Harry Potter and the Methods of Rationality discussion thread, February 2015, chapter 110

I guess now we know what Dumbledore was laughing about in chapter 17.

Oh yeah. 18 too, I guess:

"Of course you're in here blackmailing me to save your fellow students, not to save yourself! I can't imagine why I would have thought otherwise!" Dumbledore was now laughing even harder. He pounded his fist on the desk three times."

Worth noting - it is immediately after that laughter that he gives over his father's rock. And given that this chapter comments on how Dumbledore has access to wacky divination, that rock starts to make a heck of a lot more sense. (I mean, we always knew it's be an Important Quest Item, but this does shed a bit of light on why)

I guess now we know what Dumbledore was laughing about in chapter 17.

Amusing that you should bring up that chapter, Harry's lesson learned there seems somewhat relevant now...

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DO NOT MESS WITH TIME

Honestly, it sounds like sarcasm. Dumble is even stranger than usual this chapter.

I'm not quite sure it's the idiot ball, for two reasons.

1:

I would call it senility, if so many others had not missed it as well.

Even with the knowledge that Quirrel was possessed by Voldemort in canon, whether or not Quirrel was Voldemort was an active topic of debate among readers for quite some time.

2:

Really, am I that hard to recognize without the glowing red eyes? ... Quirinus Quirrell seemed - what is the term I am looking for? Ah yes, that is the word. He seemed sane.

If Dumbledore is used to thinking of Voldemort as a cartoon villain, and expects his shade to also behave like a cartoon villain, I could see him missing Quirrell.

(There is, perhaps, also the third reason of motivated cognition brought on by McGonagall, but I always saw that as more plausible if it were magically brought on by Riddle than her really not caring who he was.)

There's also the possibility brought up earlier and echoed in a lot of the other threads: this may be a Dumbledore spawned by the mirror as part of reading Quirrell's mind and determining his CEV. That doesn't explain how real Dumbledore didn't see it, though.

I'm not sure I agree. Everyone Is An Idiot Except Quirrel And Maybe Harry is a major theme of the whole series, not stronger than anti-deathism but certainly more consistent. Dumbledore bought the first level of Riddle's two-level bluff; in context that's pretty dumb, but not unusually so by MOR NPC standards.

I had been thinking that Harry needed to get some mileage out of being the true owner of the Cloak too.

If Tom Riddle is the true owner of the cloak the behavior of the cloak under various circumstances is unknown. But no times like desperate times for nondeterministic saving throws.

dying while wearing it would shield him from his own hocruxes or something?

holy crap, awesome you noticed this. Seems plausible.

Been thinking this through all day now.

Situation at the start of the school year: The stone is in the mirror, and it is anticipated Voldemort will be attempting to retrive it. Dumbledore is in possession of the true cloak of invisibility, and has "Flamel" on speed dial. Harry is known to be a harrycrux, which means Voldemort will either be taking over his body, or at least checking up on him.

There is no way Dumbledore gives Harry the cloak without anticipating Voldemort using it against the mirror. He wasn't obligated to hand that thing over to a first year, as opposed to hiding it under the proverbial rock in Greenland. Probability this was a misstep so low I can't be bothered to calculate it. It isn't just that he would have to miss the potential interaction here, every other person involved in building the trap would have to also miss it. For an entire year. So it's a plot.

This is the point where my certainties become less certain - I think what is going on is that the trap is set up to give Voldemort the false impression of victory at every step of the way while at the same time trying to take him off the board in various ways. This is being done to avoid him fleeing via blowing up Quirell's skull.

This means either Dumbledore was a fake of some kind or if actually there, that he lied through his teeth agreeing with every point of fact Quirrel brought up in order to convey zero actual information. Beyond that I thought of so many possibilities for what the actual trap could be that my head is currently spinning.

Option one : The True Cloak of invisibility is no such thing. They made a ringer. Option two: They flat out just cursed the darn thing. Option tree: The cloak has funny interactions with spirits, and the entire point is to kill voldemort while he is wearing it. Option 4.. you get the point.

I also think that there are likely plots in motion not related to the mirror at all - it would fit dumbledore's style to attack this problem at every possible point of intervention.

I am also fairly darn sure that Dumble knew or knows that Q is V - the phrasing used when professing surprise is just dripping with sarcasm.

I'm.. not at all sure Dumble actually has any unusual access to divination. See my earlier point about how he seemed to agree with every point of fact Voldemort raised, which has to be a disinformation tactic. Or the mirror just stroking his ego. Noone guesses that many things correct at this level of complexity on the first try.

Tom Riddle can't kill himself.

And two weeks later, Quirrellmort is back at the same power level thanks to his next-gen Horcruxes and can make a new attempt to get the cloak, while Harry (who is most likely the most notable rival Quirrellmort had) stays dead. Doesn’t sound too strong to me.

