POTENTIAL PLOT HOLE! PLEASE DEBATE
I just want to say that I liked the movie, but the ending of the movie made me think long and hard about the whole story.
If Jack's present timeline (1992) is directly affected by the future timeline that he was allowed to go to (2007), and there was a direct cause and effect relationship, then how was it possible that he changed the future?
I understand that there are different forms of time travel, and different theories and paradox but I feel like this movie was contradicting itself. Throughout the movie, we can see that BECAUSE Jack goes into the future of 2007, he is THEN able to help the doctor cure her friend's kid with shock therapy. It is also BECAUSE the evil doctor told him about the past victims, that he THEN knows about it and tells it to the evil doctor in the 1992 timeline. Going on this logic, it can be safe to say that everything he does or is about to do is pre-determined since his present is a product of seeing into his future.
And towards the end, if he NEVER had the motivation to write a letter to that chick he banged in the future, then he would've never gotten into that car with that doctor to drive to her house. IF HE NEVER GOT INTO THAT CAR, THEN HE NEVER WOULD'VE DIED/GOTTEN THAT HEAD TRAUMA BY SLIPPING. SO IF THIS IS THE CASE, that means everything was already pre-determined because he would've never grown to care for that chick so much if he was not even allowed to go in the future in the first place. So if his present timeline 1992 was a direct result of his knowledge of the future, then it would have never changed the future a single bit by writing that letter because that letter indirectly caused his death.
SO THIS IS A PLOT HOLE!