All of Eponymuse's Comments + Replies

Harry Potter and the Methods of Rationality discussion thread, part 15, chapter 84

I downvoted the previous post because it was a needlessly complicated, poorly justified plan. Crucially, there was little indication of why Voldemort would want to pretend to lose, when he was already winning the war. By contrast, your more recent post is a good analysis of the new insight into Voldemort's history and motivations provided by the latest chapter.

Harry Potter and the Methods of Rationality discussion thread, part 14, chapter 82

I'm not saying I think Narcissa is alive, but...

There’s no obvious reason not to return her after he thought Voldemort was gone

Except that Narcissa could then testify in front of the Wizengamot that Dumbledore kidnapped her.

or at least to let Lucius know what happened in case she’s alive and didn’t want to return

Dumbledore believes Voldemort will return. This would limit his ability to threaten Death Eaters in the next war.

4bogdanb9yPoint. I forgot he knew about the Horcruxes since basically the beginning.
Harry Potter and the Methods of Rationality discussion thread, part 14, chapter 82

I would much prefer to have them released all at once. I could read them and re-read them at my own pace. There would still be plenty to discuss. The cliff-hangers mean that I currently think about each update more than is productive. It would be nice if the disruptive effect they have on the rest of my life was more localized.

Mostly, though, I'm happy to read it whenever EY gets around to posting it.

2Paulovsk9yI think exactly like that. I vote up to have them released all at once.
Harry Potter and the Methods of Rationality discussion thread, part 13, chapter 81

Sorry, apparently I'm illiterate.

Also, I guess "siblings getting killed" isn't much of a pattern. Given that people were getting killed in the war, and that people have siblings, you can count the people getting killed as siblings.

Harry Potter and the Methods of Rationality discussion thread, part 13, chapter 81

It's also difficult to see why Voldemort would want to pretend to die at Godric's Hollow. He was winning the war. Why pretend to lose, throw away what he had built up to then, and try an entirely different approach to gaining power? I think the more obvious explanation for the burnt body is that whatever ritual magic protected Harry was very destructive to Voldemort. I think it is clear that some ritual magic is involved here; how else can we explain the danger of Harry's and Quirrell's magic interacting? And the violence of their magics' interaction in Azkaban makes it plausible that if Voldemort were to cast a killing curse directly at Harry, he might end up as a burnt corpse.

0[anonymous]9yTentative explanation: he was hedging his bets. If it's a trap, to walk into it would be stupid. If it's genuine, to ignore a warning like that would be stupid, too. He acted in a way that accommodated either possibility. I think the ritual he performed that night was copying himself into Harry (note to self: this may or may not be the same thing as horcruxing), and the resonance between their magics is a side effect of that. As to which explanation is more obvious, well, I don't think an argument from obviousness is valid in the face of a genuine disagreement, so I withdraw mine. It's reasonable, though.
Harry Potter and the Methods of Rationality discussion thread, part 13, chapter 81

Perhaps its not such a strange thing to say if you don't think Mr. Potter knows about the prophecy, and are trying to correct his insubordination. In the following chapters, Dumbledore doesn't act as though he has decided Harry is unsuitable as a hero. Rather than trying to replace him, Dumbledore begins to confide in him.

Does Nornagest's explanation of Dumbledore's relationship with story-book reasoning affect your previous analysis? If you agree that Dumbledore feigns a story-book persona, rather than taking story-book logic seriously, then doesn't it se... (read more)

Harry Potter and the Methods of Rationality discussion thread, part 13, chapter 81

You are right, those are both possibilities. Though, one of them has been explicitly presented by the author, and endorsed by Harry. I don't think we have much reason to doubt the canonical interpretation.

"SO THAT'S HOW THE COMED-TEA WORKS! Of course! The spell doesn't force funny events to happen, it just makes you feel an impulse to drink right before funny things are going to happen anyway! I'm such a fool, I should have realized when I felt the impulse to drink the Comed-Tea before Dumbledore's second speech, didn't drink it, and then choked on

... (read more)
Harry Potter and the Methods of Rationality discussion thread, part 13, chapter 81

Harry could still get a false negative. Remember, Harry will feel the impulse to offer a drink to Alice if and only if if Alice is about to be surprised. So not feeling an impulse to offer her a drink would indicate that either that Alice would not be surprised that Voldemort is alive, or that Harry will not actually end up telling her.

