Science fiction stories are stories about human ideas. They take these ideas and examine them from a number of angles. Hard Sci-Fi is all about technology and science – what will the ideas of our greatest scientists look like as they drive civilization for another one or two hundred years? Space opera is more about the ideas of society and sociology, how will disparate cultures interact in the future?
The problem with these genres is that they can rapidly loose touch with the individual. Since readers are individuals, and they will identify best with individual characters and not abstract ideas about “science” or “society”, that means that the readers can frequently loose interest in the story (which is bad.) Sure, some readers who buy into the author’s ideas will be totally enthused, but that just means the author’s appeal will be playing to the choir. But there is one great way to solve this problem.
What if all the major ideas the sci-fi story needs to advance could somehow grow out of the decisions or actions of one person? What if the consequences of that person’s decision(s) could be explored, not just in their immediate effects on the world around them but through their effects decades or centuries into the future? What if a person could know that their thoughts and actions would change the future – and what’s more, choose what kind of a legacy they were leaving?
That “what if” is the core of the time travel story, a kind of sci-fi that lets a single person shape reality in fantastic ways by traveling through time. Time travel stories are tricky from the genre standpoint, as they are both a thing of their own and tend to be lumped into a dozen other subgenres of science fiction. They can be anywhere on the scale of sci-fi hardness and may be set in a space opera setting or confined entirely to Earth. But they will have a few things in common.
Some way for a character or characters to travel through time. This sounds like it should be obvious, but hey. It’s a fact. If no one’s traveling through time, or at least seeing through time, then we’re not dealing with a time travel story. Note that the direction of the time travel doesn’t matter. People can be going backwards to meddle in the history of the Roman Empire or dashing forwards to get lotto numbers and strike it rich, they only need be traveling through time. (Going “sideways” to alternate realities doesn’t count. Slider stories and alternate history will have their own entry thank you very much.) If you want to be really generous, stories with clairvoyants who can predict the future can kind of fall into this genre too. I am not so generous, but you can be if you want.
The consequences of some action taken, and the ability to alter them with time travel, are central to the conflict of the story. Watch the classic Star Trek episode The City on the Edge of Forever for a detailed example. In the typical time travel story one of two things happens – either the protagonist meets a time traveler who has come back to avert a coming disaster, or they themselves are going back in time to avert a disaster. Things usually unfold from there. Typical permutations involve accidental time travel – to the past that disrupts the flow of history, or to the future to give a warning of things to come.
An emphasis on personal responsibility. Unlike many sci-fi stories, where science or crushing impersonal forces reduces mankind to a set of preprogrammed responses, the time travel story tends to focus on a person’s ability to make broad changes with just one or two little decisions. This, in turn, places an enormous burden on the person who can travel through time, to use that power in a constructive fashion. Or, at the very least, in some way that doesn’t cause reality warping paradoxes. Conflicts with people who want to use time travel in selfish or destructive ways can also come into play, particularly in a long running series about time travel.
What are the weaknesses of a time travel story? In short, they are confusing. Like, really, really confusing. Since time travel offers the ability for characters to go back and actively alter events that the audience has already experienced once it’s only natural that at least some readers will mix up what happened the first time and what the ‘altered’ state is. Heaven help the author who meddles with the same point in time multiple times. Add in temporal paradoxes, possible explanations of how time travel works in the first place, the Hitler Time Travel Exemption Act (along with any possible corollaries you can think of), the possibility that – well, you get the picture.
Writing a time travel story that your audience can follow, without insulting your intelligence or leaving some kind of glaring plot hole, is difficult. Not all who try succeed.
What are the strengths of a time travel story? First, it lets sci-fi do something it doesn’t always do well – let individual characters come shining through. Even with advanced technology, meticulous planning and the advantage of being able to check their work, time travelers still face a great deal of difficulty in changing the past. There’s enough room for conflict, but the potential for a single person or small but dedicated group to effect significant changes and see the outcome makes for very powerful story telling.
Also, it’s a very flexible medium, as I said before. Time travel can be used to tell just about any kind of story, from a romance to a spy thriller. It can be about exploration, saving the world from a disaster or fighting against crooks who exploit people via temporal manipulation. It’s scope is much broader than many genres in that respect.
Finally, there’s a wonderful quality to the idea that the past can be rewritten. The idea that the inadequacies that we face can be made up for, if a person would just have the power, the integrity and the compassion to find what went wrong and help us fix it. Everyone has at least one thing they wish they could do over. Sometimes the moral of the story is that the outcome we got was the one we needed, not the one we wanted. Sometimes the moral is that we need a helping hand. There’s a hundred shades of the possible between the two, and there’s nothing saying you can’t have both at once.
And in the end, that’s the beauty of time travel in a nut shell, isn’t it?