of them as "Mr. Hat-and-Cloak" in the author's notes.
The problem I have with this is that it's unnecessary from Quirrel's point of view. If Quirrell wanted a 3 way tie, he could have managed that himself as the organizer. If Quirrell wanted Blaise to testify about Dumbledore, he could have pulled the same trick Kingsley did in book 5 at far less risk. If Quirrell wanted to convince Hermoine of something, he wouldn't have needed multiple tries reset with Obliviate. Quirrell being H&C is superfluous frow Quirrell's point of view. He could have achieved all of those by himself.
You realize Dumbledore was the one who made the 3-way tie happen? Zabini was just reporting on it to quirrel and HnC. Quirrel might want blaise to talk about dumbledore IN FRONT of quirrel and not give away that quirrel ordered him to a cunning observer, such as harry. This would mean giving him orders as someone other than quirrel. As far as hermione goes, do you seriously think any idea she gained from quirrel would be as convincing to her as one conveyed by whatever entity he ends up using in the memory attack? As she said, she doesn't trust HnC when he appears extremely suspicious, and she would never trust quirrel for the exact same reasons.
Ah yes, Dumbledore did indeed wish for the 3-way tie to happen. Although it did occur with the full consent and knowledge of H&C. Whoever H&C was, he let that plan go through. I will point out that Zabini didn't just report it to Quirrell/Harry, but rather reported a distorted version that involved giving false information. The trick I'm referring to in book 5 is when Cho's friend is testifying to Umbridge and Kingsley changes her testimony right before she gives it. It's been a while since I read it but it was probably the Imperius or Confundus. Eg, if Quirrell were willing to go these lengths to mislead Harry, he could have just cast a spell on Zabini and be done with it. Also, I agree with you about Hermoine not trusting anything she heard from Quirrell. However, I only said that Quirrell wouldn't need so many tries, not that he'd talk to her with his face. He's had her as a student; he's interacted with her personally; hell, he's made her a general and has her marked as a person of interest. He would already know what it takes to convince her. He would have succeeded with a singly try instead of wasting hours in that corridor. What's more, Quirrell is a master legilimens; if he's willing to pull off a Groundhog Day attack on her he might as well just read her mind and get it right the first try. There's no point in wasting time, magic, and risk of getting caught when you could just do the job perfectly in 30 seconds.
I think you're overestimating Quirrel. Harry finds him extremely persuasive because he's inclined to agree with him, because he's grown to trust and like him. Hermione might respect him as teacher, but she doesn't trust OR like him, and this is obvious whenever harry tries to tell her something Quirrel told him. EVEN when you're extremely competent some things simply take some trial and error to get correct, and understanding a mind that's diametrically opposed to yours should be one of those things. Quirrel doesn't know EVERYTHING. As far as legilimency goes, it's established that that the person needs to be thinking about a topic or atleast about similar topics before you can find out about it. This means that legilimizing someone in order to gain their inner motivations, worries, and handles is definitely gonna take way longer than 30 seconds.
- - In chapter 75 Snape gives Hermione a rather thorough dressing-down in front of the school. Did the Groundhog Day attack in chapter 77 happen on the same day? I have been assuming that Snape & Harry were broadly correct, and the Groundhog Day attack was how that madness-guiding trick was done. My working-theory is that the entire purpose of the attack was to produce a directed trauma, and an obsession, without a readily detectable cause. Xachariah and Drethelin, if I've read you right you both believe that Hat and Cloak's purpose was to put some idea or belief into Hermione's head; to convince her of something. I think that there is something rather deeper and more subtly manipulative going on here. [Edited for formatting.]
Having one's mind read for the first time seems to leave some kind of trace; if he's not sure she's ever had her mind read before he shouldn't try it because then Dumbledore or Snape could learn later that someone's been peeking.
This seems to be borne out by the events of Chapter 79: Even if Hat and Cloak is Quirrell, the job had to be done the hard way, without Legilimency.
What really throws this for me is that Quirrell is said to go down the hallway in the same direction as Zabini, and then in the next section Zabini meets H&C. That is so blatant that I actually consider it an anti-clue. It's like someone pretending to steal something and whistling nonchalantly to draw attention to their jest-theft. Contrast to Quirrell trying to permanently Dement Harry during the Humanism arc, which was subtle enough that I completely missed it in the first reading (tho didn't hurt that I was very biased by my adoration of Quirrell at that point).
Wait, what? Has this been discussed somewhere?

