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Time travel isn't fully computable

Depends on what kind of time travel and what kind of universe. Heck, even classical newtonian real-valued physics is not computable (but is computable to arbitrary precision). If the information content of the universe is finite (like, it is a grid of finite many cells, each of them could be in only finite many states, and time is discrete as well), then time travel is computable - you just have to store the information for the past 6 hours and brute-force consistent stable loops.

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9 Harry Potter and the Methods of Rationality discussion thread, February 2015, chapter 109

by Gondolinian

23rd Feb 2015

1 min read

162

9

This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 109.

There is 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. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)

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Eliezer Yudkowsky which is not supposed to be publicly available (which includes public statements by Eliezer that have been retracted).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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Harry Potter and the Methods of Rationality discussion thread, February 2015, chapter 109

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[-]Izeinwinter10y370

Dumbledore isn't in the mirror. Harry and Voldemort are. The trap triggered, stuck them in a time-dilated mirror plane. Which is, of course, the only reasonable way to deal with an immortal serial killer. This even counts as fulfilling the darn prophecy, doesn't it? Definitely if Dumbledore can extract Harry, because that way naught but a remnant will exist in the same world, and yes, it does count as Harry defeating him. He talked him into stepping into that trap, after all. Bravo.

[-]Transfuturist10y250

This would be amazing. The last chapters could be the HPMoR version of the AI Box experiment, where Quirrell is an Unfriendly Optimizer, Harry is a Questionably Friendly Optimizer, and Dumbledore is trying to get Harry out.

Perhaps Eliezer might finally reveal his secrets...?

Probably not. But that problem would be such a neat way to end the series. Quirrell could pull tricks, and we'd see a no-holds-barred speed chess match between Quirrell, Harry, and Dumbledore.

[-]solipsist10y140

Oh dear. Harry's in there, Hermione's body is in there, Quirrell has the Philosopher's stone, and he can hum! I hope the protagonists are good gatekeepers...

8Nornagest10y

This is totally cheating, but if that were the case, I don't think there would be 11 chapters' worth of plot left.

0skeptical_lurker10y

There's also many other plot strings that need to be tied up.

0Ander10y

I think there could definitely be a few chapters of resolving the mirror plot followed by a few chapters of wrapping everything up.

8Astazha10y

I love this. Bravo to you as well! ETA: Now I'm sure you're right.

3somervta10y

sure? how sure are you, and how much do you have to bet?

1Astazha10y

Betting isn't my thing. I know it's popular among many here, but I'm just on the forums to discuss HPMOR with other fans. There are other possibilities, like Harry is seeing what he desires, but I have to propose some pretty awkward complications to make that work. I think Izeinwinter is very likely correct.

0Michael Wiebe10y

When Harry first entered the room wearing his cloak, he looked into the mirror and saw only the reflection. Now he is again looking into the mirror while cloaked.

3Michael Wiebe10y

Dumbledore is in the mirror. Quirrell, from 104:

2levantis10y

What if it's the dying confunded ego of Dumbledore desired to be alive the most, summoning real Dumbledore?

[-]solipsist10y290

Harry had applied the Charm he'd learned for battles that made his eyeglasses stick to his face, regardless of how his head moved.

(Chapter 104)

The first thing Harry had to do was strip off all his clothes, and his shoes, and everything else he was wearing except his glasses; without his wand, Harry couldn't unstick his glasses from his own forehead, and neither could Professor Quirrell because of the magical resonance.

(Chapter 109)

Just pointing out: Hermione's body is probably Harry's glasses.

2Jost10y

I don’t think this is further evidence. The magical resonance could be caused by the sticking charm, as well; no need for the glasses to contain traces of Harry!magic.

6lerjj10y

It's not further evidence, but it's a good suggestion for a possible place for Hermione to be. It's safe from Quirrell and unexpected. It's also partially hidden by a different charm (assuming QQ can sense Harry's magic)

6Scott Garrabrant10y

It is literary evidence, because EY is talking about the glasses.

0Ben Pace10y

It is further evidence, because it's the only thing still in contact with his body.

2tegid10y

Why is that further evidence? Transfigurations last for a time, whatever Hermione is transfigured into, she would not revert just because it stopped to be in contact with Harry's body. For the record, I think it very likely that Hermione is the glasses

0Desrtopa10y

I forget, do we have any word on whether damaging an object someone has been transfigured into would affect its ability to retain their information? Glasses have a rather limited operational lifespan- I broke another pair just recently.

5DanielLC10y

Did you enchant your glasses to be unbreakable? I imagine that would be standard in a magic school.

0Desrtopa10y

Well, Harry breaks his glasses in the canon books, because nobody ever does anything sensible, but as a more general rule, if you could simply transfigure people into objects and enchant those objects to be unbreakable, and thereby prevent damage to their body structure, human transfiguration would already be possible within ordinary means.

1DanielLC10y

It wouldn't completely prevent damage, but it will prevent any damage that would be noticeable on top of the significant amount of damage Hermione has.

