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 story and want to preserve as many surprises as we can for as long as possible. We want to wait, wait, wait for a bigger payoff later.

I think Eliezer is likely to be silently rolling his eyes at us on this, thinking "There they go again!" and chuckling quietly to himself. But I know that if he is, he's darn well going to let us figure it out for ourselves this time, rather than once again holding our hands as we step gingerly to conclusions to which he meant us to leap.

So, maybe H&C is Padma!!1!

sigh. Can we please let this idea die already?

Downvoted for the attitude. People in LessWrong generally understand the difference between "evidence" and "indisputable proof".

When you say that "we should let this idea die already", are you actually claiming that the similarity of the H&C and Quirrell statements in regards to Slytherin's monster is exactly zero evidence towards H&C and Quirrel having some connection between them? Are you really saying that the author is exactly as likely to have H&C and Quirrel use the exact same phrase in regards to Slytherin's monster, if they were the same character, and if they were completely unrelated characters?

If you're not saying that, then all you're saying is that you feel it should be weighed as less significant evidence than how some people are weighing it -- but a mere disagreement on how it should be weighed doesn't justify your tone or the way you say "please let this idea die already".

Assume Quirrell is not able to model 'good' people well -> we know he is not all powerful, and this is certainly where he is weak - witness conv with Harry on 'give a finger of my wand hand', 'does it really matter what your friends think', etc.

And each iteration with Hermione could have brought a different reason from Hermione, which was then subverted - we only saw one arc. Also H&C wanted Hermione as a willing participant, not as an NPC, much harder than simply memory charming her.

It's very unlikely EY has used two different H&C, and there was the 'wards keyed in' statement of both H&C & Quirrell earlier.

Will need much stronger evidence to say Quirrell is not H&C.

Any reason(s) in particular that you're certain that Horcrux-creation would have detrimental effects significant enough that Voldemort would create only one, maximum? I assume it must have some detrimental effects, because otherwise, given a Rational Dark Lord armed with a time-turner, we'd be looking at Horcruxes proliferating as fast as he can make them. Tens or hundreds or thousands of horcruxes, one on every muggle device launched into or out of orbit, if he could manage it.

I notice that you seem to take for granted the existence of "souls" in MoR, which is far from certain. Actually I would rate the possibility as decidedly uncertain, since if souls and their attendant afterlife existed, it'd put quite a dent in the entire motivation for Harry's "conquer death and achieve immortality for everyone" program. And as prasannak noted, Harry has raised the alternate hypothesis that horcrux creation is less soul-fragmentation and more mind-uploading: "Maybe he found some way of duplicating the power of the Resurrection Stone, only he loaded it in advance with a complete copy of his brain state. Or something like that." (Chapter 39)

edit:

And I just remembered a brief exchange between Quirrell and Harry in chapter 46, which (to me, at least) hints at the existence of more than one horcrux. Quirrell asks Harry, hypothetically speaking, where he would choose to "lose something where no one would ever find it again." (I assumed he was being all ironic again and was talking about horcruxes.) Harry reeled off a list of about 5 possible hiding places, to which Quirrell responds "All excellent suggestions... But tell me, Mr. Potter, why those exact five? ...There is an interesting pattern to them.... One might say it sounds like something of a riddle." (Riddle? Irony overload.)

It just dawned on me that those 5 hiding places could only be clues to a riddle (the riddle of where Voldemort chose to hide all his horcruxes) if they didn't encompass the complete set of all horcrux hiding places, meaning that there are probably more than 5. Additionally, those 5 hiding places would only be good "clues" if they were themselves correct hiding places, from which further hiding places could be extrapolated based on some sort of shared similarity.

I think you're underestimating how guessable things can be if one pays attention to clues. I can't remember for sure, but I think the possibility was in my mind since I first read the note about how Harry should have noticed his confusion about the story.

The list of evidence I gave in favour of that position in a Hatrack forum discussion back in November 2010 was simply that
a) We're told that Harry should have noticed something off about the story, but he didn't (simplest thing he should have noticed is: how the hell do people know what Voldemort tried to do, if there were no living witnesses)
b) Avada Kedavra normally leaves no mark on the victim. Whatever was done on Harry left a lightning-shaped scar.
c) Avada Kedavra kills anything with a brain and never rebounds. This time it's supposed to have failed to kill Harry and to have rebounded onto Voldemort.