(Unless you value “Quirrellmort doesn’t get the cloak” about as high as “Quirrellmort doesn’t reach world domination”, which I don’t.)

My understanding:

Start: Quirrellmort is trapped in the reflected portion of Hogwarts; Harry is under the cloak and thus not reflected, but still trapped in Quirrelmort's ring; Dumbledore is on the other side of the mirror, unrestrained AFAIK.

Dumbledore starts the time-freeze on the Hogwarts side; Quirrellmort reveals Harry, takes the cloak and puts it on himself so he then doesn't have a reflection, and steps out of the reflected portion of Hogwarts.

Dumbledore reverses the time-freeze to act on his side to protect Harry. Dumbledore then disappears from the mirror.

End: Quirrellmort is free to roam about the physical world and has the cloak; Harry is still presumably trapped in the reflected portion of Hogwarts, but he is safe from the time-freeze; Dumbledore is frozen somewhere, but the Elder Wand and the Line of Merlin Unbroken have been left unfrozen as he cast them aside right before he disappeared; they are possibly now in the physical world with Harry and Quirrellmort.

[edited iteratively]

Are we sure that that is a binary answer?

A satisfying victory against an opponent just one move behind... Sure seems like Q's desire.

Only thing is this doesn't explain why Harry can see it. I'd say it has to do with the Riddles being the same person, but that would mean a mere confundus broke that link? Is it possible Voldemort was able to get the true Quirrell to confund himself? This seems improbable.

More likely what we saw was special programming of some sort, keyed to a trait common to the Riddles, and not just a normal desire show--though not necessarily what it appeared to be.

Dumbledore is human (or, at least, wizard). He hates Voldemort, who has killed thousands. He has motive to talk to him to keep him there long enough for the Fixed Instant to trap him. The temptation to spend a little of that time insulting Voldemort is too much for even his self control to resist.

Voldemort, by contrast, is just playing with him, letting him waste time till he won't be able to cancel the Fixed Instant, such that when Voldemort grabs the True Cloak of Invisibility Dumbledore will have no choice but to choose who dies forever, the "good Voldemort" or himself. Its very similar to how he toys with Rita Skeeter before murdering her.

Meh. The big Dath Bey Yewoonen prophecy may not apply to this one, but Harry will certainly consider this to be "death" for his purposes - and Harry does not intend to leave anyone dead.

And what magic can do, an immortal rational wizard can undo...

Odds of Dumbledore actually being dead?

He's not dead; he's just out of time. It seems likely that Harry can restore him, if he manages to make it out of this alive and with his values intact.

The Mirror in canon isn't limited to the viewer's knowledge (cf. the appearances of Harry's extended family); it's unlikely that the HPMOR version has been given that limitation, so fulfilling that limitation is not a strong indicator. Moreover, Quirrellmort's CEV probably is not to defeat Dumbledore, so the Mirror should not show it. I think odds are high that this was the real Dumbledore, and that he has been, not killed, but cast out of the time stream. Removed from game, if you will.

It seems like Mirror-Dumbledore acted in accordance with exactly what Voldemort wanted to see. In fact, Mirror-Dumbledore didn't even reveal any information that Voldemort didn't already know or suspect.

Which is exactly how the mirror was always advertised to work?

Also, Dumbledore mentioned how he laughed when he found out that Harry was a good version of Riddle, which many readers have taken to refer to this scene in Chapter 17:

Dumbledore started laughing. Laughing a lot harder than Harry would expect, almost howling. It seemed positively undignified. An ancient and powerful wizard ought to chuckle in deep booming tones, not laugh so hard he was gasping for breath. Harry had once literally fallen out of his chair while watching the Marx Brothers movie Duck Soup, and that was how hard Dumbledore was laughing now.

"It's not that funny," Harry said after a while. He was starting to worry about Dumbledore's sanity again.

Dumbledore got himself under control again with a visible effort. "Ah, Harry, one symptom of the disease called wisdom is that you begin laughing at things that no one else thinks is funny, because when you're wise, Harry, you start getting the jokes!" The old wizard wiped tears away from his eyes. "Ah, me. Ah, me. Oft evil will shall evil mar indeed, in very deed."

This was a scene that Quirrell was most definitely not present for, and thus the fact that Mirror!Dumbledore knows about it further suggests that Mirror!Dumbledore was not simply some CEV-illusion of Quirrell's.

In the latter case he must have valued Harry instrumentally more than himself, as he said before that he would not be deterred by hostages. (Though he could, of course, have been bluffing.) That seems somewhat odd though, given that Harry is currently unarmed and at the mercy of Voldemort.

Remember that Dumbledore is truly willing to sacrifice himself, and he has access to a number of prophecies. He likely knows that this is the right call, both by his altruistic morality and whether or not it will lead to Voldemort's defeat.

(He also probably correctly thinks it is more likely that Harry can rescue him from being frozen than he could rescue Harry.)

