Thursday, May 31, 2012

Time Travel Limitations


I just finished watching Slaughterhouse-Five, the 1972 film adaptation of Kurt Vonnegut, Jr.'s novel (1969) of the same name.  Back when I used to get DVDs from those mail order clubs, this film was always prominently featured but I never ordered it.  So it was nice to finally see it.  The biggest thing that strikes me about watching these older flicks is how many ideas that I once thought as unique in more recent movies may actually have come from the older film.  For instance, the scenes with Billy Pilgrim in the dome being observed by the omni-present but unseen Tralfamadorians who wanted the humans to perform made me think of The Truman Show by Peter Weir, Andrew Niccol and Jim Carrey.  

But the main concept from Slaughterhouse that I wish to explore is this idea that our main character jumps through time but only within his own lifetime.  For Slaughterhouse-Five each time period is about the main character so it is relevant that the time travel be limited to his lifetime.  What I find interesting is that this concept is also the main theme to Quantum Leap by Donald Bellisario, Scott Bakula and Dean Stockwell, where Dr. Sam Beckett jumps through time into other people's lives but only during his own lifetime.   

Why only during his own lifetime? 

Another show that comes to mind is Journeyman (2007) by Kevin Falls and Kevin McKidd.  This was a short-lived TV show where the main character jumps through time but unlike Leap he is seen as himself from his native time.  However, similar to Quantum Leap the protagonists' objective is to help someone. 

Donnie Darko is a little different.  This movie allows the viewer to witness parallel lifetimes and most of the events occur within one of the timeframes of Donnie's life but apparently events from this timeline can affect the other timeline.  Or Donnie has a superpower.  I need to re-watch this again to really get a grasp on what happens when.  However, I'm not so sure that this film applies to the question that I am attempting to address here.

There are plenty of websites that categorize the different time travel rules that have been established in Sci-Fi.  Such as the timeline is fixed and nothing can change it (Terminator) or you can go back change something that might erase your existence (Back to the Future), etc.  So I won't attempt to define all the different theories of time travel here. 

The reason for this posting
I'm sure there are other films and probably ten times the number of books with this common theme of jumping through time with the caveat of the time frame being limited to one's own lifetime.    I'd be interested in hearing from those who know better than I, what these other books and films are.  I'm curious as to where the idea for this limitation was conceived and how its been applied to help explain why this limitation should or should not exist.

It'd be uninteresting to find that this concept simply originated from Slaughterhouse-Five.  I suspect that it may have been suggested in a Star Trek episode or an even earlier sci-fi short story.  I suppose the immediate benefit of limiting travel to one's one lifetime is that there's less chance of one person completely altering life on Earth as we know it in the present, since one can only go back 20-60 years.  Plus it limits the vast majority of characters living in 2012, for instance, from going back to influence some profoundly significant event like Pearl Harbor or the JFK assassination.  Another benefit is that the traveler can never be certain of when they die since they could only theoretically travel up to that moment but not see beyond it to know for sure if that is when they ceased to breath.  Therefore, this limitation reduces the chance that a character would become motivated to prevent their demise .