0kilobug10y

My understanding is that "unbreakable" magic makes the object unable to change at macroscopic level, but doesn't prevent small alterations at microscopic level. And those small alterations at microscopic level, in case of a transfigured human, will lead to DNA damage and similar things. It's not known if the information encoded in the brain will resist or not - it's much higher level than DNA, so there is a good chance it would.

0Subbak10y

Another possibility if that "unbreakable" works fine on things that have very few moving parts, but if you try that on a human body then they become utterly incapable of changing. Their muscles don't flex, which means they can't breathe and their heart stops beating, and they die very quickly.

0[anonymous]10y

Asking me that question is a blatant violation of the rules of transfiguration! But here's what I remember from Chapter 15

[-]bramflakes10y240

I show not your face but your coherent extrapolated volition

I got shivers when I read that and realized what the Mirror was. Another thing that ought to have been obvious, in hindsight.

[-]wwa10y160

And the entire HPMOR fanbase has just now googled the concept. Promotion of ideas is what HPMOR's purpose is, after all.

8Bugmaster10y

Product placement at its finest...

1Gondolinian10y

Why do the runes correspond to arbitrary clusters of characters, and not words or concepts? [edited]

[-]Vaniver10y150

What's with the weird spacing breaks though? It's obviously meant to be read and not a code, though

To mirror canon, where the mirror's inscription is:

Erised stra ehru oyt ube cafru oyt on wohsi

[-]Jost10y110

Spacing is equally weird in canon: “Erised stra ehru oyt ube cafru oyt on wohsi” So, probably just a relic from canon …

1lerjj10y

Is my vocabulary at fault here? I'm parsing that as "I'm not actually reflecting you [already known], but instead I'm reflecting what I think you want me to" This sounds like a description of the Mirror from canon. What have we learned that's new?

5Jost10y

It probably doesn’t refer to “coherent extrapolated volition”, but to “Coherent Extrapolated Volition”.

0lerjj10y

now I feel stupid for not doing a google search to see if parts of that sentence were recognised phrases. Of course that's what it means. In fairness though, this is simply a FAI refinement of my first reading- it doesn't show what it thinks you want, but somehow scans your utility function and calculates what to show you. Either way, the Mirror of Erised still seems to be pretty much standard.

[-]linkhyrule510y120

Not quite. It won't show you what you think you want, or even what you really truly want this second - it shows you what you would want, if you were were better, smarter, and more the person you wished to be. It's coherent - you should never look into the Mirror and go "on second thought, that's a terrible universe."

For example, Ron would not see himself becoming Prefect or being Head Boy, because in a decade or less he'll have outgrown such ambitions.

0Ben Pace10y

Well... Dumbledore sees his dead family (well, Quirrell thinking he's Dumbledore sees Dumbledore's dead family). Which is like Ron seeing everything he currently wants, rather than utopia.

9SilentCal10y

Could be because this mirror doesn't extrapolate very far, could be because Quirrell's fake Dumbledore doesn't have full human wish complexity.

5[anonymous]10y

Strikes me as most likely explanation by far.

2Nornagest10y

Not quite. It's more like Ron seeing what a more mature version of himself would want, but Dumbledore's pushing 200 and famously wise; he's not going to get much more mature following the path he's taken. You could argue that his worldview isn't self-consistent and that a smarter or less self-deluding version of him would pick up on that, but that seems like it bakes in a conclusion. I haven't exactly formalized this, but I have the intuition that CEV would be doing more work in aggregating extrapolated values than in extrapolating values in the first place. We can't just have it wave a wand (har) and rid ourselves of heuristics and biases to find our true values; too much of human value is wrapped up in those same heuristics and biases, and from an internal viewpoint none of them are any "truer" than any others. We can envision an aggregation process that plays different people's heuristics and biases against each other in some way to find a least-worst kernel of value; but to do that, it needs those data points.

0Luke_A_Somers10y

Another part of coherence is that, for groups, it's supposed to reconcile differing viewpoints - to only act on what's shared.

7cogitoprime10y

Sooo it could show the coherent desires shared between all Tom Riddles?

3gwillen10y

At first I thought that fact did not seem interesting, since it's not really expected for more than one person to be looking into the mirror at once. But then I considered that, as the chapter closed, the mirror appeared to be speaking to BOTH Tom Riddles, and now I'm curious what their collective CEV looks like.

[-]SilentCal10y230

I'm having trouble making sense of the Mirror. Atlantean-MIRI built a CEV-viewer to guide the massively powerful optimization they were planning to unleash, sure.

But it's not just a viewing device; you can put things in and take them out. Why? Unsatisfactory answer: So you can step inside and live out your life in the room of your heart's desire. Unsatisfactory because you might want more than one room.

Also, every viewer doesn't get a freshly minted instance of their CEV; it's possible for them to see the effects of someone else's prior interactions with the world. Why? Answer 1: Because storing things in the mirror was an intended use. But why? Answer 2: People whose CEV dictates they live together, with the real versions of one another and not convenient copies, need the same instance of the same world.