All of these were well known before chapter 43.

Since then we can add the evidence of:
d) Bellatrix indicated she was given Voldemort's wand before Voldemort went to the Potters' home -- simplest explanation was that Voldemort didn't want his wand taken away by Aurors when his physical form was destroyed, and so he knew his physical form would be destroyed.
e) Lucius Malfoy seemed to believe Voldemort resides inside Harry's body, which is a rather odd conclusion to arrive at, unless he already has reason to suspect Voldemort wasn't attempting to kill Harry.

These pieces of evidence are not in chapter 43 either.

What evidence are you talking about that's in chapter 43?

Some weeks back I placed a prediction about this subject at http://predictionbook.com/predictions/3237 . Check it out, if you want.

So. Ch76, the part about how prophecies work. Has anyone else seen the connection to Amputation of Destiny?

I've already posted this in the reviews as well as on TvTropes, but I figure it can't hurt to share it here as well. (As well as pose it somewhat more formally.)

Harry's freak-out in the beginning over the animagus transformation got me thinking. Between the two possiblities: a) the laws of physics Harry believes are wrong and b) the animagus transformation only appears to violate Conservation but doesn't actually do so, it seems fallacious to skip to possibility-a without ruling out possibility-b.

After some thought, I was able to generate a hypothesis for how Variable-Mass Shapeshifting Between Multiple Fixed 3-Dimensional Structures might work without violating Conservation; I don't know enough about physics to guess if it is plausible--One of the clues I'm basing this guess on was that Harry did not in any way remark upon the existence of containers that are bigger on the inside than on the outside, and the inference that magic can create space and that this does not violate any law of physics that Harry knows of.

The two or more 3-dimensional forms with differing mass all exist simultaneously in an unchanging 4-dimensional superstructure. The form that is perceivable in our 3-dimensional universe is whatever cross-section of the superstructure happens to intersect our 3-dimensional grid, and "changing form" involves only unidirectional motion along the inferred extrauniversal axis.

VMSFF = Variable-Mass Shapeshifter with Fixed Forms

Possible Evidence for:
* VMSFFs rarely have more than one alternate form. (Magic has to create space for each alternate form on the 4th spacial dimension. No indication that additional space does not require additional energy to maintain.)
* VMSFFs transform quickly. (Same reasoning as above: there is as little intermediate matter as possible.)
* VMSFFs demonstrate similar cognition regardless of form. (Suggests both brains are present and active at all times.)

Possible Evidence against:
* Dementor effect is less in animal form. (Suggests that either both brains are not equally present, or that Dementor Effect is constrained to 3-dimensional space.)
* Animal urges change with the form. (Suggests that both brains are not equally active. Weak evidence, as bleed-over of urges between forms is observed.)
* Injuries in one form translate to the other(s). (Suggest the two forms are not separate parts of a larger entity.)

Tests:
* How is an animagus form destroyed? (Is it closer to Amputation or Obliviation?)
* Does wearing heavy clothes vs. nudity affect the amount of energy necessary to transform? (Does the difference in energy match the inertia of the clothes?)
* What does the change feel like to the animagus? (Is it sensationless as switching from one set of sensory imputs to another would suggest, or is it sensable as having sensory imputs within changing matter would suggest?)
* In the case of the Wolves in Luminosity, is the mass of consumed food greater than the mass of the Wolf's human body plus waste? (If so, does the cumulative difference match the mass of the Wolf upon first Floof? For animagi, does the magical energy expended to create the alternate form in the first place match that needed for the transfigured-creation of a similar mass?)
* Is being an animagus a permanent drain on one's power?

In any case, I've been thinking about it for a while and a 4-dimensional superstructure is the only way I can imagine it working. Alternate Hypotheses anyone?

The infodumps are not what I'm talking about. I wouldn't believe it's Eliezer's writing if people weren't smugly going on about eigenvectors. My concern is that Harry is a complete asshole. And the unrealistic adults.

Eliezer addressed it here

If you saw a character talking like that in a published SF novel, you would know that he was an alien or genetically engineered or that the author meant you to know something was funny about him. In fanfiction they assume that it's either the author's conceit or, more probable yet, you're just a terrible author who can't write realistic eleven-year-olds. I thought it was so blatantly lampshaded that nobody could possibly mistake it for an accident, but no, fanfiction readers just don't think like that - they don't look for clues and they do assume lousy authors.