1FAWS9yAgain, we don't know that. The soda working in two steps as you seem to suggest (detecting future surprise, then determining whether that surprise is sufficient to cause soda spitting when drunk at the right time) is consistent with what we know about the soda. But that's not the only possibility consistent with what we know. The soda could also work in a single step and detect whether soda drunk at various points would be spit, without directly detecting surprise at all.
Harry Potter and the Methods of Rationality discussion thread, part 13, chapter 81

If, for example, Harry wishes to test whether or not someone knows that Voldemort is alive, he could see if he has the Impulse to give that person a drink, all while thinking about saying that "The Dark Lord is still alive". If he gets the Impulse, they don't know. If he doesn't, then they already know/has been suspecting that he's been alive.

Unless he actually followed through with saying that Voldemort is still alive, this wouldn't be enough.

0[anonymous]9yWhat if he actually planned on going through with saying "The Dark Lord is still alive", but got Silencio'd by an invisible time-turned Harry he wasn't aware of right as he's about to say it? It'd be obvious, but at least he wouldn't actually release the secret?
0FAWS9yWe don't know that, committing to saying Vldemort is alive conditional on actually giving them a can might suffice.
Harry Potter and the Methods of Rationality discussion thread, part 13, chapter 81

In the aftermath of the prophecy, his manipulation of Snape and Lily netted him a defeated Dark Lord, a double agent and powerful ally, and a newly horcruxed hero. If the prophecy hadn't occurred, he'd instead have... a bouncing baby boy. It's hard to see what he hoped to accomplish by driving Snape and Lily apart if he didn't intend to prod Voldemort into attacking the Potters.

One possibility is that he didn't intentionally drive Snape and Lily apart. I don't think there's enough evidence of that to overcome the prior probability that Trelawney's proph... (read more)

2[anonymous]9yAh. See, my prior probability that Trelawney's prophecy was genuine is not very high. * Luna [http://hpmor.com/chapter/7] * The seer [http://hpmor.com/chapter/26] in the Weasley twins' story * The seer [http://hpmor.com/chapter/38] in the Quibbler story * Millicent [http://hpmor.com/chapter/72] * Millicent's source [http://hpmor.com/chapter/77], presumably Rianne This story has an epidemic of false prophecy. This looks to me like it's intended to prime the reader to accept that an apparently true prophecy is actually false. I also think this [http://lesswrong.com/lw/b5s/harry_potter_and_the_methods_of_rationality/65fu] is a consideration, but that appears to be a minority view. I'm expecting a false prophecy, and I'm looking for a reason for it to have occurred and apparently been fulfilled despite its falsity. I think Dumbledore expected the story to play out as it did in the novels. He would get a hero who was bred with the heroic qualities of his parents, bullheaded but pure of heart. Snape, who in HPMoR is terrible at riddles [http://hpmor.com/chapter/76], would fail to solve this one, and his guilt at causing Lily's death would cement his status as a lifelong soldier of the light. Lily would die a martyr, and her sacrifice [http://harrypotter.wikia.com/wiki/Sacrificial_protection] would ensure Voldemort's defeat. From canon: This is a complex plot that hinges on storybook logic, but that's not [http://hpmor.com/chapter/35] out of character for Dumbledore. (Yes, it's Quirrell saying it, but remember that he was right [http://lesswrong.com/lw/3rb/harry_potter_and_the_methods_of_rationality/3m4l].) The plot is not too complex to be Dumbledore's, but it is too complex to succeed. That's why it didn't. Snape is no longer Dumbledore's. Instead of canon!Harry, he got HJPEV. Harry's mother attacked Voldemort, so her protection doesn't exist; Quirrell can pass the wards around his house at will. And although it failed, it has the outward appearance of havin
Harry Potter and the Methods of Rationality discussion thread, part 11

You're right, I misremembered. Still, I think there is a lot to suggest that interacting directly with one's time-clones (as opposed to waiting with one's eyes closed while a clone drops off a message, for example), particularly in battle, is a bad idea. You would never observe a future-you doing something ineffective in combat---failing to dodge or block, or casting an ineffective spell, for example---since, after observing that mistake, you would be prepared for it in the future. So the only consistent possibilities involve losing or running away before ... (read more)

Harry Potter and the Methods of Rationality discussion thread, part 11

He has never interacted directly with himself in a way that involves seeing a copy of himself, or coordinating actions in real-time, as would be the case in a battle. Harry has so far always heeded Professor McGonnagal's advice, and looked the other way when his time clones are around. Though, as pedanterrific points out, I have overstated the severity of McGonnagal's warning.

