Trope-a-Day: Temporal Paradox
Temporal Paradox: It’s a block universe; the short form would be to say that predestination paradoxes are permitted (although the non-informational kind are tricky) and grandfather paradoxes are not, since even though you can violate local causality, global causality is always preserved.
And if you find yourself caught up in one of these, You Can’t Fight Fate. You may, however, be able to cheat, if there’s a chance – and there usually is a chance – that what you thought happened first time through might will be not have been what actually happened.