Somewhere in the old threads I think, but I'm in a rush and can't look it up right now. Quick points:

  • Quirrell organized the whole Dementor visit from the beginning
  • Quirrell waited until Hermione was running up to the Dementor and would've seen it herself anyway to "suddenly notice" Harry's wand next to the Dementor's cage
  • Quirrell suggested the Headmaster leave early, before it was Harry's turn
  • Quirrell instructed Harry's friends to "give him space" even though he probably knew that it was better for Harry to be surrounded by his friends as Dumbledore said
  • Quirrell undermines Harry's confidence just before he goes in front of the Dementor (If you can't do it, I at least will understand)

All plausibly deniable, and exactly Quirrell's style.

That implies he at least suspects Harry holds a horcrux...
Holy crap.
Why would he want to kill Harry? And if he wanted to, wouldn't he have done it by now?
Demented Harry is Evil Harry, not dead.
What? The people in Azkaban were close to dead, not cunning evil geniuses. Dementors weaken you and suck the life out of you.
Chapter 44 is the goal-state

Am I the only one that's worried about Trelawney's prophecy? My vague recollection is that she's a joke of a diviner, but when you get right down to it, the fact that she predicted the same thing for each student in the class isn't such a huge likelihood burden if you consider that they are not necessarily independent events. That is to say, she may well be predicting the death of someone all the students know. Which would suggest a tragic ending to this story, probably, unless it's someone all the students Know-Who.


Or she's predicting a very imminent war.

  1. HPJEV has told Quirrel that Lucius threatened him with dire consequences if anything happened to Draco.
  2. Q can't make HPJEV do anything directly
  3. Q, in the form of H&C, makes Hermione hurt Draco,
  4. Why? One or more of ...
    • To get Lucius to hurt Hermione
    • To get HPJEV to his dark side, moving him away from Hermione
    • To show HPJEV that no one is really 'good', ie even Hermione can hurt someone else

If that's not true, then all I can say is "I am confused".

2Joshua Hobbes
I quite doubt Lucius is upset with Harry at the moment. He's not stupid, and Harry is not to blame for what happened to his son. And I'm quite confident Quirrell is not H&C, as the Defense Professor would have been considerably better at brain-washing Hermione. Besides, Harry will know that Hermione truly going dark is far more unlikely than interference via mind-magic or blackmail. He is going to stay on her side and investigate what happened, and Quirrell would anticipate this and not expect Harry to fall into darkness.
Harry's not to blame, but the person Lucius believes is posing as Harry might well be. From Lucius's perspective it must seem more likely that Hermione is a cat's paw than that she's actually strong enough to beat Draco fairly. Plus, having a Muggleborn arrested for the attempted murder of another student hurts Dumbledore as well. It would be far from unreasonable for Lucius to leap to conclusions at this point.
He would not have been considerably better at brain-washing Hermione. Others, yes, but not Hermione. Quirrell is Voldemort, the ultimate evil (that we know of). Dumbledore has said that "Evil is that which does not love, and cannot know love without ceasing to be evil," or similar. Quirrell has already tried to convince Harry that Hermione is making a show of goodness to further her own ends. If he really believes that to some extent, given that he's the ultimate evil, he would have a hard time modeling Hermione's thought process well enough to get it right on the first try.
8Joshua Hobbes
Eliezer thoroughly deconstructed Dumbledore's (And Gandalf's) view of evil in Lord of the Rationality. "If the Enemy thought that all his foes were moved by desire for power alone - he would guess wrongly, over and over, and the Maker of this Ring would see that, he would know that somewhere he had made a mistake!" Even if somehow Quirrell was stupid enough to not truly understand non-sociopathic motives, he would not make the obvious mistake of revealing this weakness to Harry. Harry thinks that Quirrell can't comprehend good because that's what Quirrell wants him to think. And H&C didn't even fail because of a miscalculation about Hermione's altruism. It was a rookie mistake to not use a different appearance than you did with Zabini. Even if you still wanted to look dark and mysterious, you wouldn't pick the exact same disguise you used earlier, just in case. Finally, H&C's dialogue is highly unquirrellish. "I hoped for better from you, Hermione. Surely such a Ravenclaw as you, the most intelligent Ravenclaw to grace Hogwarts in a generation, knows that appearances can be misleading." Those are not the words of a Dark Lord who doesn't care about your opinion and is about to wipe your memory.
They are precisely the words of a mysterious person who's trying to persuade you of something. It's simple flattery. Excellent point, but I hardly think this is a Sauron-level mistake. He may not absolutely fail to consider the actions and thoughts of moral people, but that doesn't mean it doesn't take him a few tries to find what buttons to push on an almost absolutely moral little girl. Quirrell has to have some weakness, after all, if Harry is to ever beat him, as he presumably will. Why couldn't it be that Quirrell is truly cynical and does truly believe all people act selfishly most of the time? Why couldn't that omake be a foreshadowing of Quirrell's downfall? Quirrell would never have left Mount Doom unguarded, but that doesn't mean he won't make some other, smaller critical mistake. He might have revealed a weakness to Harry, even as brilliant as he is. He certainly doesn't love Harry, he's certainly not fond of him, but I think he feels a kinship with him, given that Harry houses a piece of Voldemort's mind/soul/whatever. In his effort to turn Harry Dark, he might yet reveal more than he should. Quirrell doesn't have to be perfect. If he were, then Harry could never defeat him. Just that he never holds the Idiot Ball doesn't mean he doesn't make small, insignificant-seeming mistakes that may haunt him later.
I have no strong opinion on whether H&C = Quirrell, but Harry has already remarked on Quirrell's facility at playing different roles.