If the Mirror is the source of phoenixes, then the mirror can be used to create things. Maybe the idea was to produce the singularity within the mirror and take it out? The world doesn't look like this happened, and I doubt EY's ending is that no one really wanted a singularity, but maybe there's some limitation that prevented this. Say, the Mirror piggybacks off the user's brainpower, so it can't extrapolate its way to a much Friendlier singularity than the user could have designed. I do take the mirror's performance so far as evidence it doesn't extrapolate very aggressively.

6DanArmak10y

The mirror isn't infinitely powerful. That's not an unsatisfactory answer, it's an unsatisfactory attempt at FAI. Quirrel does say the mirror was never completed, or at least wasn't the final goal of those who built it. Because the mirror has limits, it can only create one room (at a time); if it could create whole universes it would be absurdly powerful. As for letting viewers interact with other viewers' creations, that sounds like a feature, not a bug. If the mirror was used to find out what the CEV of a viewer was, then it was useful for other researchers to observe it and take notes. A person viewing their own CEV would be a partial, unreliable reporter.

[-]MathMage10y190

Prediction: Atlantis wasn't a catastrophe that the Mirror was too late to avert. Rather, the Mirror was completed, and the Atlanteans removed themselves to a realm of existence within the Mirror. Confidence: 5%.

7jimrandomh10y

Far more likely that there was a catastrophe, and the Mirror itself was the cause.

2MathMage10y

Yeah, that's a good way to turn all this "carefully designed not to destroy the world" stuff on its head.

0buybuydandavis10y

The narrative also serves to reinforce MIRIs basic premise, that AI could destroy the world.

7Bugmaster10y

Either that, or the world where HPMOR takes place is just one among many realms within the Mirror; i.e., the Simulation Argument is true, and the Atlanteans are the Matrix Lords. This explain the weird and inconsistent magic rules: they are just artificial constructs that the Atlanteans came up with on a lark.

1DanielLC10y

Didn't Harry already point out that the time travel was not computable, and as a result it couldn't be a simulation? Although he didn't go to great lengths to prove that. He assumed that there was no force subtly manipulating events to make sure time travel is consistent. In fact, he is in a simulation run on the computer that is Eliezer's brain.

3Bugmaster10y

I don't know if he put it into exactly those terms, but a). Harry points out a lot of things that aren't true, like "you can't turn into a cat", and b). if the laws of reality are simulated, then they don't have to make sense; they could just be a giant "switch" statement somewhere in the Atlantean VM code.

0DanielLC10y

If the laws of reality are simulated, then they must be computable. A giant switch statement isn't going to let you figure out how to make time travel consistent. They couldn't easily check every possibility and see if it's consistent. Even if they did, that would mean they're simulating all of them, including the inconsistent ones, and there'd be no reason for Harry to find himself in a consistent one.

4Bugmaster10y

Why not ? It's not like the laws of our space-time apply to them or anything.

[-]Jost10y180

Atlantis-Human: “Where did you learn about computability, Harry?”

Harry: “… in the Matrix.”

A-H: “The Matrix tells elegant lies.”

2alienist10y

Depends on what they're being stimulated on.

0Astazha10y

The anthropic principle solves Harry finding himself in a consistent one nicely. We don't know about the paradoxical universes because time/magic destroys them. You could also propose that when paradox occurs time goes back to the point of paradox and makes changes, inserts prophecies, etc. (maybe even uses mind magic?) to attempt to correct, destroying only the portion of the time-stream that came after. In this version there is actually just one time stream, not many, and it loads from the last checkpoint so to speak whenever a paradox results. Results like "DO NOT MESS WITH TIME" really imply an outside intelligence that is meddling to ensure consistent outcomes, rather than a universe that runs only on physical law. This isn't a reponse Harry would have thought of, it was inserted from somewhere external. Regarding "computational difficulty": 1) We don't know what magic/time/the external universe is capable of, computationally. Magic does "impossible" stuff all the time. 2) It doesn't matter how difficult it is to compute or how long it takes. These things are transparent from an inside perspective. 1 second in-world could take a billion years to calculate, and it would still seem seamless from the inside.

0avichapman10y

It the simulation were infinitly parrallel and all simulations that weren't consistent crashed, the Harry that made the observation about the loop would necessarily be in a self-consistent simulation.

2kilobug10y

Time travel isn't fully computable, but that doesn't mean it can't be approximated, that you can't make hacks giving the impression of time travel to people inside the simulation. It might even be possible that attempts to abuse time travel (like the one done by Harry at the beginning when he tried to factorize primes using the Time-Turner) raise an alert in the simulation, freezes the simulation until an operator manually inputs an acceptable solution ("don't mess with time" being the solution hand-crafted by the operator).

2garabik10y

4Ben Pace10y

Thing is, on that line, this would sorta become a simulation fic, and Yudkowsky said it wasn't that.