Harry Potter and the Methods of Rationality discussion thread, part 13, chapter 81

Seems unlikely that the original prophecy was caused by Dumbledore, at least by the method of the magical clock. As in canon, Trelawney seems to have made the prophecy during a job interview, presumably before she was regularly sleeping with the clock. I expect that if Dumbledore wanted her to make a false prophecy at a specific time, something like an Imperius folled by Obliviation would be more expedient. Furthermore, we have seen Trelawney spontaneously prophecy in the dining hall; this prophecy at least appeared unplanned by Dumbledore.

0[anonymous]9yRegardless of what the clock is for, it didn't play a part in the first prophecy, since Trelawney didn't receive it until after she was hired. And it's less likely that there are two ways of forcing someone to speak a prophecy than only one. The obvious explanation for the clock is that it's a listening device. The clock is evidence against Dumbledore being the source of the prophecies. The issue of the second prophecy is trickier. For a prophecy to be 'accidentally' overheard would be history repeating itself, if Dumbledore caused it. That would also be consistent behavior for a liar who tries to trick people into believing in destiny, as he did when he told Harry [http://hpmor.com/chapter/17] that his father's cloak had found its own way to its destined wearer. But it certainly looked like Dumbledore was surprised that morning, so I don't know. I think the weight of evidence is still on Dumbledore. For the reasons I've given in this thread, and also this: In the aftermath of the prophecy, his manipulation of Snape and Lily netted him a defeated Dark Lord, a double agent and powerful ally, and a newly horcruxed hero. If the prophecy hadn't occurred, he'd instead have... a bouncing baby boy. It's hard to see what he hoped to accomplish by driving Snape and Lily apart if he didn't intend to prod Voldemort into attacking the Potters. His plot has a prophecy-shaped hole in it. But I can't account for that damned clock, which means I've gone wrong somewhere. Ugh. I hope someone else gets interested in this question soon. I could use the help.
Harry Potter and the Methods of Rationality discussion thread, part 11

Sure, though my impression is that people don't think graph isomorphism actually is in P. And integer factorization turned out to be a problem for Harry. But you're right, we can actually just simulate a nondeterministic Turing machine this way: every time you have a choice for which state to visit next, just listen as future you tells you which ones not to visit.

Harry Potter and the Methods of Rationality discussion thread, part 11

Sorry, I'm really not following your pie argument. Harry would learn about the pies in the near future; since it is his style, he would think about throwing them to frighten the bullies. So, his observation of Harry+1 throwing the pies is not necessary for him to think to throw pies anyway.

What do you mean by "they don't recurse"? Surely the fact that this procedure results in fast graph isomorphism testing shows that it is not a particularly "stable" solution? Or, do fast integer factorization by writing down the first digit for the le... (read more)

1JoshuaZ9yNote that both graph isomorphism and integer factorization are problems that may well lie in P, so these aren't great examples. Traveling salesman is a bit better.
0Logos019yHarry+0's actions or non-actions were radically transformed by the act of Harry+1's throwing the pies. The solutionspace for Harry+0's problems were altered by the actions of Harry+1. From this we must derive the answer that iteration can alter outcomes. However, from the factoring of primes we see that the TT resists allowing iteration to recurse beyond the actual number of iterations. Where number-of-iterations = i, where i < 6, then Harry+0..i can perform as many recursive alterations of his own solution-seeking as can be achieved without exceeding the value of i.
Harry Potter and the Methods of Rationality discussion thread, part 13, chapter 81

I hope you write the ending you want, rather than playing games to see which ending we will earn.

1thomblake9yNot to worry, I'd expect that both endings will be written, and the game will just determine which one gets labelled "True Ending" in big, friendly letters.
Harry Potter and the Methods of Rationality discussion thread, part 11

that doesn't follow. Where would Harry have gotten the pies if not from Harry+1?

He got them from the breakfast table. Where did he get the idea to get them? Well, he would have seen the pies later on anyway. Just like he would have learned about time turners later on in the day anyway, but a more stable scenario was obtained by learning about them earlier.

The recursion is non-iterative beyond the number of loops actually manifested, however.