The strongest evidence that H&C is not Quirrell seems to me to be how much more amateurish he is at manipulating people than Quirrell is. I don't believe it would have taken Quirrell dozens of iterations to realize he ought to change his appearance. It probably wouldn't have taken him one.

As you should know, appearances can be misleading. (This was not the first iteration, so whatever the default, this iteration already incorporates some adjustments.)
Yes, but he wouldn't have made obvious slip-ups. H&C came within two words of blurting out "Time travel." No way Quirrel did that, unless he's playing a nth-level game through the fourth wall. (Which I wouldn't put past him at this point, but anyway...)

So, possible Wild Guess, but has enough reinforcement that I'm going to throw it out there.

Right now, it seems like Eliezer is pushing to the trial. The chapter implies that Harry has done nothing else of note before Hermione's trial, meaning he will have limited ability to defend her. Without any sort of evidence to raise reasonable doubt, he'd basically have to manipulate the Wizengamot.

... Which, while beyond Harry's ability, is not beyond others. In particular: Quirrellmort.

If Quirrell manages to get Hermione acquitted...

1) Quirrell earns lots of Harry points. Regains trust after the Azkaban semi-fiasco.

2) Quirrell emphasizes his role as Harry's mentor and protector when even Dumbledore is helpless.

3) Meanwhile, this whole fiasco has convinced Harry even more that the wizarding society has issues.

4) Hermione is reinstated as an ally of Harry. If Quirrellmort's goal is to strengthen Harry, this is also a plus.

5) Draco is now a victim of a plan, and earns pity, not respect, destabilizing Lucius' power base.

If, simultaneously, Quirrell were to keep Lucius from undoing Harry's turning...

1) Again, adds another ally, Harry points, etc.

And if both... then we have two heroes of Slytherin and of Ravenclaw who survived an evil plot, and may well garner sympathy for that plot. And remember, Quirrell promised to make Slytherin and Ravenclaw simultaneously win the House Cup...

3Joshua Hobbes
Quirrell storming into the trial when the majority of the audience believes him to be the one behind everything sounds quite like this story's style. The trouble with this theory is that the arc is confirmed to last until chapter 84, and Quirrell being suddenly released from custody would be far too short of a resolution. I suspect Harry and Co will come up with some sort of last-ditch effort during the trial, leading to some sort of awesome event like the previously suggested Trial-By-Combat (though obviously not that). I suspect Quirrell will play some part in the end, though. Oh, and I'd like to predict that we find out H&C's identity during this arc.
It was mentioned that Fawkes was in the room. Maybe Harry threatens the chamber with having Fawkes teleport him to Azkaban and destroying all the dementors after demonstrating on the one in the room.
It is surprising that Quirrell would accidentally reveal himself as an impostor during interrogation; so, perhaps the Quirrell currently in custody is an impostor--meaning that he is not the Quirrell currently teaching at Hogwarts. If so, the imposter is there to give Quirrell time to do something else. He may be attempting to prove Hermione's innocence (even if he is to blame for the current situation), or he may also be after the Philosopher's stone.
Highly unlikely unless there are two Quirrels running around in possession of powerful wandless magic (remember the 'sneeze'?)
The "ending at 84" is actually another reason I thought this was likely, because frankly, there's only so much Harry can do at the trial itself. I'm imagining the next four chapters or so being about the aftermath of the trial, seeing Hermione's and Draco's reactions and the ripple effects of the trial.

