After reading and loving Stephen King's 11/22/63 a few months ago, I've been on a time-travel kick, scouring the web for lists of "best time-travel books" and following the threads of influence from one to another. One of the first places that this search led me was to Jack Finney's Time and Again, a novel about a man named Si Morley who works as part of a government project to see if time travel is possible.
As explained by one of the directors of the project Si works for, the basic premise of time travel in Finney's novel is this: time is like a river, and we currently exist at one point on the river, but past points on the river still exist--they're not gone. All you have to do is cut the threads that are holding you to the present and establish threads to a point in the past, and then you can convince yourself that you are in, say, 1882, rather than in the present day. It's a fascinating idea, and I actually learned a lot about the history of time from this novel--did you know, for instance, that up until 1883, time in the United States was kept locally? This meant that each major city or railroad station set its own time, making train timetables quite confusing. I didn't realize this, and it was a fascinating reminder of how much the idea of time is a very human creation, rather than something that absolutely exists on its own.
What was also interesting about the conception of time in Finney's novel, though, is how much time travelers are able to change the past--and how different this idea is from other authors' speculations about this question.
In Finney's novel, time is described as being like a river--not only in terms of being able to access past points on the river, but also in terms of how much someone is able to change the past. If a person makes a minor change, for instance, akin to dropping a twig in a river, it doesn't really make that much of a difference--the current of the river is so strong that everything will get rushed downstream in the same way anyways.
This seems quite different from the other popular idea of time travel and chaos theory, which is nicknamed "the butterfly effect." In this formulation of time travel, even the smallest, seemingly inconsequential changes can make big differences--Ray Bradbury's "A Sound of Thunder" is perhaps the most famous example of this, a story in which a man who travels back in time on a safari to kill a Tyrannosaurus Rex steps off the prescribed path and steps on a butterfly; when he returns to the present, he sees that many things about the present have changed for the worse, much to his dismay.
In other words, it seems that there are two main ways of thinking about time and time travel--either the events of time are pretty much fixed and unchangeable, regardless of what humans do (like the course of a river), or the slightest change can set off an alternate series of events, changing the course of human history forever (the butterfly effect).
Of course, it's not that simple, and many books and movies fall somewhere along a continuum between these two points, but it's interesting to think about the famous stories of time-travel and note which of these two main ideas they come closer to--are they a river or a butterfly time travel story?
[warning: spoilers about well-known time-travel stories follow]
Back to the Future? Well, Marty disrupts his parents' meeting when he gets hit by the car instead of his dad--sure, this is a fairly significant event in his timeline, rather than a minor one, but the effort that he has to go to to get his parents back together suggests that this is a world in which time is easily disrupted. Verdict: butterfly story
Twelve Monkeys? This one seems fairly clear--James Cole (Bruce Willis' character) is sent back in time to prevent a deadly virus from being released, but at the end of the movie, we realize that he's just in a loop where his actions contribute to the release of the virus. Verdict: river story
Doctor Who? Now, I can't speak for the classic Who, but based on what I've seen of the "new Who," it seems that this TV series presents time as more or less fixed. The events that happen happen for a reason--to change that would risk worse things happening. Take "The Fires of Pompeii," for instance--the Doctor can't save the town of Pompeii, because to do so would be to risk a disruption in the fabric of time. The best he can do is save one family. And in The Waters of Mars, even when the Doctor decides to break the rules and save the crew of the Mars mission, time reasserts its authority and the captain kills herself anyways. Verdict: river story
11/22/63? The influence of Jack Finney's novel is very clear here, particularly in the way that King presents time. When Jake Epping travels back in time to try to prevent the JFK assassination, he comments, over and over, that he feels time fighting against him, trying to prevent him from making these changes. Verdict: river story
And quite frankly, I'm more comfortable with the idea of time as a river. I don't like the idea that any little thing that I do can change the whole outcome of human history. It's much more reassuring to think that, regardless of what decisions I make, things will happen as they are meant to happen.
It sure makes choosing what to wear in the morning less of an existential drama.
By Jen Miller