This seems like it’s consistent with how time-turners look to their users, but it’s not so clear that it fits with how their use looks to other people. Wouldn’t you expect that (something like) half of all time-turner uses by people other than oneself would appear to fail (i.e., the user vanishes but there’s no sign that they reappeared at an earlier time)?
Much less than half the time. Remember, if Harry1 uses his time turner, he creates Universe2 with Harry2=Harry1_6_hours_ago. But in 6 hours, Harry2 will use his time turner, creating Universe3 with Harry3...
So IF there is a stable time loop of any kind, most universes will have that loop.
This raises the interesting prospect of stable sets of universes, with 6-hour histories A, B, and C. If a Harry that experiences A uses his time turner and does B, and a Harry experiencing B does C, and Harry experiencing C does A, then most copies of Harry will experience an inconsistent time loop, and it will seem like he actually went back and changed time.
If time loops are generally observed to be consistent, then this is evidence that single-state equilibria are much more probable than multiple-state equilibria.
Wouldn’t you expect that (something like) half of all time-turner uses by people other than oneself would appear to fail (i.e., the user vanishes but there’s no sign that they reappeared at an earlier time)?
No, the user does not vanish, it’s just half the time time-turner appears to do nothing. Fortunately, the story line both in canon and in HPMoR only traces the path where time-turners work.
How is that consistent with “transports the wearer to that branch” from your description?
the story line … only traces the path where time-turners work.
Huh? That’s like presenting a story in which one character has a magic pair of dice that always roll 12, and then explaining that how they “work” is that they make the universe branch 36 ways, and in one branch they roll 12 -- and the story “only traces the path where they always rolled 12″.
In fact, it’s worse. No one who talks about time turners in the story (either canon or HPMOR) says anything like “for some reason, other people’s time turners often fail, but you’ll never find your own doing so”; there is no suggestion that any such thing has been observed. So is the story “only tracing the path” where nearly all past time-turner use happens to have gone down the “good” branch?
How is that consistent with “transports the wearer to that branch” from your description?
Oh, I guess I was unclear. Time-turner does not delete a person from a timeline, this is expensive, unnecessary and violates General Relativity. A new copy of the wearer is inserted in the branched timeline where none was before.
In fact, this insertion is the only part of the time-turner’s description that is questionable under any known physical laws: It takes either energy momentum non-conservation or both FTL matter transmission and Lorentz invariance breaking to create something from nothing.
So is the story “only tracing the path” where nearly all past time-turner use happens to have gone down the “good” branch?
On a charitable interpretation: every story ever written (excluding directly self-contradictory ones) describes a universe (quantum branch) which exists. Choice of story to write == choice of universe evolution to describe. Shminux just told you what evolution is described by HP stories. It’s about as valid as saying “here’s a story where magic works, although it never does in our own universe, and the reason is—there’s such a universe out there and we just chose to tell its story”.
Does that actually explain anything more than saying “it’s magic, and here are its laws” would? Probably not. But it’s still a perfectly valid statement to make.
Does that actually explain anything more than saying “it’s magic, and here are its laws” would?
As I mentioned in the other comment, except for the actual appearance of a person from nowhere in the branched timeline, no laws of physics are broken.
This seems like it’s consistent with how time-turners look to their users, but it’s not so clear that it fits with how their use looks to other people. Wouldn’t you expect that (something like) half of all time-turner uses by people other than oneself would appear to fail (i.e., the user vanishes but there’s no sign that they reappeared at an earlier time)?
Much less than half the time. Remember, if Harry1 uses his time turner, he creates Universe2 with Harry2=Harry1_6_hours_ago. But in 6 hours, Harry2 will use his time turner, creating Universe3 with Harry3...
So IF there is a stable time loop of any kind, most universes will have that loop.
This raises the interesting prospect of stable sets of universes, with 6-hour histories A, B, and C. If a Harry that experiences A uses his time turner and does B, and a Harry experiencing B does C, and Harry experiencing C does A, then most copies of Harry will experience an inconsistent time loop, and it will seem like he actually went back and changed time.
If time loops are generally observed to be consistent, then this is evidence that single-state equilibria are much more probable than multiple-state equilibria.
Note that this explanation does not require Magic to simulate or calculate anything aside from creating a copy of a past state of the universe.
No, the user does not vanish, it’s just half the time time-turner appears to do nothing. Fortunately, the story line both in canon and in HPMoR only traces the path where time-turners work.
How is that consistent with “transports the wearer to that branch” from your description?
Huh? That’s like presenting a story in which one character has a magic pair of dice that always roll 12, and then explaining that how they “work” is that they make the universe branch 36 ways, and in one branch they roll 12 -- and the story “only traces the path where they always rolled 12″.
In fact, it’s worse. No one who talks about time turners in the story (either canon or HPMOR) says anything like “for some reason, other people’s time turners often fail, but you’ll never find your own doing so”; there is no suggestion that any such thing has been observed. So is the story “only tracing the path” where nearly all past time-turner use happens to have gone down the “good” branch?
Oh, I guess I was unclear. Time-turner does not delete a person from a timeline, this is expensive, unnecessary and violates General Relativity. A new copy of the wearer is inserted in the branched timeline where none was before.
In fact, this insertion is the only part of the time-turner’s description that is questionable under any known physical laws: It takes either energy momentum non-conservation or both FTL matter transmission and Lorentz invariance breaking to create something from nothing.
On a charitable interpretation: every story ever written (excluding directly self-contradictory ones) describes a universe (quantum branch) which exists. Choice of story to write == choice of universe evolution to describe. Shminux just told you what evolution is described by HP stories. It’s about as valid as saying “here’s a story where magic works, although it never does in our own universe, and the reason is—there’s such a universe out there and we just chose to tell its story”.
Does that actually explain anything more than saying “it’s magic, and here are its laws” would? Probably not. But it’s still a perfectly valid statement to make.
As I mentioned in the other comment, except for the actual appearance of a person from nowhere in the branched timeline, no laws of physics are broken.