Chapter 25, Fred and George talking about the Marauder's Map, which is supposed to show all people in Hogwarts by name:

“Still on the fritz,” said George.
“Both, or—”
“Intermittent one fixed itself again. Other one’s same as ever.”

The intermittent one is probably Quirrell, going in and out of zombie mode. But what could be visibly wrong with the other one? My theory is that, unlike all the other dots on the Marauder's Map, one of them doesn't have a name. Who could that be?

I hypothesize that this is Mr. Hat and Cloak. That would mean it's not Quirrell and not anyone the Weasleys would pay much attention to, either. The map must get the names it displays from somewhere, and its reliability in doing so suggests that it gets them from people's minds. My hypothesis is that to appear on the map without a name, you'd have to (a) not be known by name and present appearance to anyone whose mind the map can read, and (b) be an occlumens.

Intermittent one is either people using time-turners, Weasley's don;t know about time-turners, so they think it's showing one person in two places or If it showed two names for the same person, that might be an intermittent bug too, ie Quirrel/Riddle based on who he is at the moment. Permanent bug might be someone floating in the castle who they know shouldn't be there, perhaps Pettigrew, or Sirius, or someone who should be there but isn't - ie Quirrell being unplottable. Dumbledore & Snape are known Occlumens, but they show up on the map just fine. In canon, the bug that Harry saw was Pettigrew on the map but he wasn't actually there in reality.
I don't think either of the glitches are Time-Turners. Time-Turners have (presumably) been used regularly in Hogwarts since the twins arrived, and it's made clear that these glitches are new:
Also, bear in mind that the official story is that the time turners are used to treat "spontaneous duplication"; if the map occasionally registers multiple versions of a "spontaneous duplication" sufferer, that would be written off as a feature, not a bug (just not the feature that the twins think it is).
1Joshua Hobbes
I think it's likely that Harry is one of those errors. We he goes dark-side his name might change.
I don't think George would describe a glitch where someone's name changes as being "same as ever".
3Joshua Hobbes
I mean that he might be the intermittent one instead of Quirrell. If maps like these really do show one's true name, as with Scabbers and Crouch in Canon, then Quirrell probably knows about them and made himself generally unplottable, not just intermittently.
My guess is, the intermittent one is H&C taking the appearance (and name, on the map) of students who are elsewhere to walk among the children, listening to rumours, maybe even talking to them. I'm going to assume he can disappear as well as change shape when out of sight, otherwise it would be too easy to track him down; plus, that's why it's 'intermittent'.
The last chapter to me indicates strongly that the glitch is Voldemort's spirit. Now you might ask, 'wouldn't George & Fred be scared witless by Voldemort appearing on their map occasionally and maybe even report it?' But Voldemort is a pseudonym and the spirit would show up as 'Tom Riddle', as Dumbledore's PoV indicates (notice Dumbledore has no problem saying 'Voldemort' in other contexts, but when he uses the Map, he asks for 'Tom Riddle'). Canon indicates that Voldemort's origin is a secret: Dumbledore spends years digging out the link and the diary in Chamber of Secrets seems to think it's telling Harry something good when it explains the anagram 'Tom Marvolo Riddle' = 'I am Lord Voldemort' or whatever. So the twins wouldn't make the link. What probably happened is they noticed the glitch - maybe it claimed Riddle was in the same room as them at some point? - and investigated carefully, not finding anyone where the Map said a Riddle was. Perhaps they did some more digging and turned up Riddle's old school history as Head Boy etc. Naturally, they conclude the Map is buggy: 'old students from half a century ago are showing up! Bugs in the Map are not good!'
Perhaps the twins were very careful with the Map, as would be appropriate for illicit tools of mischief, and never used it while they were in the same room as anyone else. It would be dangerous to do so, and their mischievous uses for it could easily work around such a restriction. That, greater concerns, and a little bit of narrative/circumstance, could keep them from ever laying eyes on the people that corresponded to their glitches.
Well, yes, so imagine their shock when after the usual precautions they solemnly swear and see a third person listed in the room with them.
The Disillusionment Charm is commonly known, yes? That wouldn't be mysterious, I don't think. It would be shocking and frightening and frankly it ought to have happened at some point and the twins ought to have lost their Map because of it. Or maybe they take precautions that would protect them against all the hiding tricks they know about and, you're right, still encountered an extra name now and then. Still, I have a bit set that suggests the narrative would be more specific about that case, though I can't justify it.