0savedpass10y

Didn't he also say there wouldn't be AI in it?

1Ben Pace10y

I think he said 'Harry won't create an AI' but I don't have the source.

0drethelin10y

I don't think it's really a simulation fic if simulations exist but the main story level isn't in one.

0Subbak10y

And changing the genre when the story is over 90% complete would be a questionable move.

1lerjj10y

This was what I thought as well. I doubt we'll get confirmation of that prediction though, unless Quirrell/Harry actually DOES try to destroy the world. In which case presumably the Atlanteans have to save the day (unsatisfying from a literary point of view, hence unlikely).

[-]Izeinwinter10y160

BTW, not related to the plot much at all, but I think I get the point of the dungeonrun first year students can beat.

The mirror is set to show students their CEV, which Harry dismissed as "Themselves in some very desirable situation". Is dismissed the right word? Eh, anyway, I don't think the people Harry talked to quite managed to convey the magnitude of it to him.

Slytherin's core insight, the thing his house if founded on, is that people become who they are supposed to be by pursuing their ambitions, or at least that is the opinion of Quirrel the teacher-persona. I don't actually care if he truly believes that, because it just strikes me as an important truth.

The mirror tailors good and sound ambitions for people. Or at least it does for any student which has a CEV which could conceivably be achieved via their own efforts. And they are, after all, witches and wizards.

Putting it behind an obstacle course makes people value and pay attention to what it gives them. It is a really impressive piece of pedagoguery.

So basically, the entire thing isn't about Voldemort at all. It's about teaching. Wonder how much of slytherin house did this run? Because it obviously is the house that would benefit the most from it.

1Leonhart10y

"This mirror can help us get our Cutie Marks!!" sorry

[-]WalterL10y110

So, is that really the stone? Was "triumphant Dumbledore" enough to get the mirror to coff it up, or is that a trap of some kind?

My thinking is trap. Dumbledore doesn't believe he can best Voldemort, he thinks Harry will, due to prophecy. He's set up the mirror to give him a false Stone if he appeared in front of it thinking that he'd won, because he believes that if that was the cases he'd have been deceived.

Further guess, the mirror's actual condition for giving up the stone is that it will give the stone to a phoenix.

2lerjj10y

But Dumbledore doesn't necessarily expect to live out any encounter with Voldemort, does he? And Harry's lost his chance of a phoenix

7WalterL10y

Right, so, by Dumbledore's thinking, if he shows up having beaten Voldemort then he's not real. He expects that Voldemort would kill him. So the mirror could be a trap for any "triumphant Dumbledore" who appeared before it. This is particularly true because Dumbledore doesn't fear death. He could easily have made himself forget the trap. If he wins and is killed by his trap, what's the harm? Its just the next great adventure. To actually get the Stone probably just needs some terminal values equivalent of the arbitrary physical description Harry gave. A crazy person Dumbledore happens to know who thinks they are the only person in the world. Someone who doesn't know anything about the mirror at all. The possibilities are endless. Flamel himself is the obvious choice, identified as a person who knows some bit of trivia (s)he learned in 600 years alive.

[-]DanielLC10y80

Dumbledore has argued that death is good. We have all assumed that this meant he thought death is good. I'm beginning to question that assumption. Dumbledore's stated belief has given him access to the Philosopher's Stone, and resulted in Voldemort going to the Mirror with a specific state of mind. Both of those are very useful conditional on Dumbledore considering death to be bad.

Admittedly, he probably didn't predict the second one, but it's entirely possible that Dumbledore had been claiming that death was great for his whole life in hopes that one day the holder of the Philosopher's Stone would give it to him for safe keeping.

[-]Vaniver10y80

I'm not quite sure how to interpret the end of the chapter. Option 1 is that real!Dumbledore is within the mirror, option 2 is that Riddle!Dumbledore is within the mirror (and about to interact with Tom in the way Tom always wanted him to), option 3 is that real!Dumbledore is outside the mirror and Harry can see him reflected in it.

[-]solipsist10y160

I bet on option 1. I think Quirrell has been expecting Dumbledore to be hiding in the mirror. He said:

[...]I saw the Headmaster missing... but for all my magic can tell me... he could be in another... realm of existence..

Quirrell could be lying, but Dumbledore being hidden near the stone seems reasonable too. Also Quirrell said (in parseltongue):

I have plan to sstop even sschoolmasster, if he appearss before uss.

Appears before us. To me the verb appear evokes images, like in a mirror, more than running into people.

2Subbak10y

And now I feel stupid for not thinking of option 3. While it would be very amusing to have everyone fooled into forgetting that mirrors also reflect things (duh), there are convincing arguments for option 1, the main one being timing.

1Jost10y

Option 2 is implausible, since each person only sees their own CEV in the mirror – as evidenced by Harry not seeing the images of Aberforth and Ariana that confunded!Quirrell (Dumblemort? Quirroldemordore?) saw. (Insofar, the mirror behaves just like in canon.) Or would you assume that Harry (Harriddle?) and Quirrellmort count as one person for the purposes of the mirror? (One person that, in turn, is different from confunded!Quirrellmort?)