I'm not quite sure how to parse this. If you would think about an idea at time T, but don't because future you... (read more)

0Logos019yNo. That's where Harry+1 got them. Harry did not. Six turnings of the Turner at T=0 results in the same 1-hour segment being looped into 6 times. This allows six iterations -- but those iterations do not recurse beyond the actual number of loops. < is that you are gaining information as a result of some work, but that work is never performed. That doesn't follow. How do you figure?
Harry Potter and the Methods of Rationality discussion thread, part 13, chapter 81

There is one offhand remark, vengeance, and a practical cold-heartedness favoring Bones. "Why not Bones?" is only a little better than no argument at all.

Also there is the fact (mentioned by someone else, sorry I forget who) that Narcissa's sister, Bellatrix, murdered Bones' brother. Edit: I am an idiot, you already mentioned this.

Bringing in Aberforth is a really interesting idea. Now that I think about it, even given the wizarding wars, it is remarkable that so many siblings have died or nearly died:

  • Albus/Aberforth

  • Bellatrix/Narcissa

  • Bon

... (read more)
4buybuydandavis9yAlso, Bones is the one who speaks up to stop Dumbledore from "confessing" to killing Narcissa. I think it's Bones. Too many coincidences otherwise.
2pedanterrific9yIt was meee [http://lesswrong.com/lw/axe/harry_potter_and_the_methods_of_rationality/637j]. Also there's the Bellatrix idea [http://lesswrong.com/lw/axe/harry_potter_and_the_methods_of_rationality/62m4]. /shameless self-promotion
Harry Potter and the Methods of Rationality discussion thread, part 13, chapter 81

I think Lucius may have been playing very high speed chess when he picked the amount. The point isnt to have Harry in debt to him, the point is to afford ex-deatheaters loyal to Lucius the oppertunity to trade in a blood debt to Harry for a monetary one to him.

I don't think so. It's clear from his reaction that he did not want Harry to accept the trade:

It was clear that Lucius Malfoy had not been expecting that reply.

And later:

"I withdraw my offer!" shouted the Lord of Malfoy. "I will not accept the debt to House Potter in payment,

... (read more)
Harry Potter and the Methods of Rationality discussion thread, part 13, chapter 81

I don't get how a cunning Slytherin like him can discard such an advantage for pure vengeance over an "attempt" which didn't do any real harm.

On the contrary:

And Draco was getting angry again. "Dumbledore killed Mother, it's not enough to just say it's sad! I don't understand what you think you have to do, but the Malfoys have to take revenge!" Not avenging the deaths of family went beyond weakness, beyond dishonor, you might as well not exist.

Lucius never meant for Harry to accept the monetary bargain. This is clear from his reaction. He wanted his revenge, and Harry was interfering.

Harry Potter and the Methods of Rationality discussion thread, part 13, chapter 81

I completely agree. Recall also Draco's speech about muggles scratching in the dirt, and his reaction to Harry's estimate of the lunar program budget. It's not just wizards not paying attention to relative values of gold and silver in the muggle world---for the most part, the possibility that there could be a substantial amount of either in the muggle world doesn't occur to them. Now you might expect muggleborns to know better, even after making allowances for the fact that they enter the wizarding world at age 11. On the other hand, if a muggleborn is cle... (read more)

1Normal_Anomaly9yAll good points, but I don't think Harry is planning on "calling atttention to the fact that the muggles are ripe for exploitation". He's presumably planning to make the money without anyone except one or two adults he needs for transportation/permission/whatever knowing how he did it.

I would actually suspect parents of a half blood (is there a name for this?) would be the weak link, rather than muggle-born children.

You've got people who have lived their whole lives as muggles, then suddenly they fall in love and get married and find out their spouse is a wizard. They've spent ~20 years in the muggle world and probably have a career of their own. No way they don't ask their spouse to spend a couple hours and let them both live like kings for the rest of their lives. And if they don't even get that much information about their other's life, that's some seriously messed up power dynamics in that household.

Also, as Harry himself speculates, muggleborns, like his mother, probably tend to fall into the habit of not thinking of muggles as Real People anymore, because it's too emotionally taxing, and they're living in a different world. They may stop concerning themselves with the muggle world much by the time they're grown up. The muggle raised wizards in the original canon certainly seemed to.

Harry Potter and the Methods of Rationality discussion thread, part 11

I see. So I guess there is some benefit gained from this, but it is very minor. It seems to me that the simplest rule that explains why Harry's integer factorization is not okay, but, for example, the "silver on the tree" password from the end of TSPE is okay, is the following: if you would gain information at time T, and send information from time T to any time S < T, then it must be the case that you would have gained that same information even if you hadn't learned it at time S.