Does Quirrell have the Resurrection Stone? If so, that's 3/3 Deathly Hallows (invisibility cloak and elder wand).

My reading was that he threw the objects aside, not through the mirror, so they got sealed together with Dumbledore's pocket mirrorverse (a mirrorverse... he must have been hiding a goatee under that fake beard!)

... Is it just me, or is Harry Potter now in the same room as the Elder Wand and the Philosopher's Stone?

... Well, there's a great big Dark Lord in the way, but.

Also Dumbledore's scepter-thing (Line of Merlin Unbroken?), if that has any power.

The old wizard looked back up at Harry, and said, in a hoarse voice, “He is not like Grindelwald, Harry. There is nothing human left in him. Him you must destroy. You must not hesitate, when the time comes. To him alone, of all the creatures in this world, you must show no mercy; and when you are done you must forget it, forget that you ever did such a thing, and go back to living. Save your fury for that, and that alone.”

We've seen that Dumbledore has worked very hard all his life to be wise and compassionate and generally fit the archetype of the true hero. I can't help wondering if Voldemort is the one person he allows himself to truly hate, which is why that hatred is unusually intense and fully brings out Dumbledore's otherwise unseen dark side (or as fully as Dumbledore has one, which is still less intense than most people's when faced with someone who's hurt them that much).

If you feel any sympathy for Riddle at all then that's not funny, it's tragic

I was wondering how EY would play this. For my part, the "pity me, I couldn't help being me" argument is not very compelling. He is what he is.

One wonders what Dumbledore's "unusual power of Divination" is.

I had assumed that he was busy faking divinations strategically.

I love the image of Dumbledore gloating like a cartoon villain. You're right, of course.

Self-consitant time travel seems far harder to simulate than CEV.

would he be able to metabolize proteins? Carbohydrates? Fats? Nucleic acids? Are there any essential amino acids Harry will be missing?

Only metabolizing fats, glycerol, and the simplest amino acid, glycine. Everything else is chiral, including a hell of a lot of vitamins. Mirror sugars still taste sweet though. I have no idea if mirroring a protease changes its ability to digest protein (for all the good liberating mirror amino acids would do) but know nucleases and starch-degrading enzymes would be useless.

Though for energy alone he could also consume alcohol, acetic acid (think vinegar), and some ketones and aldehydes that are pretty nasty in large quantities but you can get some cellular energy from like acetone. Unable to get any of the essential amino acids histidine, isoleucine, leucine, methionine, phenylalanine, threonine, tryptophan, valine, or lysine.

Regular bacterial cell walls contain a few mirror amino acids produced enzymatically during wall production - mirrored glutamate, glutamine, and alanine. Not gonna be much. You could probably make about half the nonessential amino acids internally by drinking VERY VERY dilute ammonia (or thicker glycine) and eating fat/alcohol/acetic acid, and the other half of the nonessential ones by drinking VERY VERY dilute ammonia (or thicker glycine) and VERY VERY dilute acetone. Don't quote me on that, amino acid metabolism is cellular witchcraft with a few rules of thumb to me compared to central carbon metabolism where I do my work. The acetone would also allow things like the production of carbs internally for the purposes of connective tissue renewal and the like faster than the weird still not quite understood in animals very slow production of sugar from fat breakdown products. Though your kidneys and liver would probably fail long before anything in this list was useful.

If the mirror universe was antimatter, Harry would be annihilated instantly because his feet are touching the floor, even if the Cloak could shield everything else.

The source of the Harry-Voldemort resonance is that Harry was made into a Horcrux of Voldemort. Chapter 108:

The prophecy seemed to hint that if I destroyed all but a remnant of Harry Potter, then our spirits would not be so different, and we could exist in the same world."

"Something went wrong," Harry said. "Something that blew off the top of the Potters' home in Godric's Hollow, gave me the scar on my forehead, and left your burnt body behind."

Professor Quirrell nodded. His hands had slowed in their Potions work. "The resonance in our magic," Professor Quirrell said quietly. "When I had shaped the baby's spirit to be like my own..."

Harry remembered the moment in Azkaban when Professor Quirrell's Killing Curse had collided with his Patronus. The burning, tearing agony in his forehead, like his head had been about to split in half.

"I cannot count how many times I have thought of that night, rehearsing my mistake, thinking of wiser things I should have done," said Professor Quirrell. "I later decided that I should have thrown my wand from my hand and changed into my Animagus form. But that night... that night, I instinctively tried to control the chaotic fluctuations in my magic, even as I felt myself burning up from inside. That was the wrong decision, and I failed. So my body was destroyed, even as I overwrote the infant Harry Potter's mind; either of us destroying all but a remnant of the other.

Presumably that they're equal but opposite.

I think we finally have a good explanation for Harry's Father's rock: Dumbledore's mysterious divination power. He somehow knows the rock will be important, but perhaps not exactly how or why.