0lerjj10y

I think we're meant to take this as everyone being outside the mirror. If anyone is inside, it's real!Dumbledore, but he probably has a method of getting out. That's how I read it, anyway: P.S. how do you quote this? It won't let me copy off of FanFiction.net for some reason.

9jaime200010y

Look at the html source.

2lerjj10y

Yes, that does work. Thanks for that (upvoted now, seemed unfair). This is less convenient, but more general. Cheers.

6MarkusRamikin10y

Just curious, what's wrong with someone who gave advice that 1. was asked for and 2. the asker found useful, getting upvotes?

2lerjj10y

Fair point. I suppose it was that if everyone posted subtle variations on a theme it's a way to vote mine. Or simply copy someone else's answer, write in an "Edit: ninja'd" and hope for accidental votes. Having said that, looking at the HTML is a much more general solution and probably does deserve an up-vote. But the principle was to only give a vote to the first person to answer, because after that help is technically unsolicited (since they can see it's already been given).

4bramflakes10y

Use http://hpmor.com/chapter/109

1lerjj10y

Thanks, upvoted for quick response. The quote is this: This doesn't sound like AD is stuck in the mirror, but I think this rules out QQ being in it. Both would seem to be counter to the story, as it can't end just yet.

2ChristianKl10y

www.hpmor.com allows normal copying.

[-]garabik10y70

Hypothesis: The mirror (or the whole room) connects universes. More specifically, there is only one mirror, stable in the multiverse (quantum, mathematical, magical or whatever) of compatible universes. A compatible universe is such an universe where the mirror exists, i.e. most probably the one that did not branch off before the end of Atlantis (or boltzmanned into existence a moment ago).

Looking into the reflection, your (magical) brain picks the image from a different universe, the one that matches your CEV most closely.

Nothing can hurt the mirror, unle... (read more)

4avichapman10y

+1 for using 'Boltzmann' as a verb.

[-]Unnamed10y70

I am confused. Quirrell's plan to get the Stone out of the Mirror while eluding Dumbledore's traps is: go to the Mirror with Harry, then brainstorm ideas together for how to get the Stone from the Mirror, and then try the riskiest idea that Harry came up with?

[-]fezziwig10y110

His original plan was to set Harry up to retrieve the Stone for a selfless reason, then steal it from him. But Harry figured out the truth, and so that became impossible. I suspect that he had other plans, but that he abandoned them when he realized that Harry understood Dumbledore better than he did.

Having said that, yes, I think he should have spent a few more minutes looking for potential solutions.

0ShardPhoenix10y

Possibly he doesn't have any good ideas for that part but is desperate due to feeling the opportunity is passing.

0Izeinwinter10y

I blame the DADA curse. That, or he did just go even crazier while stargazing. After all, having just one plot in motion to defeat Voldemort would be irresponsible, ... Wait. Yes, that works. Voldemort bluffs Flamel - whoever that actually is - and the stone gets hidden in hogwarts specifically to get Voldemort, who Dumbledore knows wanted the DADA job to walk into the curse.

0kilobug10y

The DADA curse was put by Voldemort itself. Does it affect him ? And can't he lift it ? I wouldn't blame much upon that curse concerning Quirrelmort.

-5Izeinwinter10y

[-]nitrat66510y70

It's a pity we didn't get to see what Harry would see if he looked into the mirror. I half-expected to see the scene where Harry looks into the mirror and sees himself transcend his humanity, becoming an immortal intelligence running on a Matryoska brain, then uses his newfound god-like powers and cognitive abilities to take Hermione's body apart atom by atom and reconstruct her back as a living Hermione, helps her ascend as well, so that the two of them can defeat death, optimize the world, and go on doing all those awesome things Harry once said he wante... (read more)

[-]Ander10y50

Continuing on Izienwinter's reasoning:

Harry and Voldemort sprung the trap, they are now inside the mirror, Dumbledoor is outside.

It is now an AI box experiment, with Dumbledoor as Gatekeeper and Harry as the AI wanting out!

2avichapman10y

And the clock is ticking. If Dumbledoor is aware of the plot to kill hundreds of students, the folks inside the box have some leverage.

0kilobug10y

I wonder how much of that plot to kill hundred of students can actually be foiled/averted by Dumbledore if he were to know, especially if helped by Harry's "creativity" to find solutions.

[-]WalterL10y50

Can the mirror be used to hack the Time Turner restriction? GAH!

Also, reading the letter backwards:

Is how not your face but your coherent extrapolated volition .

9Astazha10y

"I show..."

2WalterL10y

Ah, doh. That certainly makes more sense.

