1. The obsession with precise times in the last few chapters, the prominence of time-turners in the plot in general, and Harry's vow to revive Hermione all indicate use of time-turners in the final arc.
  2. EY has involved many of his favorite ideas and themes (especially from the sequences) into HPMOR already. Timeless Decision Theory is without a doubt among his most prominent interests.
  3. Harry has already gained two superpowers (super-patronus and partial transfiguration) by virtue of, well, being a proponent of EY's favorite themes essentially. Why not a third?
  4. One specific concrete use would be to coordinate an indefinite number of selves in the way that Harry failed to during the prime-factoring experiment in the early chapters. Why did that experiment fail? Not because time is impossible to mess with, but because one of the Harry's messed up. But since then, Harry has been pushing the bounds of paradox. If he could firmly pre-commit to follow through on a course of action (perhaps with an unbreakable oath?) he could have an indefinite number of Harry's coordinate on some action. There are many ways this could be useful.
Comments? Criticism?


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20 comments, sorted by Click to highlight new comments since: Today at 6:42 AM

Better suited for the HPMOR or at least the Open Thread.

I searched discussion for HPMOR before I posted this to make sure it was an appropriate topic, and lo-and-behold tons of HPMOR stuff comes up. If there is a policy against this, make it explicit.

Tenoke means that you should have posted it as a top-level comment in this thread, the last HPMOR-specific discussion thread, or the latest open thread if you wanted to make sure it got seen. There's also a HPMOR subreddit on reddit that is active.

There one ark left. that ark is going to be about Harry trying to revive Hermoione and in the process either coming close to ending the world or actually ending it.

I could imagine that using a unbreakable vow to look in that he's doing everything in his power to safe Hermoine sets that project in motion.

Perhaps the unbreakable vow becomes the ultimate pre-commitment...

the unbreakable vow is completely broken....

Has TDT been mentioned in HPMOR in the story before?

Complete the Pattern of Eliezer's Mosst Important Beliefs: Reductionism, Transhumanism, ... TDT?

It doesn't seem quite right.

I don't expect a huge explication necessarily: Harry will just realize that a certain degree of self-consistency and pre-commitment will let him resolve paradoxes that ordinarily result from time travel.

TDT is a major focus of his academic work. And AI is already covered (Harry's ballooning capabilties and pseudo-superpowers once introduced to magic represent the nigh-magical capacities a FOOMING AI should have) so TDT could come next.

My first question was for literary reasons - I don't expect TDT to be involved in any significant resolution unless it has been at least mentioned in the text previously, prefereably with some explanation.

I'm not convinced of the analogy to AI-FOOM. Harry's capabilities and pseudo superpowers are the result of intelligence and rationality applied to magic, not of recursive intelligence amplification giving far greater levels of intelligence. It has been explicitly said somewhere that AI will not be involved in the resolution, so I'm not particularly worried about that.

Additionally, since this Harry lacks Eliezer's interest and previous work on advanced decision theory (TDT was created because he needed a reflectively consistent decision theory), and I don't see any reason for Haryy to have developed TDT. I suppose it could be treated like the hedonic treadmill and feeding your inner pigeon work, but that seems unlikely.

Transhumanism and Reductionism don't seem to be in the same class as TDT to me, so even if your proposed schema about how Harry gains superpowers was right, I don't think TDT would be next, or really in the running. TDT seems much more like a technical achievement than a philosophical viewpoint to me.

Harry has already relied on timeless physics to invent partial transfiguration, and his decision theory since the first chapters has included timeless elements too. It's not too big a step.

Harry relates to AI because he is a disruptively intelligent force using his superior intelligence in ways totally unexpected and supposedly impossible to the existing wizarding populace. Nothing to do with feedback loops, more the "general relativity from a video of an apple falling" stuff. And his unpredictability terrifies even Quirrell, who he has clearly surpassed on some dimensions if not others.

I don't think TDT will be mentioned explicitly, but Harry's use of time-turners has been building in complexity. I think the time is ripe for him to break the supposed rules, just like he broke the rules of Patronuses and transfiguration. And it seems like Timeless decision making first perfectly with Time Turners.

It has been explicitly said somewhere that AI will not be involved in the resolution, so I'm not particularly worried about that.


It has been explicitly said somewhere that AI will not be involved in the resolution, so I'm not particularly worried about that.

Interesting. A superintelligence keyed to wearers of the genetic marker was my best guess. Where was that said?

Actually, I misspoke - IIRC, it was about FOOM, not superitelligence ; that Harry won't build an FAI to solve the story, and that the story is not about AI, not that it will have no part in it. I don't recall where exactly, but it was associated with the saying about "a fanatic is someone who only cares about one thing, and can't change the subject".

Has TDT been mentioned in HPMOR in the story before?

TDT specifically is not mentioned, but chapter 33 includes a discussion of superrationality as applied to the one-shot prisoner's dilemma.

Eliezer is on a mission to save the world from UFAI. TDT is an important part of that mission, reductionism not as much.

What's your confidence in your hypothesis?


Most likely alternative is that all the action involving the time-turner is focused on breaking the 6 hour barrier. I'm 97% sure that time turners will be pushed past their previous limits in some way.

If we were making a bet at odds determined by that probability assignment, how would you word the terms? (I ask because you said elsewhere "I don't think TDT will be mentioned explicitly", which might indicate that some of my objections don't apply to what you're actually thinking.)

85% that Harry will overcome some supposed or previously seen limitation to the Time Turner by absolutely coordinating his desires and actions across multiple Harrys (beyond being careful to not do anything to a different self that he did not previously perceive, which he has already done, for instance when he writes down the password he has already spoken to McGonagall even though he wonders if he shouldn't need to; this is an example of him building up to something more dramatic by careful pre-commitment); in other words by making his decisions without regards to sequence or perceived time, even if this tests his mettle. One possibility is that he will coordinate multiple selves without an invisibility cloak, which has been a precautionary measure so far, but I won't limit myself to that.

40% that this self-coordination involves an unbreakable vow.

97% that he will overcome some supposed or previously seen limitation to the Time Turner by any means.