Everyone seems to be holding the idiot ball with regards sending Snape to check Hermoine's room - this makes me suspect Dumbledore was behind the escalation.

Dumbledore just can know about Snape's schemes, and also want him to believe, that he doesn't know. If he consider Snape's game mostly harmless...

Is Harry's guess at the twins' prank on Rita the correct one, and by corollary, are we supposed to believe that Quirrelmort couldn't come up with a hypothesis that basic, and/or that it had been that easy for the twins to successfully brainwash an adult witch? (And on a meta level: was it worth it to make such a hubbub with such a supremely, well, boring answer?)

The twins didn't brainwash Rita, they paid somebody to do it for them.

Harry leaps to that conclusion before hearing from Dumbledore how difficult they are to create. Even if that was the method, there is still the question of how they managed to accomplish it. My hypothesis — as of several chapters ago — is that Dumbledore assisted in the Rita prank. He certainly had the motive, since he's playing the game against Lucius and Rita was Lucius's pawn. He also had the means (being incredibly powerful). Why hadn't he acted against her earlier? Because he hadn't been clever enough to think up a good way to get at her without inviting retaliation. So how did he ever get included in the twins' plan? Easy: he's in the habit of routinely reading their mind. Evidence for this lies in chapter 63: "It wasn't that the Headmaster had popped up out of nowhere and was staring at them with a stern expression. Dumbledore was always doing that." There's also weak evidence in chapter 12, where Dumbledore knows Harry wants to reformulate Quidditch (he could know via F&G via Ron). And in chapter 79, where he knows about the map. So: The twins are walking around thinking about how to implement their plan against Rita, Dumbledore pops up out of nowhere looking for some good gossip, sees their plans, seizes the opportunity. The exact implementation could either be a memory charm (maybe trap her when she shows up at Mary's room looking for gossip about Amelia Bones, Dumbledore's ally), or else Dumbledore could actually pull off the acts Quirrell calls impossible.
Hold on - didn't Lawful Good Dumbledore make a big deal earlier in the Snape fight that he didn't invade student's minds?
He promised that Snape would not read student's minds.
Also, they aren't students. They're Fred and George.
Yes. That was the point of the whole incident.

An important hint: "Obliviation cannot be detected by any known means, but only a Professor could have cast that spell upon a student without alarm from the Hogwarts wards."

This means no Lucius, no Sirius, no Lupin, etc.

0Joshua Hobbes
Very Interesting. Are we certain he doesn't just mean that Hogwarts only detects student's spells? Probably not. Do you think individuals who were professors in the past but are no longer might not be detected?
If only Zabini had spoken more with his older cousin, he might have remembered that five years ago, Defense was taught by Professor Hat-and-Cloak. More seriously, if Dumbledore thought to make sure no one could bring the same Dementor back the next day, he probably wouldn't neglect to revoke, say, Slughorn's permissions.

Presuming this all does lead up to a trial, I look forward to Harry's reaction to the Magical Justice System.

"Hasn't it ever occurred to anyone to have a suspect's guilt decided by an unbiased panel of judges?!"

7Joshua Hobbes
Oh, and I suspect that the Sorting Hat Summoning is going to happen during the trial, perhaps as a means of impartial mind-reading.

Oh, and I suspect that the Sorting Hat Summoning is going to happen during the trial

Yes, it is.

Either that or Eliezer anticipated this train of thought (not unlikely) and is playing at the second level (slightly unlikely). Multiplying that out, the probability is miniscule.