7Jost10y

… which is exactly what the mirror would say, if this were a parody of Eliezer-written Harry Potter-fanfiction. (On the other hand, Eliezer frequently likes to play some pretty absurd things straight (the Comed-Tea induced Quibbler headline, the Yaoi fangirls, …), so … I’m not quite sure what to think. My estimate for P(the ending of HPMoR will be incomprehensible to non-LWers) just went up a bit, but not by much.)

1Unknowns10y

I think the reason this looks like a parody is that it is not an original idea. Eliezer took it from here (http://lesswrong.com/lw/7jd/harry_potter_and_the_methods_of_rationality/4wqy), presumably because he thought it was funny. Still, one could think there is not a huge difference between "heart's desire" and "coherent extrapolated volition" anyway, so it is not that unreasonable.

0gjm10y

We don't know that he took it from there. Note that his comment saying "Great idea!" was posted after the chapter in which he did it so it's clearly joking to some extent. For all we know, Eliezer may have had that plan long before pedanterrific said anything.

1Bugmaster10y

Yeah, and I am kind of surprised that neither Quirrellmort nor Harry thought of reversing the letters. I mean, we are dealing with a magical mirror here. How is this not the first thing they've tried ?

[-]WalterL10y130

I get the feeling from Voldemort's comments and Harry's thoughts that the Letters of False Comprehension have a mind affecting power that prevents you from understanding them. I think the inversion is a joke for the readers.

0Gondolinian10y

I assumed the inversion was because the mirror was somehow reflecting the phrase, or at least that it's some kind of artistic flair meant to suggest so.

2Jost10y

* The letters are in reverse order, but not mirrored. No wonder they didn’t think of that! * It wouldn’t fit the narrative. (Just like it didn’t fit the narrative in canon, so nobody pointed it out there, either.) * Maybe the mirror has some kind of very narrow Confundus charm, that makes a person’s brain unable to process these letters? ;)

8MathMage10y

Well, yes. The False Comprehension Charm is precisely a very narrow Confundus charm that makes a person's brain unable to process these letters--by substituting a convenient, wrong, preprocessed 'answer'.

1The_Duck10y

The inscription is not in the Latin alphabet.

[-]b_sen10y40

Observe that the writing on the back of the Mirror is in runes, not any particular alphabet. The fact that Harry can read anything out of them at all suggests that there is an effect meant to make them 'readable' regardless of what languages / alphabets the reader knows. This effect was presumably placed by someone who knew what the Mirror does and wanted to make sure that knowledge was preserved even if languages changed and the history of the Mirror was lost.

But then why would someone want to obscure the answer by making those runes the Words of False ... (read more)

0b_sen10y

My previous prediction comment is here. Also, the subtle hints at reflective consistency are both funny and hints to Harry about the Mirror's nature.

[-]Gondolinian10y40

It is said, in certain legends that may or may not be fabrications, that this Mirror reflects itself perfectly and therefore its existence is absolutely stable.

I take it "reflect" here means some kind of self-modeling aside from just optical reflection?

[-]linkhyrule510y120

I immediately thought of Eliezer's metaphor of the brain as "the lens that perceives its own flaws", and reflective consistency.

0wwa10y

Perfect mathematical reflection, free of Gödel's incompleteness theorem.

2lfghjkl10y

That's not what reflective consistency means.

5bramflakes10y

CEV is meant to be reflectively consistent.

[-]linkhyrule510y40

I see. "Heart's desire" indeed.

So... Atlantis managed a neutral AI? But see convergence of methods - I'd expect a hypothetical NAI to be considerably harder to build than an FAI.

(Also, nice Duane shout-out.) In what sense is Altantean Magic more like Wizardry than post-Antlantean magic, though? Just the bits about making the Holy Grail as opposed to merely operating it?

(Heh. True Magic.)

Even Riddle would wish to be happy, I think. Or rather, if he knew more, was more capable, and was more the sort of person he wants to be... he would wish to be h... (read more)

5Bugmaster10y

As well as the Mass Effect shout-out. ASSUMING DIRECT CONTROL.

3skeptical_lurker10y

I thought EY said there would be no AI analogy, and yet the mirror clearly is an AI (and it seems more FAI to me than NAI) Well, I suppose he changed his mind. Are MIRI's working conditions pointlessly annoying?

5SilentCal10y

If anyone has the exact wording of the no-AI promise, I'd like to examine it.

6Unknowns10y

Eliezer: Slightly edited the original post to avoid giving away what my readers have finally convinced me is, in fact, an undesirable spoiler. I also hope you didn't mind my removing the mention of FAI, because I feel fairly strongly about not mixing that into the fic. "A fanatic is someone who can't change their mind and won't change the subject"; if we can't shut up about FAI while talking about Harry Potter, we may have a problem. (http://lesswrong.com/lw/2ab/harry_potter_and_the_methods_of_rationality/22cq)

3Vulture10y

Working from memory, I believe that when asked about AI in the story, Eliezer said "they say a crackpot is someone who won't change his mind and won't change the subject -- I endeavor to at least change the subject." Obviously this is non-binding, but it still seems odd to me that he would go ahead and do the whole thing that he did with the mirror.

