this post was submitted on 10 Apr 2024
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Showerthoughts
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A "Showerthought" is a simple term used to describe the thoughts that pop into your head while you're doing everyday things like taking a shower, driving, or just daydreaming. The best ones are thoughts that many people can relate to and they find something funny or interesting in regular stuff.
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Not exactly true. Technically, paradox free time travel would theoretically be possible.
As long as the time travel follows the Novikov self-consistency principle, there's no need for parallel universes.
Essentially the type of time travel employed in Harry Potter and the Prisoner of Azkaban. So you wouldn't be able to change anything, even if you did do things — as if you did something, it had always already been done previously (before you travelled back).
It is true, don't waste my time.
"it's a fun fiction which is always contradictory in some way" <-- that is not true.
General relativity allows for closed time-like curves and the existence of those means time travel isn't necessarily impossible, and if that is the case, it has to abide by the Novikov self-consistency principle.
Willfull ignorance wastes only your own time.
In that case time travel would be meaningless regardless, impossible to prove, and doesn't matter.
Dumbledore disagrees. The type of timetravel that happens in HP: Prisoner of Azkaban is self-consistent. Same as with Rick's timetravel in the snake episode of Rick & Morty (specifically excluding the snake time travel, which is an example of non-consistency, leading to endless paradoxes).
Now ofc having a timeturner and/or a timemachine would be the impossible part there, but again, CTC's are technically allowed by GR.