Many people seem to suggest time-turner tricks for Harry to hide Hermione body. But that raises a few issues to me :
Do we have any evidence for or against the fact that the Hogwarts wards, or more generally a spell that Dumbledore could cast, would inform him of the usage of time-turner inside Hogwarts ? There is mention of “anti-time-loop ward”, could there be “time-loop detecting wards” ?
Dumbledore didn’t seem to check if Harry used his time-turner or not, and he didn’t even ask him if he did. That’s suspicious. It seems surprising that Dumbledore goes to great length to do a careful check of Harry’s belonging, despite the social cost of doing so, and yet, not a single mention of the time-turner. Not even casually like the portkey. From an “outsider” point of view, it points to the fact Harry used it. Or at least, it would from many authors, but such a “oh well the NPC just didn’t think about that major plot device” hand-waving doesn’t seem at all to be Eliezer’s way of doing things.
Time-Turners are in frequent and authorized use by a fair number of students, as well as Dumbledore himself and possibly other staff members. Any such ward would be constantly triggering, for no particularly important reason. Even if one exists, I can’t imagine that Dumbledore pays much attention to it.
Dumbledore is only looking for Hermione. There’s no reason for him to be much interested in Harry’s magical devices, beyond proving that they aren’t Hermione. The portkey was only mentioned because it was a part of Dumbledore’s body search; the Time-Turner, presumably, wasn’t on his body.
People have suggested that on being summoned to the Headmaster’s office, Harry precommits to time-turn back and hide Hermione’s body before the summons arrives. Whether that means replacing the ring or the stone or what have you.
There are several ways I can think of that Dumbledore could circumvent this:
keep Harry under observation for the next six hours, magically or otherwise
force Harry to use all six turns immediately, and then keep him under observation for six hours
check the Map (if he’s the one who currently holds it; do we know at this point?) for multiple instances of Harry—a second Harry would be evidence that he’d been engaged in time-turner shenanigans
The first two methods seem wasteful. High cost compared to the relatively trivial transfiguration check. So if Dumbledore has other suspects besides Harry, he might not deem it worthwhile. The third is simple enough, if Dumbledore does have the Map. And if the Map does display multiple instances of time-turned people, as seems likely—I think this has been discussed as possibly being one of the “errors” the twins note.
Which still leaves the question of whether Dumbledore does have it.
Regarding 2- possible explanations. First, it is possible that Dumbledore knows already about some set of Time-Turner use which is about to happen for (from his standpoint) completely separate legitimate reasons. Second, it is possible that there’s no easy way to check if a Time Turner has been used other than to see if it can still be used (see the earlier instance where they checked if Harry’s Turner had been used by having him deliver a specific message to the past), and given the precarious nature of the situation, Dumbledore doesn’t want to waste any of Harry’s Time-Turner hours if he can avoid it.
there’s no easy way to check if a Time Turner has been used other than to see if it can still be used
If the turner also has a restriction[1], it’s easy to check: just ask someone not important to try to use it. (Not important in the sense that it’s no big deal if they loose the ability to time-turn for a day).
[1:] It should have. They can be broken/destroyed, which suggests that they can also accumulate non-fatal damage (like scratches), which technically means that they also carry information to the past. But the information rules don’t seem to apply except when in some cases involving sentience.
It wasn’t clear to me whether it was one or both. I got the impression that it was both. At minimum it should include the user just from the rule about not being able to send information back more than six hours.
Actually, it’s probably neither, just information, albeit with apparent weird rules about consciousness.[1] It’s enough for someone from the future to tell you something to prevent you from going back, even if you didn’t use a time-turner.
[1:] Otherwise, nobody could time-turn from inside the light-cone of someone who just time-turned six hours. The gravitational attraction from Amelia Bones’ stomach contents carries information about the future, for example. So something has to check for some kind of observers. Incidentally, that does sound plausible if the source of magic has specific rules for sapience, à la Prime Intellect.
I’d always just assumed that whatever force imposes the time turner rules just has a simple constraint that no history is permitted where “information” travels back further, and it freely reconfigures things in potentially very high entropy ways (“DO NOT MESS WITH TIME”) to achieve that end. Amelia Bones’ upon time travel was replace with a spherical null-information amelia bones which had no influence from the future except that which she would not covey— including by choice— to anyone that travels outside the constraint satisfaction window.