2CronoDAS10y

He said "Harry will not build an FAI"...

2dxu10y

Source? (Not that I don't believe you; I've just never been able to find where EY says this.)

0CronoDAS10y

I think I heard it from him personally at a meet up...

3linkhyrule510y

It's not an FAI, it hasn't taken over and promptly saved the world yet. Well, I suppose this could all be a very slow plan on its part, but that would be boring, so it's probably magically charged to not do that, in some better-than-English conceptual way. And well, insofar as they're trying to save the world and no major government cares to throw large quantities of public funds at them.

0skeptical_lurker10y

So its not a superhuman FAI. But the Atlanteans were working on superhuman FAI.

2closeness10y

Maybe the AI was asked to make the world safe for wizards and figured it was easier to make an entire new world for them than make safe a Muggle dominated one.

0Richard_Kennaway10y

Reference please? I haven't read much of Diane Duane (assuming that's the Duane).

2linkhyrule510y

So You Want to Be a Wizard is the name of a Duane book, the first in the Young Wizardry series.

0linkhyrule510y

Also, under the assumption that Eliezer reads these threads - usually, the critique is anchored on Harry, but moves on to poking at Draco's little-professor-ness. Though I'm sure there are plenty of idiots who go on about Harry not being eleven, most of the intelligent detractors I've taught to quickly move on. I'm sure that they're anchored by Harry's not-normal-ness, but at least they don't keep pushing that once it's pointed out that Harry is intended to be Voldemort.

2polymathwannabe10y

Am I the only one who thinks it's not realistic that an eleven-year-old in the 1990s hasn't had any dirty thoughts?

9avichapman10y

Some 11 year olds aren't interested in sex yet. Others are forks of an adult Tom Riddle who similarly isn't interested in sex.

3Transfuturist10y

Harry's a late bloomer, and he doesn't have any sexual figures around him to induce fantasy.

2DanielLC10y

He did read all of the books he's not supposed to.

0fubarobfusco10y

I'm not as smart as fictional Harry, but I knew at a younger age that books about sex (e.g. sex-ed texts intended for an adolescent audience, when I was several years from it) were books that some adults would prefer I not get into.

[-]Tenoke10y30

The thought of making a better horcrux, of not being content with the spell I had already learned... this thought did not come to me until I had grasped the stupidity of ordinary people, and realised which follies of theirs I had imitated.

This apparently happened significantly later in his life. However

"Nine years and four months after that night, a wandering adventurer named Quirinus Quirrell won past the protections guarding one of my earliest horcruxes.

Doesn't this suggest that Quirrell stumbled upon a horcrux v1, given that it was one of t... (read more)

0higurashimerlin10y

The one Quirrel found was probably a version 2 horcrux. After all you don't hide the version 1 horcruxes because people need to touch them to be overwritten. Tom thought he had fixed that with the version two and started hiding them.

6Tenoke10y

The text suggests that Riddle was stupider at a younger age, which is when he made v1 horcruxes, and used story-like hidding places like those mentioned above. Then later on when he was porbably at least 'twice [harry's] age' he grew wizer, made the horcrux v2, and started hiding them well. Then he dies, and finds out that his only hope is the horcruxes from his youth, which weren't hidden well, and it is suggested that Quirrel found one of those, so likely a v1 horcrux. At any rate, even if we just focus on the 'one of my earliest horcruxes' part, that still heavily implies a v1 horcrux.

[-]jimrandomh10y30

Chapter 89 (spoken as prophecy, heard by Quirrell):

“He is here. The one who will tear apart the very stars in heaven. He is here. He is the end of the world."

Chapter 109:

Merlin left written instructions that the Mirror did not need to be sealed away, despite it having certain powers that might normally cause one to worry. His exact wording was that, given how painstakingly the Mirror had been crafted to not destroy the world, it would be easier to destroy the world using a lump of cheese.

I would say this implies that Quirrell ought to have triggered a safeguard on the Mirror, without Dumbledore needing to have installed it.

[-]Ander10y30

It looks like AI will make an appearance in hpmor! I had thought that Eliezer was simply going to go with an anti-death plot for the climax and not include AI, but here we are with the mirror. Looking forward to seeing how it plays out.

5gjm10y

Sufficiently advanced magic is indistinguishable from technology.

[-]lerjj10y20

I don't really have much to say after reading that. My thought process is pretty much summed up like this: "But Dumbledore can't beat Voldemort!" "Maybe he can. In canon he can (kinda), and even in the last few chapters QQ has given him some grudging respect," "Seriously? Voldemort was winning the Wizarding War, whilst holding back!" "Dumbledore might have been as well. Anyway, we've only got Voldemort's word on this. Also, check to see what parts of ch 108 were in Parseltongue. Maybe there's a better reason for why Volde... (read more)

[-]Izeinwinter10y210

He's standing in a indestructible oracle. That he knows how to use, and Tom doesn't. That is the most awesomely rigged battleground possible.

