That is known as the bootstrap paradox (http://en.wikipedia.org/wiki/Bootstrap_paradox http://en.wikipedia.org/wiki/Bootstrap_paradox). You could argue that the

That is known as the bootstrap paradox (http://en.wikipedia.org/wiki/Bootstrap_paradox http://en.wikipedia.org/wiki/Bootstrap_paradox). You could argue that the entire point of the movie is to highlight this specific paradox that can result from time travel. As with most time travel paradoxes, and pretty much anything related to time travel, it's not known exactly how things would work out in the real world.