So I think there doesn’t need to be any special casing of sapience to create the appearance of special casing sapience, beyond anthropic bias— the only time when the reconfiguration to meet the constraint is particularly obvious to a conscious entity is when it interacts with a conscience entity.
Off the top of my head, something that simple doesn’t seem to match with the apparent safety of time-turners. Something that just reconfigures things “freely” will reconfigure stuff dangerously on occasion. Even if the time-turner will hide the reconfiguration, people will probably notice something like “there’s bad luck around time-turners”.
Note that things that appear “simple” to humans are not so at small scales. It’s much simpler for someone that time-turns to become insane or even just die rather than remain the same person except not speaking of some things.
Also, “information” is tricky. At some point in one of the new chapters, Minerva notices that Harry seems different only a few minutes after having entered a closed room. Let’s assume for now it’s because he’s from the future. (E.g., the one that entered is still in the room, under the cloak, and will return after six hours to exit the room.) If she doesn’t realize it, can she still time-turn? What if she finds out something that confirms it after five minutes, is she blocked then? Is she blocked if she deduces with high certainty something about the future from the fact that Harry returned. (At the minimum, if she realizes that Harry came back, she learned that he will not die in the next six hours.) What if she turns back six hours, and in the past she learns a piece of information that allows her to deduce with whatever level of certainty both that Harry went to the future, and something about what he did there?
(Example: at 1PM Harry builds a one-time pad and hides it. 12 hours later, he writes something about his present and XORs it with the one-time pad. He turns back six hours, and tells the encrypted text to Hermione, who memorizes it. Can she turn? She doesn’t really know anything more about the future than if he would have told her “I have information from six hours in the future”. But if she now turns back another six hours and finds the one-time pad, she’ll be able to obtain the information from 12 hours in her subjective future.)
Well— we’re deep in the meta philosophy of a fictional world, so I’m not sure that any great insight will come from the discussion.
I’m unsure of how to resolve the apparent safety of time tuners with the idea that there is an optimization process selecting a permissible outcome unless I wave my arms and say that the optimization process is moral, perhaps borrowing the objectives of the operator (like the sorting hat). One way to do this is to note that bad things happening increase the probability of more time tuner usage, which a human-interest blind metric could still be minimizing.
Seems very handwavy, though: Saying the optimizer picked tie breaking that— say— minimized the sum probability change displaced in times would just tend to select time tuners out of existence.
As far as information itself, I’m not so sure if it’s quite that sticky: Imagine our universe as we normally would think of it but with quantized time (tics). We would normally imagine a each tick having a state and then there is some (large but) finite number of successor states possible, each with its own probability which is simply the product of the probabilities of all the component transitions for all the particles. The universe evaluates this function a step at a time moving to a particular new state with probabilities proportional to product the component particle transition probabilities according to natural law.
In HPMOR verse, instead the evaluation gets performed by some hyper-computer that evaluates the states using a six hour look-ahead. You could imagine taking the every possible combination of 6 hour successor states and picking according to their joint probability, then stepping forward one tick towards the selected group and then redoing the evaluation. At least in classical mechanics you don’t need the look ahead evaluation but MORverse has time tuners.
As seconds fall out of the tail of the window they become fixed. Prior to that happening time tuner usage upwhen can influence the selected states in the downwhen subject to the constraints that no inconsistency is created. If Minerva noticing harry seemed different would have created some contradiction (due to it influencing into time travel that went into the fixed downwhen) then she simply wouldn’t. The picking of the “most likely” way to constrain her from (e.g. having her drop dead) is precluded by having to be consistent with the past history which is already fixed and doesn’t include any dangerous interactions.
Stated differently: danger would arise only because of time travel into a past that was fixed before the cause of the danger was available to the evaluator. Unsafe resolutions would tend to not be consistent with the fixed past. So the normalcy of constrained time travel might simply be a result of the forward lookahead and the backwards modification depth being exactly the same.
