The Paradox of Time Travel

Deja Vu with Denzel Washington is one of my favorite time travel movies. It paints a world that to me is the most realistic time travel universe, which is why I love it. But you get this sort of loop with many other movies, some other even more impossible, like predestination,. Which is based on all you zombies. And so there, this would be extremely hard to imagine, you know, how you end up in this loop.