Sn there is no evidence that the pre destination theory is present, according to these films, the only part of the future which is not written is time travel. That doesn't mean it's not possible, we seem to see it from the first occurance.
Originally Posted by riojdn
Now I got more confused. I think I will have to watch the series one more time.
Thanks for all the inputs though. Now I have to think about other movies too, like Source Code, Frequency, and Time Traveler's Wife. OMG.
I'll help you.
Source code is pretty easy since all the events are within the same day.
Frequency; kind of a hybrid of time travel theories. The timeline does get changed (not through time travel but communication with the past) and it indicates the future son remembers both timelines (which is Sn's theory of what should happen with Marty.
Time Traveler's wife; does not follow the same rules as BTTF. According to this film, time travel is already written into the timeline (much like 12 monkey's) so there are no alternate timelines or paradoxes. For instance we see the main character attempt to save his mother's death several times without success. He realizes whatever is meant to be is meant to be and the timeline can't be changed.