Which theory of time travel do you think is more accurate?
-If you go back in time and do something, it wouldn't cause anything in the future to change because it had already happened. (eg. In Harry Potter and the Prisoner of Azkaban and in Artemis Fowl and the Time Paradox)
-If you go back in time and do something the future will change drasticly.
I think the first theory is more accurate because if the second theory was correct and you kill your grandfather or something you wouldn't exist to go in time and kill your grandpa.