Re: The words on the mirror. In-universe, "CEV" is likely a translation from the atlanean - any reader will get a mirrored phrase which is the closest mapping to what it does which exists in their language or something like it.

3lerjj10y

I find the assumption that Dumbledore is in the mirror and can use it suspect. I fully expect him to either (a) not be in the mirror, but actually behind it/other side of room. or (b) to simply walk out at the start of the next chapter. So no, I don't expect an epic battle next chapter. However, I don't see a way out of one... I notice that I am confused. (Prediction: Dumbledore comes out of the mirror, followed by several more Dumbledore's. Or maybe multiple ancient Dark Wizards and Light Lords... would explain the Map's confusion. This actually could lead to an epic battle.)

4Ben Pace10y

I expect that Dumbledore and Quirrrell cannot affect each other whilst Dumbledore is in the mirror, and so they will negotiate.

3Izeinwinter10y

"Baba Yaga and her 52 apprentices"? That's possible, but I'm not actually sure how this can become a battle because the obvious move is for Riddle to "bombarda" his own skull. I'm thinking we are going to get some more talking. And it is pretty likely we are about to have explained to us how he already lost... Wait. Are we at all sure the Tom's are still outside the mirror? If the plan was to trap Voldemort in the mirror, how do we know that didn't already happen, and this is years later when they finally finished tracking down the horcruxes? Because the best mirror-plane prison would be one with no passage of time in it. This also fits the prophecy, because in this case, Harry did defeat him, by being willing to go down with him. Which is a power he knows not.

0gwillen10y

Hmm, "Both Toms are trapped in the mirror, Myst-style" would explain a bit of my confusion, to wit: how is it that the first invocation of the mirror was only visible to Voldemort, but the trap-invocation seems visible to both Riddles, even though Harry is under the True Cloak and thus not visible to the mirror? (On the other hand, if that's true, how did the trap get sprung on him?)

0Transfuturist10y

The trap-invocation is visible to both because they are in Dumbledore's invocation of the mirror now, and Dumbledore is the one looking in.

0linkhyrule510y

Right, but the Mirror (in theory) has no power over anything not reflected in it, and Harry's still invisible.

0Transfuturist10y

It might have inverted the whole room, with Harry being caught up in it. The Cloak allegedly only evades the Mirror, not challenging its perfect reflection.

3Desrtopa10y

It might have been possible for Quirrellmort to win the war in a few days, but I think the implication is supposed to be that he could do so by superior inventiveness and planning ability, rather than by superior dueling power. Indeed, going by his demonstrated methods, he might have been able to defeat Dumbledore in the war in spite of dramatically less dueling power. Minerva has apparently survived skirmishes with Voldemort where Moody or Dumbledore were at her side on different occasions, and if Voldemort could have overcome his opponents in those encounters with no risk to himself, I think he'd have had a hard time rationalizing passing up the chance.

1WalterL10y

It was also to Voldemort's advantage to keep the battle ratcheting slowly up as long as possible, to get Flamel to give Dumbledore ever more lore, which David Munroe could get access to.

0kilobug10y

"Dumbledore can't beat Voldemort" to me means that he can't beat the horcrux network, not that he can't win against Voldemort in a duel. But that would be winning a duel, not winning the war.

[-]bramflakes10y10

Wait a minute, aren't all human CEVs supposed to converge to roughly the same thing? (tell me if I've catastrophically misunderstood or misremembered the concept, it's been a while since I read the sequences)

6Alejandro110y

In all details, certainly not; Dumbledore's CEV might well include reuniting with his family, which won't be a part of others' CEV. In broad things like ethics and politics, it is hoped that different people's CEVs aren't too far apart (thanks to human values originating in our distant evolutionary history, which is shared by all present-day humans) but there is no proof, and many would dispute it. At least that is my understanding.

2Luke_A_Somers10y

Two peoples' individual CEV are expected to be widely divergent. However, if one applies CEV to large numbers of people in aggregate, there are expected to be some things which survive the reconciliation process - things they can all get behind, or would if they were smarter. Each of these is probably really obvious like 'death and brain damage really suck' or really meta like a good system for resolving conflicts between conflicting sets of individual values, possibly including ways of arranging matters so that the conflicts do not arise in the first place.

[-]UjjwalRajput9y00

Does anyone remember an event from the whole book when Harry thought about Turning Time while already being in past.

0gjm9y

Could you be more specific? There are quite a lot of places where Harry thinks about the 6-hour restriction, which is what limits use a of Time-Turner after already having used one. There are places where it's an important plot element. Are you trying to find a particular scene you only remember bits of?

[-][anonymous]10y00

OK, that answers a bunch of questions. Magic is an unfriendly tool AI, Atlantis was destroyed by misusing it, and the mirror is an incomplete but stable (reflectively consistent, haha) friendly AI. That makes perfect sense and many people have suggested similar theories, but didn't Eliezer promise not to do that?

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