Also known as the "Grandfather's Revenge Paradox," this paradox is a real head-scratcher. In short, if your grandfather had a time-traveling clone, and that clone had a time-traveling clone, and so on, ad infinitum, then your grandfather's actions in the past are predestined to happen, because his clones have already done them.
But here's the kicker: if you're the one doing the predestining, you're stuck in an infinite loop of "your grandfather's" actions, forever doomed to repeat the same events, like some sort of cosmic Groundhog Day.
We're not sure what's more disturbing – the paradox itself, or the fact that it's named after a mathematician who didn't even like it that much (Igor Novikov, 1946-2023, R.I.P).
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