Time travel wrinkles my brain. How’s that for a topic sentence?
It’s a favourite device in science fiction (and fantasy) because let’s face it, if you had the opportunity to traverse history, would you turn it down? Haven’t you always wanted to wander around your favourite past era, sit in on a world-changing event, or go the other way and see what the world will be like in 300 years when the apocalypse has hit or whether or not you get married and end up having a little Jetsons-esque family?
Time travel can create endless fun and endless stories (how do you think Doctor Who’s managed to stay on air for 50 years? All of time and space = literally endless plot possibilities) but like most super fun high-tech things it comes with a long and arduous warning label and a set of curly rules. It doesn’t help that these seem to differ depending on the method used and the story it’s used within. For example, one story world may deem travelling to the past completely fine since it’s all already happened and time is fixed in a straight line, and some may warn against it with giant flashing lights because simply by setting foot in an era you haven’t yet been born into, you’ve altered history as we know it.
When traversing the time streams one must be dutiful not to step on any butterflies, alter any significant moments in history or, say, get hit by a car and prevent one’s own parents from meeting thus erasing your own existence. This should all be fairly straight forward, but it’s surprising how often heroes manage to screw it up. What then? Well, maybe you could go back in time again and stop yourself from messing up…
This is where things get mind-curling. More often than not it’s very easy to end up with more than one version of your intrepid time traveller in the same place, be it older or younger versions of themselves walking around together, or the version of them from the previous time they travelled back in time, or an evil time-twin conjured by the warping of time streams. Or, you could bypass that altogether and simply set down in rules that every time someone time travels they don’t overlap, merely create an alternate universe where the events they disrupted unfolded as they did.
Either way you slice it, messing with time creates a whole lot of hairy problems. Even if the righting of history is something localised, like in the aforementioned Back to the Future, it still carries enormous ramifications. In that movie, the main character travels back to the 1950s and has to set out on a quest to make sure the teenagers who will become his parents get together, thus ensuring his continued existence. But our friend Marty doesn’t just play with that, but a whole bunch of other things, including, apparently, the invention of rock and roll and the rise of African-Americans to political power. Marty also convinces a man to invent time travel so, in the future, he can invent time travel to send Marty back in time to convince him to invent time travel…
And here we start getting these bizarre, mind-bending loops appearing. Such as in The Time Machine, where the hero invents (spoiler alert) a time machine to travel to the past and prevent his wife from dying. However, this is doomed not to work because if she hadn’t died, he wouldn’t have invented the time machine in the first place, thus creating a paradox. It also brings up the question of if he had succeeded, would things simply have reset and when he travelled back to the present (just not as catchy as a movie title, is it?), the new present with his wifey still alive, would he simply have forgotten the whole ordeal of her death and his subsequent time traversing because in this new timeline it never happened?
Then there’s Looper, which as well as jarringly fashioning the first half of itself into a Film Noir detective story and making us believe that Joseph Gordon-Levitt could grow up to be Bruce Willis, also made a comment of the cyclical nature of destruction. Older!Joe is shot back in time with the mind to kill the kid who grows up to be the crime boss who kills his wife, while Younger!Joe runs around trying to stop him. What Younger!Joe realises by the end of the movie is that Bruce Willis showing up and trying to kill the mini mob boss is what traumatises the kid into turning evil and growing up with a violent vendetta against the Loopers in the first place.
The same thing happens in the first Terminator movie—the father of the man the time travellers are trying to save turns out to be one of the time travellers, and if they hadn’t jumped into the past and into bed with Sarah Connor there would be no revolution to save in the future. Fry does the same thing in Futurama, becoming his own grandfather and prompting cries of “Screw history” from the rest of the disgruntled crew.
These plot types can be fun because, especially when the characters drop in on significant events in history, or things foreshadowed in the story, the viewers at home can revel in their realisation of “Oh it was you!” Like in the good old days of New Who, when Rose remembers her mum telling her about a mysterious woman who stayed by her father’s side as he was dying… it turns out the mysterious woman was Rose, who travelled back to see him off (while, of course, first trying to save him and proving that you shouldn’t alter fixed events… despite the fact that the Doctor and company have been treading on history for most of it).
On the subject of Doctor Who, which bounces around time and space willy-nilly, they played with the concept of “fixed points in time”. The Doctor being killed at this particular place was a fixed point, and if this event was prevented time would crack or warp, or something. As I have said, I’ve not actually been keeping up with it, but the point is that the outcome would be bad. This was, of course, somehow allowed not to happen because well, Matt Smith is still bounding around our TV screens isn’t he? And the audience knew in their hearts that that would have to be the case, because not even Moffat would kill off the titular character mid-season. So that left them guessing how this “fixed point in time” would be evaded.
The problem is, how on earth was the audience meant to guess when the rules of the situation had been completely made up, loopholes and all? It creates drama, yes, but if your viewers are entirely out of their depth you can’t exactly tease them with trying to figure out what the twist is going to be.
The form of time travel I’ve seen that allows for the most sense to be made is the Groundhog Day version, one person pressing rewind on time rather than physically moving around in it. The main character of the aforementioned movie has to live through the same day over and over again, allowing him to not only live like there’s no tomorrow but to know exactly what is going to happen at any given point.
This is also the method used in The Girl Who Leapt Through Time, where the heroine flings herself backwards in her personal timeline and allows herself to relive and redo moments in her daily life. It’s a power I sure know I’d abuse and have fun with. It’s much more linear and understandable as a form of time traversing, however as Madoka Magica demonstrates it still creates alternate universes/timelines every time the person holding the clock cranks it back, which will severely mess up your business. It also still comes with the problem of trying to alter points in time or achieve certain outcomes, be it saving someone’s life (or, in the case of Supernatural, trying, failing and watching your brother die in a million different and amusing ways) or trying to get laid. Or both!
If you’re too pedantic and trigger-happy with that time turner, you may get stuck in an endless loop. But hey, it can’t be that big a deal. Hermione Granger got given a timestream-altering device as a twelve year old, and used it to take two classes on the same line. I mean, I’ve been tempted in my height of nerdery, but not so severely that I’d mess with time itself. And if the Ministry of Magic is handing those things out to students, who else can get their hands on them?
As Looper’s surly narration denotes, as soon as time travel is invented it’s made very, very illegal. And quite frankly I can see why, if only to prevent the law enforcement in the future from getting serious logic headaches.