Eh, by now you know you overthought this. Eliezer could have just meant that he knew there was a trial coming up, or that the song in question mentions the word "hat", or a number of other possibilities. Seriously, don't limit the hypothesis space to "Either my current theory is exactly right to the letter" or "Eliezer tricked me into thinking the current theory is exactly right to the letter". It's always possible that the other guy just meant something different, no deception involved.
Lesson learned: (However, if the Sorting Hat is summoned again, during the trial, this time with Pervenit Judex, I shall be very, very, tempted to conclude that Eliezer is just trolling us.)
Eleizer is always playing at one level higher than you...
Even after you've accounted for the fact that Eliezer is always playing at one level higher than you.
Reminds me of this.
In this case, yes.
Have we excluded the possibility of the Sorting Hat, either by accident or design, can help you violate the Interdict of Merlin? I mean, it doesn't seem to be alive under the sense of the terms of the curse, but you never know. And, also, personally, I've always thought it was peculiar that Ravenclaw didn't do anything to preserve his knowledge in the same way as Slytherin.
Rowena was a woman.
This doesn't really contradict your hypothesis, but the Sorting Hat is Gryffindor-aligned.
Could you explain what you mean by this? I know the original mundane hat the Founders enchanted happened to belong to Gryffindor, but I don't see how that's relevant.
In canon, the hat is considered a relic of Gryffindor specifically, which is why his sword can be drawn from it. The Wikia seems pretty clear on this, so we should expect EY to follow that. OTOH, Salazar managed to insert his own subroutine into the hat, so as I said, this doesn't really contradict cultureulterior's hypothesis about Rowena.
Quoth the wiki: It was a joint effort from the beginning. Also, do you think that the crystal rod thingy is actually Gryffindor's Crystal Rod Thingy?
Enchanting the hat was done by all four? Yes, I already tacitly agreed with you about that. But as you can see from your quotation, the Hat is still considered a relic of Godric's specifically. It is aligned with him. It is narratively imperfect for the Hat to serve individual tasks of other founders. On the other hand, Eliezer has already used it to serve a task of Salazar's, so it could do one for Rowena as well. That just doesn't fit as well. Nothing deeper than that. More likely his than anyone else's. But who knows, maybe it's Helga Hufflepuff's Crystal Rod Thingy, and then all four of them can have done something extra to the hat.

If Eliezer updates on the eve of the SAT, I'm going to track him down and read Vogon Poetry at him.

Will you do that before or after taking the SATs?

As a new lesswrongER, perhaps the most exciting thing about this community is the ability to reference Douglas Adams un-cited and assume that people will know exactly what I'm talking about.

Wow, which communities did you previously hang out in?

Welcome, both to LW and to the part of the internet where you can reference SciFi to your heart's content.
2Eliezer Yudkowsky
What's the eve of the SAT?
March 9, apparently. Although I don't see why this is important enough to consider. How many HPMOR readers do you expect will be taking the SAT on March 10?
5Eliezer Yudkowsky
Oh bloody hell. Well, now I have a cute little Moral Dilemma on my hands.
Huh? Looks easily resolvable to me. If disutility of Locke (possibly) doing significantly worse on his SAT outweighs the utility of hundreds (thousands?) of readers getting an HPMOR chapter a day early, release on March 9. Otherwise, release on March 10. Or, you know, release on March 8. No one would complain about that.
4Eliezer Yudkowsky
Moving on March 10th. Board meeting March 11th. Said I'd try to get to it by 11th. The SAT really matters to a lot of people's lives, though. But maybe some people would get a nice hedonic boost? Ugh.

I'm a reader who would not be directly affected by the timing relative to the SAT, and I say, please don't stick to the earlier date on my account. I would feel bad suspecting that other readers, who are taking the SAT, were harmed for my pleasure.

Don't know if I am a representative reader, though.