Now consider your "keying" scenario. We have clones ... (read more)

0Logos019ythat doesn't follow. Where would Harry have gotten the pies if not from Harry+1? The recursion is non-iterative beyond the number of loops actually manifested, however. Each individual only adjusts the one previous, and only in immediately non-iterative manners. "Nope. Nope. Nope. Maybe. Nope. Nope. Maybe." That lets you prune out failed items but doesn't recurse back to an instantaneous success.
Harry Potter and the Methods of Rationality discussion thread, part 11

I'm not sure I understand what you mean by "keying." Could you elaborate, and explain how you end up with a scenario that is more stable from "Time's perspective" than, say, clone #5 just summarizing all the ideas at the beginning of the hour? The scenarios I can come up with seem to involve information magically appearing (which the universe doesn't seem to like, as in Harry's integer factorization algorithm), or fail to provide a benefit over just thinking on one's own for six hours.

0Logos019yclone #5 summarizing means clones 1-4 never actually have the ideas, but cannot contribute any further to the solution-space beyond claiming they had those ideas. This doesn't create an additive effort to deriving a desired answer from the available solutions-space of your problem. By "keying" I mean something that informs other iterations of the idea you're currently having and its invalidity without telling them the idea. "The thought I had at 5:14 -- it won't work. Move on." This allows all six iterations to contribute towards deriving a viable answer without running into loops which require recursion to reach a stable state, which seems to be the kinds of loops that the Turners don't allow. (Helping a previous version's okay as long as they don't know where the help is coming from; but factoring integers instantly is not.)
Harry Potter and the Methods of Rationality discussion thread, part 11

Good point, though I don't think this would ever be useful. In the unlikely scenario that Time-Traveling Tom has a problem amenable to a straightforward, parallelized algorithm which requires six Tom-hours while Tom needs the solution within two hours, he may as well just go back six hours, "thread" his thoughts, not bother with any communication.

0Logos019yWell... there are other such scenarios. Spend 6 hours brainstorming on an idea. Only mention FAILED ideas aloud amongst your fellow Turn-clones. Do so in a manner that requires "keying" to what specifically you're thinking about at the time. (Such as minutes-into-the-hour). After 6 iterations, acquire profit. This has the added advantage that it follows the "DO NOT MESS WITH TIME" restriction of following by rote.
Harry Potter and the Methods of Rationality discussion thread, part 11

Dumbledore doesn't give a straight answer when Harry asks if more than one time turner can be used to get more than 30 hours.

There was another slight pause, during which Harry went on smiling. He was a little apprehensive, actually a lot apprehensive, but once it had become clear that Dumbledore was deliberately messing with him, something within him absolutely refused to sit and take it like a defenseless lump.

"I'm afraid Time doesn't like being stretched out too much," said Dumbledore after the slight pause, "and yet we ourselves seem to

... (read more)
2DanArmak9yThat's just the usual limit on information not traveling more than six wall-clock hours back in time, total. It doesn't say or imply that you can't loop yourself more than six times within a small stretch of wall-time.
Harry Potter and the Methods of Rationality discussion thread, part 11

Consistency is important. We see this in full force in the Azkaban arc.

To get 6 of yourself, starting at noon, you wouldn't go back to 11, then "together" go back to 10. You have already created a paradox because the original 11 o'clock you was supposed to wait until noon and then go back in time. Instead, at 11, you would walk into a room with 5 other copies of you waiting, and then at noon, you and 4 of those copies would go back in time to 11.

Harry Potter and the Methods of Rationality discussion thread, part 11

Some of them will magically disappear every hour until only one remains, but imagine the firepower!

They wouldn't disappear. They would, after a period, go back in time in order to become one of the other people in the battle.

Using a time turner to make clones in battle is a very, very dangerous idea. Harry has been warned, strenuously, by Professor McGonnagal that he should not directly interact with himself, and we have an anecdote about an auror/criminal pair that went insane because they abused time turners. I imagine that one of the more stable time... (read more)

0TobyBartels9yMost of the replies to this comment no longer appear on the main page of the topic, no matter how many buttons I push.
0TobyBartels9yI forget if we're discussing MoR or canon, but either way I object. In canon, my objection is pedantic: it's Hermione who was warned, and she only later passed on that warning to Harry. In MoR, Harry has interacted with himself, a few times, and while they didn't all go well, there were no disasters.
4Logos019yThere are ways to compute problems such that you do not know the information you are computing. Homomorphic Encryption for example.
4DanArmak9yI realize that. For other observers' practical purposes, they would disappear. Meh, she worries about that kind of thing too much.
Counterfactual Mugging

Ah. But under mild assumptions about how Omega's simulation works, I can expect that with some probability p bounded away from zero, I am in a simulation. So with probability at least p, there is another universe I care about, and I can increase utility there.