Many people seem to suggest time-turner tricks for Harry to hide Hermione body. But that raises a few issues to me :
Do we have any evidence for or against the fact that the Hogwarts wards, or more generally a spell that Dumbledore could cast, would inform him of the usage of time-turner inside Hogwarts ? There is mention of “anti-time-loop ward”, could there be “time-loop detecting wards” ?
Dumbledore didn’t seem to check if Harry used his time-turner or not, and he didn’t even ask him if he did. That’s suspicious. It seems surprising that Dumbledore goes to great length to do a careful check of Harry’s belonging, despite the social cost of doing so, and yet, not a single mention of the time-turner. Not even casually like the portkey. From an “outsider” point of view, it points to the fact Harry used it. Or at least, it would from many authors, but such a “oh well the NPC just didn’t think about that major plot device” hand-waving doesn’t seem at all to be Eliezer’s way of doing things.
Time-Turners are in frequent and authorized use by a fair number of students, as well as Dumbledore himself and possibly other staff members. Any such ward would be constantly triggering, for no particularly important reason. Even if one exists, I can’t imagine that Dumbledore pays much attention to it.
Dumbledore is only looking for Hermione. There’s no reason for him to be much interested in Harry’s magical devices, beyond proving that they aren’t Hermione. The portkey was only mentioned because it was a part of Dumbledore’s body search; the Time-Turner, presumably, wasn’t on his body.
People have suggested that on being summoned to the Headmaster’s office, Harry precommits to time-turn back and hide Hermione’s body before the summons arrives. Whether that means replacing the ring or the stone or what have you.
There are several ways I can think of that Dumbledore could circumvent this:
keep Harry under observation for the next six hours, magically or otherwise
force Harry to use all six turns immediately, and then keep him under observation for six hours
check the Map (if he’s the one who currently holds it; do we know at this point?) for multiple instances of Harry—a second Harry would be evidence that he’d been engaged in time-turner shenanigans
The first two methods seem wasteful. High cost compared to the relatively trivial transfiguration check. So if Dumbledore has other suspects besides Harry, he might not deem it worthwhile. The third is simple enough, if Dumbledore does have the Map. And if the Map does display multiple instances of time-turned people, as seems likely—I think this has been discussed as possibly being one of the “errors” the twins note.
Which still leaves the question of whether Dumbledore does have it.
Regarding 2- possible explanations. First, it is possible that Dumbledore knows already about some set of Time-Turner use which is about to happen for (from his standpoint) completely separate legitimate reasons. Second, it is possible that there’s no easy way to check if a Time Turner has been used other than to see if it can still be used (see the earlier instance where they checked if Harry’s Turner had been used by having him deliver a specific message to the past), and given the precarious nature of the situation, Dumbledore doesn’t want to waste any of Harry’s Time-Turner hours if he can avoid it.
If the turner also has a restriction[1], it’s easy to check: just ask someone not important to try to use it. (Not important in the sense that it’s no big deal if they loose the ability to time-turn for a day).
[1:] It should have. They can be broken/destroyed, which suggests that they can also accumulate non-fatal damage (like scratches), which technically means that they also carry information to the past. But the information rules don’t seem to apply except when in some cases involving sentience.
Wait a moment, is it the Time-Turner or the user who is limited to six hours?
If it’s the time turner, it’s odd that Dumbledore checked whether Harry could time turn, rather than his time turner.
Not really.
Functionally equivalent for his test.
It wasn’t clear to me whether it was one or both. I got the impression that it was both. At minimum it should include the user just from the rule about not being able to send information back more than six hours.
Actually, it’s probably neither, just information, albeit with apparent weird rules about consciousness.[1] It’s enough for someone from the future to tell you something to prevent you from going back, even if you didn’t use a time-turner.
[1:] Otherwise, nobody could time-turn from inside the light-cone of someone who just time-turned six hours. The gravitational attraction from Amelia Bones’ stomach contents carries information about the future, for example. So something has to check for some kind of observers. Incidentally, that does sound plausible if the source of magic has specific rules for sapience, à la Prime Intellect.