I agree.
How long does it take to post a chapter? o.O I'd have thought you could do it in 2 minutes of off-time.
7Eliezer Yudkowsky
My current plan is to try to do it during the Board meeting on Sunday. 7pm on Saturday I'll probably be driving, or if not driving, supervising a move with no Internet access set up yet.
Awesome. Thanks so much for making time for your enthusiastic and eager followers during what must be a hectic period.
3Joshua Hobbes
You have my gratitude. Do you think you can post a status update so people who don't browse Less Wrong can know? I'll get back to studying now.
Eh, if on March 11th the guy will have just moved, it'd probably take him significantly more than 2 minutes to just unpack his computer, set up his internet connection (if it has been set up all), etc, etc. Still, I'd tell him to leave it for the 11th, or even the 12th if that's not possible, rather than distract SAT students on the 9th or 10th. (Not that this relates to me personally, btw, I'm neither an American nor a student). He can leave a small note saying he leaves it for the 12th, if need be.
That possibility had just not occurred to me. Everyone I know has a laptop or a phone with internet access for when they're on the move. And I live in India. I'd have expected America to have better always-on internet connectivity.
I myself live in Greece and do have an IPhone with internet access, but I'd still not try to upload a whole chapter onto fanfiction.net with it.
Presumably the writing is the major factor. I doubt he's sitting around going 'where could I possibly fit in 2 minutes of Internet access?'
2Joshua Hobbes
He's already written all but the last chapter, I believe.
There you go, then.
What? Doesn't that mean it should be easy for him to post? Anyhow, we'd forgotten about the 7 pm rule.Reading between the lines here, he doesn't have any way of automating it. So not only must he find two minutes of free time, he must find two minutes of free time at 7 pm. And he doesn't have an internet connection while he's moving.

Harry and co. have one untapped potential ally: Lucius Malfoy. If they gave him all their clues, he may be convinced, just as they have been. And he has a powerful motive to find out who really tried to kill his son, even if he goes through with the trial against Hermione to avoid losing face.

The problem is how to approach him. He would not trust Dumbledore (his political enemy), Harry (he believes he is Voldemort and will soon hate him for 'turning' Draco), or Snape or Minerva (Dumbledore's agents).

I nominate Quirrel (to be sent by Harry) - known (or at least publicly displaying himself to be) free of Dumbledore's influence, a powerful Slytherin, and the one who actually saved Draco's life. Lucius would listen to him. Whether Quirrel would want to cooperate is another matter, but he should have some difficulty saying no to Harry and Dumbledore at once.

For Lucius to trust them, some of them might have to volunteer to testify in front of him under Veritaserum that they really believe the theory that Hermione didn't do it. Dumbledore is a known Occlumens, Snape and Quirrel would at least be suspected of being such, Harry told Draco he is so now Lucius knows as well. A weaker character like Minerva would be useless because Lucius could easily believe Dumbledore misled her. This is a problem...

0Joshua Hobbes
Lucius would obey a direct order from Voldemort, I should think. Maybe not from Harrymort, but if Quirrell could reveal himself...
If revealed as Voldemort, yes. But Harry doesn't know that Quirrel can do this, and Quirrel isn't going to volunteer that bit of information for Hermione's sake. Or do you mean exploiting Lucius' apparent belief in Harrymort? (Edit, see you added that.) I don't think he's going to obey an order from him. Maybe consider a request. Probably not even that, given his threat of destroying Harrymort if he hurt Draco, which by Lucius' lights he probably has while 'turning' him.
0Joshua Hobbes
Harry needn't know how Quirrell convinces Lucius. So if the professor really is innocent, and Harry threatens to end their relationship if Hermione is sentenced, then Quirrell might arrange a highly secret meeting with Lucius in order to preserve his grasp on the Boy-Who-Lived. If the professor is Hat and Cloak, he's probably going to be certain he's detained until the trial ends.
Why would Harry make such a demand unless he believed Quirrel could deliver? Do you imagine Harry asking Quirrel to Imperius Lucius, or mess with his memory? Harry's knowledge of such (presumed) acts would give him a way too big lever against Quirrel for as long as he continues under his Quirrel identity (which Harry would think is forever). Lucius or his allies might also find out and try to retaliate in the long term. And Quirrel has no personal motive to help Hermione. So while Harry would ask Quirrel for help (if he could reach him), he would not demand that particular help, not with a threat of severing their relationship. And I imagine that even if he did Quirrelmort would probably refuse. Agreeing to such a huge price just to keep their relationship would not be in character. Edit: I see now that you didn't specify Harry would ask Quirrel to act against Lucius, just to resolve the situation somehow. Still, if the observed result was a change in Lucius's behavior, and if later Lucius (through Draco) didn't supply a convenient excuse for it, Harry would forever wonder what presumably-political levers Quirrel could have at that level. Also, Quirrel clearly isn't leaving Auror custody until the trial and so Harry can't ask him and Quirrel can't act. Now that Dumbledore is using the map (and perhaps other means?) to search for, presumably, Tom Riddle on the grounds of Hogwarts, it's not clear how Quirrel can ever risk going back. I'd expect Dumbledore to keep checking the map once or twice a day, indefinitely, since he seems to believe it can find Voldermort if he's not in the Chamber of Secrets.

