Kathryn Janeway ended the time travel debate in a 1998 episode of Star Trek: Voyager
Star Trek: Voyager deserves more love than it gets and the only reason it was ever maligned in the first place, I believe, is due to over-saturation. Had it been its own show away from The Next Generation and Deep Space Nine, it would’ve been a far more beloved show. They tackled so many amazing ideas, one of which came in the episode “Timeless”.
In this season five episode, the Voyager ship was destroyed after trying to activate an experimental slipstream drive that would shave off years of travel to Earth. In doing so, Kim makes a miscalculation and in doing so, causes Voyager to crash land, killing everyone on board.
Only Kim and Chakotay survive, as they were in a shuttle ahead of Voyager when things went array.
The two men, 15 years later, decide that they’re going to try and rewrite history. They’re able to send a message back to a Seven of Nine, allowing them to make the crew alterations necessary to bring the slipstream experiment to save end.
Later, Kim realizes that the correct calculations sent to Seven of Nine came from him, but a future him. This is where Kim, while talking to Captain Kathryne Janeway, falls in on himself trying to understand how all of it was possible. How could the future Kim send the calculations back in time, averting the destruction of the ship, and saving the crew, yet still exist to send the calculations back?
Kathryn Janeway solves years of debate about time travel with some simple sentence
As Kim does more mental gymnastics than an Olympian while trying to solve his time paradox, his captain gives him a strong piece of advice that would best be served in talking about all time paradoxes, both real and fictional;
"My advice on making sense of temporal paradoxes is simple: don’t even try. – Janeway"
It’s simple, sweet, and to the point. While they soothed Kim, they also serve as real words of advice for people who want to debate poorly written time travel movies and shows; like Avengers: End Game. There’s a giant plothole(s) there, but if you pick at it, all you’re going to do is give yourself a headache.
So take Janeway’s advice. The next time you want to deconstruct the time travel mechanics in Hot Tub Time Machine or Back to the Future; just don’t.