I’d always just assumed that whatever force imposes the time turner rules just has a simple constraint that no history is permitted where “information” travels back further, and it freely reconfigures things in potentially very high entropy ways (“DO NOT MESS WITH TIME”) to achieve that end. Amelia Bones’ upon time travel was replace with a spherical null-information amelia bones which had no influence from the future except that which she would not covey— including by choice— to anyone that travels outside the constraint satisfaction window.
So I think there doesn’t need to be any special casing of sapience to create the appearance of special casing sapience, beyond anthropic bias— the only time when the reconfiguration to meet the constraint is particularly obvious to a conscious entity is when it interacts with a conscience entity.
Off the top of my head, something that simple doesn’t seem to match with the apparent safety of time-turners. Something that just reconfigures things “freely” will reconfigure stuff dangerously on occasion. Even if the time-turner will hide the reconfiguration, people will probably notice something like “there’s bad luck around time-turners”.
Note that things that appear “simple” to humans are not so at small scales. It’s much simpler for someone that time-turns to become insane or even just die rather than remain the same person except not speaking of some things.
Also, “information” is tricky. At some point in one of the new chapters, Minerva notices that Harry seems different only a few minutes after having entered a closed room. Let’s assume for now it’s because he’s from the future. (E.g., the one that entered is still in the room, under the cloak, and will return after six hours to exit the room.) If she doesn’t realize it, can she still time-turn? What if she finds out something that confirms it after five minutes, is she blocked then? Is she blocked if she deduces with high certainty something about the future from the fact that Harry returned. (At the minimum, if she realizes that Harry came back, she learned that he will not die in the next six hours.) What if she turns back six hours, and in the past she learns a piece of information that allows her to deduce with whatever level of certainty both that Harry went to the future, and something about what he did there?
(Example: at 1PM Harry builds a one-time pad and hides it. 12 hours later, he writes something about his present and XORs it with the one-time pad. He turns back six hours, and tells the encrypted text to Hermione, who memorizes it. Can she turn? She doesn’t really know anything more about the future than if he would have told her “I have information from six hours in the future”. But if she now turns back another six hours and finds the one-time pad, she’ll be able to obtain the information from 12 hours in her subjective future.)
Well— we’re deep in the meta philosophy of a fictional world, so I’m not sure that any great insight will come from the discussion.
I’m unsure of how to resolve the apparent safety of time tuners with the idea that there is an optimization process selecting a permissible outcome unless I wave my arms and say that the optimization process is moral, perhaps borrowing the objectives of the operator (like the sorting hat). One way to do this is to note that bad things happening increase the probability of more time tuner usage, which a human-interest blind metric could still be minimizing.
Seems very handwavy, though: Saying the optimizer picked tie breaking that— say— minimized the sum probability change displaced in times would just tend to select time tuners out of existence.
As far as information itself, I’m not so sure if it’s quite that sticky: Imagine our universe as we normally would think of it but with quantized time (tics). We would normally imagine a each tick having a state and then there is some (large but) finite number of successor states possible, each with its own probability which is simply the product of the probabilities of all the component transitions for all the particles. The universe evaluates this function a step at a time moving to a particular new state with probabilities proportional to product the component particle transition probabilities according to natural law.
In HPMOR verse, instead the evaluation gets performed by some hyper-computer that evaluates the states using a six hour look-ahead. You could imagine taking the every possible combination of 6 hour successor states and picking according to their joint probability, then stepping forward one tick towards the selected group and then redoing the evaluation. At least in classical mechanics you don’t need the look ahead evaluation but MORverse has time tuners.
As seconds fall out of the tail of the window they become fixed. Prior to that happening time tuner usage upwhen can influence the selected states in the downwhen subject to the constraints that no inconsistency is created. If Minerva noticing harry seemed different would have created some contradiction (due to it influencing into time travel that went into the fixed downwhen) then she simply wouldn’t. The picking of the “most likely” way to constrain her from (e.g. having her drop dead) is precluded by having to be consistent with the past history which is already fixed and doesn’t include any dangerous interactions.
Stated differently: danger would arise only because of time travel into a past that was fixed before the cause of the danger was available to the evaluator. Unsafe resolutions would tend to not be consistent with the fixed past. So the normalcy of constrained time travel might simply be a result of the forward lookahead and the backwards modification depth being exactly the same.