So, I guess I do pay $100, but only because my utility function values the utility of others. I remain unconvinced that paying is winning for someone with a different utility function.

Counterfactual Mugging

The only mechanisms I know of by which Omega can accurately predict me without introducing paradoxes is by running something like a simulation, as others have suggested. But I really, truly, only care about the universe I happen to know about, and for the life of me, I can't figure out why I should care about any other. So even if the universe I perceive really is just simulated so that Omega can figure out what I would do in this situation, I don't understand why I should care about "my" utility in some other universe. So, two box, keep my $100.

Edit: I should add that my not caring about other universes is conditional on my having no reason to believe they exist.

1Eponymuse9yAh. But under mild assumptions about how Omega's simulation works, I can expect that with some probability p bounded away from zero, I am in a simulation. So with probability at least p, there is another universe I care about, and I can increase utility there. So, I guess I do pay $100, but only because my utility function values the utility of others. I remain unconvinced that paying is winning for someone with a different utility function.
Harry Potter and the Methods of Rationality discussion thread, part 11

I find it very unlikely that Bella is in contact with anyone except the healer. Why would Quirrell want her running around and discussing the escape with people? It's also unlikely that she remembers any part of the escape from Azkaban at all, including Harry's role. Remember that she was Obliviated.

3buybuydandavis9yWhy? So that there is a convincing witness that Harry is Voldemort, as I said. I've stated elsewhere a number of reasons why he would want some people to believe that. That's not sufficient evidence that she was in fact obliviated. I can wave a stick and say obliviate too, and no one will be obliviated. Surely Quirrell could manage that as well.
1buybuydandavis9yWhy? So that there is a convincing witness that Harry is Voldemort, as I said. I've stated elsewhere a number of reasons why he would want some people to believe that. That's not sufficient evidence that she was in fact obliviated. I can wave a stick and say obliviate too, and no one will be obliviated. Surely Quirrell could manage that as well.
Harry Potter and the Methods of Rationality discussion thread, part 11

These are good observations. However, I think you are inferring plot points from what is merely literary technique. H&C using the same disguise is well explained by EY intending us to identify Hermione's manipulator with Zabini's. Similarly, the many attempts/Hermione's exhaustion are well explained if EY wants to make it clear what the nature of the attack is without spelling it out explicitly.

Harry Potter and the Methods of Rationality discussion thread, part 11

The inefficiency of H&C's attack against Hermione's mind is not evidence of a "simple mistake" on his/her part, but rather exceptional cleverness. Note that this attack has replaced something that would be detected (Legilimency) with something that cannot be (Obliviation). I myself take this as further evidence that H&C is Quirrell.

Were there other mistakes you had in mind?

2Locke9yUsing obliviation wasn't a bad move, but H&C used it poorly. More specifically, he used exactly the same disguise he was running around in when manipulating Zabini, when a great manipulator would certainly change their appearance to suit the situation. Not to mention the entirety of his conversation with Hermione strikes me as, well, clumsy. Professor Quirrell can convince most people of most things without multiple trials, and even if he modeled Hermione as putting on a show of goodness H&C's methods are not the ideal way to convince someone like that. Quirrell does not normally have the luxury of obliviation, yet I have no doubt he could have convinced Hermione entirely without it. If he did use it, it would not be enough that she would start to feel tired. He's too good.
Harry Potter and the Methods of Rationality discussion thread, part 11

It seems unlikely that the good Defense Professor would have orchestrated a plan which is entirely dependent for it's success on Lucius failing to take advantage of the situation - unless putting Harry in Lucius's debt was his goal.

Assuming Quirrell is Voldemort, he presumably had years of access to Lucius' mind (if he regularly required Lucius to drop Occlumency barriers). At the very least, we can assume he has an excellent mental model of how Lucius behaves. The plot therefore doesn't seem like too great of risk for Quirrell, particularly when we co... (read more)