As an author I have written 8 science fiction novels all under the umbrella concept of ‘the afterlife’. Many of these stories concern time travel in some form or another and in any case I have always had a life long fascination with any stories about travelling in time. Does that make me some kind of self educated expert on the subject?
You decide but in any case I believe that I can resolve the well known ‘grandfather paradox’ where a man travels back in time and kills his own grandfather before that man has time to have a son to be the father of the time traveller who is now also never born so that he never goes back in time and never kills his grandfather etc. etc. ad infinitum.
One theory that has been around for a while is that whatever changes that are made in the past are destined to have happened so that the time traveller simply becomes the instrument of what is supposed to happen. Let’s say someone travels back in time and shoots Lee Harvey Oswald before he kills President Kennedy. Does that mean that Kennedy lived and history was completely changed or would there be another gunman thrown up by history who would kill Kennedy at the appointed time?
Now I am also a student of Physics and it turns out that Quantum Mechanics has a bit to say about all this. One theory has it that EVERYTHING that is possible to happen ACTUALLY HAPPENS! This goes right down to the sub particle level where every possible collision and interaction in time and space actually takes place in what we may call the ‘meta-universe’.
On a personal level let’s say that for whatever reason you decide to dissolve your marriage. In this theory there is another version of you somewhere in a different universe that decides to stick with your partner and to make a go of your marriage together with having children and everything else that follows on. In fact every infinitesimal quantum of time is a branch point for a different decision.
Now how about we keep things real simple and try to resolve the ‘grandfather paradox’. We’ll call our intrepid time traveller James Smith. Now James goes back in a time machine to a point in time when his grandfather (let’s call him John Smith) is a young man. James shoots and kills John Smith before this man is even married and so prevents his would be son, John Smith Jr. from ever being born or ever having a son called James. We’ll call this the A-timeline.
Now what this rather important change does is to spin off another timeline which we can call the B-timeline. Actually it’s only one of an infinite number of possible timelines branching from this point or any other point but I said we would keep this simple.
James now decides to return to the present but what does he find? If he travels up the B-timeline he will find no reference to himself or his father but he could find a reference to a John Smith who was murdered at age twenty by an unknown person but this John Smith would have no connection to young James who is simply a visitor to this timeline. If James returns to the A-timeline present he may find a duplicate of himself depending on whether he returns before or after he made the original jump. In either case his grandfather will be very much alive as will his father because he did not shoot this particular version of his grandfather.