My wife and I have just finished the first season of Dark on Netflix. I’m not a sci-fi fan–I know, it’s a real, moral shortcoming on my part–but Dark poses questions about time travel that wakened my inner philosopher. I can say this about one of the story arcs without giving away too much: a character walks through a wrinkle in time and comes out in the same place he had been, but 33 years earlier. One of his friends figures out what happened, and goes to 1986 to try to bring him back. However, if the first person is rescued and comes back to the present, he would not become a father. What would happen to people he never created?
Philosophers and physicists have long debated the efficacy of time travel. The conundrum these two characters face is known as the grandfather paradox:
The dead giveaway that true time-travel is flatly impossible arises from the well-known “paradoxes” it entails. The classic example is “What if you go back into the past and kill your grandfather when he was still a little boy?”…So complex and hopeless are the paradoxes…that the easiest way out of the irrational chaos that results is to suppose that true time-travel is, and forever will be, impossible. (Asimov, 2003, 276–7)
Other philosophers have raised valid objections to Asimov. It seems that the Theory of Relativity also opens up the possibility of time travel because of the existence of closed timelike curves.
So. . .to get back to Dark, what’s the easiest way to articulate the possibility that time travel exists AND that traveling backwards in time can result in changes to the present?