Harry already has (he would think) an ultimate lever: The breakout from Azkaban. If he so wished, he could inform Dumbledore and the DMLE and bring all the wrath of Britain down on Quirrell. It would mean incredible costs for Harry, but he could do it. Although, my mental model of Harry says that he would never actually do that.

Even as an occlumens, Harry could prove he and Quirrell did it. Harry has knowledge of Azkaban that no 10 year old should know. He can communicate with dementors to identify himself. He could recreate the rocket he used. Dumbledore can identify his patronus, etc. He's also got a good chance of getting off without many repercussions due to being a minor under someone else's influence and being the boy-who-lived.

Now, Harry doesn't seem like the trust authority like that, but he could pull it off. Heck, even if Quirrell wouldn't agree to help Harry, Harry could probably just lie and say Quirrell planned this against Hermoine and get this crime pinned on Quirrel if he really wanted to. I don't think Harry would actually do this, but it's a possibility. Harry has an untapped resource to save her that nobody knows about (Knowledge of the Azkaban heist), but he either wouldn't think of it or he'd consider it not worth it.

Harry also knows that Quirrell is an unregistered animagus.
0Joshua Hobbes
The thing is, If Quirrell is behind all this and is being detained unnecessarily is his plan, then Harry has got to realize that everything that has transpired has been according to his design. In fact, if he were H&C I'd expect him to be present so he could put on a show of doing his best to save Hermione. So it's very possible that the real culprit has planned for the professor's absence in order to turn Harry against him. That might be exactly what Quirrell will tell Harry when he is released post-trial, but frankly I don't see why he'd go through the extra trouble and cast doubt on himself just so as to avoid pretending to help. Unless, as you say, he is avoiding the map. However, the battle-map in 78 demonstrates that the Marauders did not invent the device. Thus, there is almost definitely one at the Ministry, where security is paramount. So if Quirrell did show up as Tom Riddle on such maps, he'd be assaulted by a hundred Aurors the moment he stepped foot on the premises. Therefore, I conclude that Quirrell is innocent.
The founders of Hogwarts created the map. Dumbledore considers the wards at Hogwarts stronger than those in the Department of Mysteries, so it stands to reason that all the aspects of the Hogwarts security system are stronger than those at the Ministry, including the map.
No, Fred and George think that Salazar might have created the map.
Dumbledore asked for the map, and used the sorting hat to procure a crystal rod which allowed him to manipulate it. It is an artifact of the founders.
Dumbledore didn't order the map to obey on his authority as Headmaster, he summoned a tool with which to fiddle with it. How do you know that crystal rods aren't a standard way to affect enchanted objects, and the one kept in the Sorting Hat is just unusually high-quality? I mean, if it was created by the founders, the Marauders would have had to do something very similar in the first place. So either Dumbledore undid the Marauders' alterations, or he altered their (or whoever's) creation the same way they would have had to, counterfactually. How do you distinguish between the options?
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Oh yeah. Uh, nevermind then. Out of curiosity, why the rot13? Did Eliezer retract this statement somewhere?
I think I got that information privately.
0Joshua Hobbes
Actually, if in MoR it doesn't mention Moody, Wormtail, Padfoot and Prongs, then the founders are a good guess.
0Joshua Hobbes
Ah. In that case the Ministry probably doesn't have one. Though I still doubt there's not a way Quirrell could get around it.
I think quirrel couldn't get around it because he might not know it even exists.
Yes. There are a couple routes he might have learned of it, though: * Slytherin's monster, as a high-level creature keyed into the deepest wards, might be expected to know of it or be able to learn of it. * If my speculation about the Map's anomaly is right, Voldemort's spirit could have learned of it by directly observing the twins. * The Map has been passed down through the ages and sometimes even been in official possession, so it could be mentioned in some obscure book. Possibly it might be a headmaster secret, explaining how Dumbledore learned of it without requiring him to invade their minds. * The twins could have been suspiciously - to Quirrel - adept at avoiding professors and obstacles, prompting him to spy on them as one would expect Quirrel to do. * The Map could be revealed at a future date; Quirrel's suspiciously good priors have long been speculated as being related to time travel. None of them seem especially likely, but in aggregate with other strategies I have failed to think of...
Well, it doesn't stand to reason exactly, but it stands to guess given a lack of contradictory evidence, at least.