WTF? Time Travel For Dummies and Earth People

[Oliviarfrias]

For the past year or so, I've been doing a re-watch of every prime timeline movie and episode of Star Trek in Stardate order. I'm currently in the Voyager/ DS9 era. While I'm a die hard Trekkie, something that absolutely drives me bonkers is how inconsistently the franchise portrays time travel. Sometimes things you do in the past can affect the future, other times the future is fated to happen no matter what you do, and still other times changing the past creates an alternate timeline. It's all over the place. 

To prevent more mistakes like this, I have provided a handy guide to the three most common types of time travel logic and how they should be written to provide narrative consistency.

 

Model 1: The Butterfly Effect

What It Is: The most common time travel model shown both on screen and on the page, but also the one gotten most woefully wrong, the butterfly effect theory of time travel basically states that small changes in the past can have a dramatic effect on the future.

How Not To Do It: Don't lose sight of logical cause and effect. If you're skipping back and forth between the past and the future, make sure the future you are portraying is a logical extension of the past with those changes. For example in Looper, as much fun as it is to see Seth lose his body parts in real time as he desperately tries to make it to the door to save himself, it makes no sense. How would he have walked to the door in the first place if he didn't have feet?

How To Do It: First of all, you need to either make sure the changes to the timeline affect your protagonist realistically or you need to explain how they are isolated from those changes to avoid a Looper-like scenario. The first scenario is tricky. The only book I can think of that does it well is This is How You Lose the Time War Amal El-Mohtar and Max Gladstone, in which Agents Red and Blue have to manipulate time to make sure not only does their side win, but that they can even exist in the present. But the feel and logic of that book is surreal and dreamlike -- not something that can be easily reproduced. The second scenario is a bit easier.

Though I earlier stated Star Trek can be a mess when it comes to time travel, one good example is in the Star Trek: Voyager episode, "Year of Hell," where a species creates a ship that exists outside of time and has the power to erase things from ever existing. In trying to use the ship to destroy their enemies, they unintentionally wipe out his entire civilization. This episode also does one other thing right, in that it shows how sweeping these changes can be. For example, at one point Chakotay ponders erasing a comet from existence, only to discover that comet spreads the seeds of life to hundreds of civilizations. So destroying the comet would destroy all those civilizations. Does the ship outside of time require some suspension of disbelief? Sure. But it lets the episode be what good sci-fi should be, which is a thought experience.

 

Model 2: The Self-Fulfilling Prophecy

What It Is: This is the idea that the main characters going back in time were always part of the past -- basically embracing the idea of determinism in the universe.

How Not To Do It: Don't get the circular timeline mixed up with circular logic. As mind-blowingly beautiful as the "tesseract" scene in Interstellar is, it leaves a lot to be desired in terms of narrative logic. We are supposed to believe future Cooper created the tesseract for present day Cooper so he could save himself by interacting with his daughter in the past. This makes no sense, as it implies future Cooper has knowledge that he was only able to get because past Cooper had survived…which he wouldn't have been able to do without the help of Future Cooper. Basically the problem here is that even with time travel the events couldn't have unfolded as presented because it involved the protagonist having knowledge of events that wouldn't have happened if they hadn't had the knowledge.

How To Do It: As silly as it is, Bill and Ted's Excellent Adventure actually does an okay job of keeping the timeline sensible. While they don't completely avoid the circular logic trap, it is presented in a more linear fashion that at least lets the viewer follow along. For example, when we see Bill and Ted step out of the booth to convince their earlier selves that Rufus is trustworthy, we know only what they know at the time. At no point does the story ask us to step outside the linear experience of Bill and Ted, so it doesn't force us to question things the way Interstellar does. Furthermore, it never has Bill and Ted do things that don't make sense given their current knowledge. Another option for this kind of storytelling if you're writing in a tone that can't afford to be hand wavey is to use a being that exists outside of linear time. If you do that you can have a character that responds to things "out of order" without causing a circular logic breakdown. An effective use of this technique is Dr. Manhattan in the Watchmen franchise, or Rose Salazar in the animated series Undone.

Model 3: The Multiverse of Madness

What It Is: Every time something changes, a new timeline is created, creating an ever-expanding multiverse.

How Not To Do It: Don't get it mixed up with other models! This is honestly the easiest model to keep consistent if you stick to it. One of my least favorite scenes in an otherwise solid time travel movie, Avenger's: Endgame, is when Steve Rogers appears as an old man to pass on his shield to Sam Wilson. Why? Because up until that point the film had portrayed time travel as entering alternate timelines. So theoretically when Steve went back to be with Agent Carter, he was entering an alternate universe and thus should not have existed as an old man in the prime timeline.

How To Do It: Going back to the Marvel Cinematic Universe, it's hard to beat Loki for alternate timeline fun. Although it has its logic flaws (for example, "What changes to the timeline make Loki an alligator?"), the Time Variance Authority (TVA) is a unique take on the multiple timelines approach. 

To sum things up, time travel is a tricky thing to write sensibly, given that our understanding of cause and effect is based on a linear existence. Still, I hope this guide helps you write your time travel in a way that helps your reader stop focusing on the logistics of the time travel mechanics and focus on what matters…the story you're trying to tell.