The Fox has had to listen to me rant and put up whiteboard diagrams about time travel in movies enough that I feel it is about time (get it?) that I subject the rest of you to my madness.
In my Avengers Endgame Spoiler I brought up Back to the Future with a caveat that you have to ignore the picture changing and Marty slowly fading for the time travel to make sense. And Eli, of Frozen Ground review fame, rightly called me out on that this was cheating the story.
In the Back to the Future series the screenwriters want you to feel good about the movie. Marty not only saved his parent’s marriage he made it better. He went to the future and saved his grandchild. He saved his friend from the past. Sure, this is fun and makes the audience feel good.
But here is the problem: Rules matter. Story matters. Consequence matters. And when time travel is involved writers are tempted to treat it like science fiction or fantasy fluff. The time travel is merely a device to move the plot in an interesting way. But whatever master the time travel story is trying to serve, it is ultimately a mystery at heart. You know where the story has to go, so how does it get there?
And to add to Hollywood’s dilemma, a time travel movie is also a prequel. And if Hollywood has show us anything. It is they are horrible at prequels.
[Rules, where we are going we don’t need rules]
Solving for the Observer Paradox is the key that any system of time travel must work around. A Paradox, in its simple form, is a self-contradictory logic statement; it seemingly cannot be true or false.
For a logic example, “This sentence is a lie”. For a time travel example, going back in time and shooting your younger self.
As we are telling our story, the protagonist is the observer which must not fall victim to a time travel paradox. It’s why I have a call out for the photo/fading in Back to the Future. Either the observer is unaffected, or they are instantly affected.
The Three Main Flavors of Time Travel
For the first two flavors keep this phrase in mind.
Everything that is going to happen has already happened.
This is the easiest version of time travel to write because changing the past does not matter. You have entered a new timeline, you are not changing your future but are instead becoming part of the timeline you have entered.
And you aren’t changing the future of the new universe, in that universe you always arrived and did everything you were going to do.
As a storyteller you now have two options. Does your observer travel exactly back to where they left their own pasts future unchanged, this was the Avengers Endgame gambit. Or do they continue forward from their new timeline as in Sliders, possibly Quantum Leap, and as I *Prefer* to think of it, Back to the Future.
Whether you take your observer back or continue forward keep in mind that you have changed nothing because as noted above; Everything that is going to happen has already happened.
In Back to the Future when Marty returns from 1955 he meets Biff, who says, “I thought you were up at the lake with Jennifer.” He is, the Marty from that timeline is up at the Lake with Jennifer and there are now two Martys in this timeline/universe. In the universe Marty left from originally, he never makes it home. From that timeline’s point of view Marty went to see Doc one night and never came back.
Multiverse Lightning Round:
Back to the Future
Continuum (TV Series)
Fixed Time/String Time
Take a string end to end and ball it up. Create as many knots as you wish; go to town making an absolute mess of things. Now to go one end of the string and follow it, through all of the convolutions, to the end. You just experienced time travel without paradox.
This is the hardest version of time travel. As modern cinema has taught us, Hollywood despises consequence. I’ll point at Fantastic Beasts: And where to find them, as my example. In this movie they released the Thunderbird at the end which through it’s ambiguous power erased the memory of everyone in New York so they could ignore that a giant smoke monster just had a rampage.
Cool… great….. Except….
Everyone in those buildings that were destroyed, and you showed us them putting the buildings back together, is still dead. People that were driving when they suddenly became catatonic from the Thunderbird, likely got into some accident. You went out of your way to show us people in the shower to show how the ran could affect people indoors, except that is not how water filtration plants work not does it cover anyone inside who was unaffected by the Thunderbird tainted water. In other words, it was shit.
And we are back from the tangent. In fixed time everything matters because you have to end exactly where you began. Or at least allow what you know is going to happen to happen if your story ends before that point.
The example the world wants to offer up here is Primer but honestly, it’s a bit of a bad movie. The version I watched had bad sound and the story is convoluted by design. Instead I offer up Time Crimes (Los Cronocrímenes). Just a spectacular example of fixed time in action. If you demand an English version, 12 Monkeys offers an example of how you can both subvert and fulfill the demands of fixed time though the mechanics are central to the plot and could leave the door open for confusion.
The important Take Away from fixed time is “There is no paradox because everything that is going to happen has already happened. You cannot change the past because you didn’t change the past.”
And I understand why both people and Hollywood are not fans of fixed time. Time travel is a wish fulfillment trope and the concept of “You cannot fix your mistakes” is anathema to both groups. Sorry.
Fixed Time Lightning Round:
Harry Potter and the Prisoner of Azkaban
Bill & Teds Excellent Adventure (Yes, this)
Predestination (The story it is based on, don’t quote me on the movie)
Game of Thrones (Hodor)
Ripple Time: AKA, the most nebulous of time travel.
This is the Have your Cake and Eat it Too of time travel. A stone is dropped in the past and ripples forward as time progresses.
In this version the future is mutable but the observer who is in the now-present is protected from instant change but still subject to progressive change.
A wonderful example is the movie Looper where we see Bruce Willis suffering from the effects of memory change as he is present for the alterations of his own history.
This form of time travel still leaves up to the author the decision of how to handle the departure point. If Bruce Willis had survived long enough for the present to reach the point he would have traveled from then what would happen to his character? So far there is no example of this happening in cinema. Instead we often see the more terrifying version of Ripple Time.
Hot Tub Time Machine (but also Days of Future Past). In Hot Tub Time Machine and Days of Future Past both our heroes traveled back into earlier versions of themselves. After some adventures they traveled back into their now present selves. During their transit home the changes they had wrought in the past were manifest at their original present. Cool, this is ripple time in action.
Except…. The past self you had traveled from actually lived those 30 years. They had adventures and mishaps, they fell in love, had children. learned, laughed and achieved. And then you arrived from your past transit and KILL THAT VERSION OF YOURSELF. You are now an imposter in that often better version of you’s life. You don’t know what your job is, you don’t know your address, the school you graduated from, or even the names of your children. You might be married to a stranger. It is terrifying and it is only through the lack-of-consequence style of storytelling that Hollywood has embraced that this is considered a happy ending.
Ripple Time Lightning Round
Hot Tub Time Machine
X-Men: Days of Futures Past
Most TV shows with a time travel episode
Bonus Round: Determined Time
This is a special case of Time Travel where an outside force, either the director externally, or fate internally desire a particular outcome and that desire will manifest in the story.
In Back to the Future as presented the audience is shown a photo of of Marty and his siblings that ebbs and flows as a sort of score card on how Marty is doing in the past. Except due to the Butterfly effect there is an absolute 0% chance you could change anything in your parents past and still be born. You are already a 1 in 150 Million chance baby as is, if your parents conceived 1 microsecond latter a different sperm in that 150 Million made it to the egg and you are a different baby. The resulting YOU may be remarkably similar owing to Nurture, but you will be genetically different.
So for the Back to the Future story to play out as presented then there is a force in the universe that would create a version of Marty in the new timeline as similar to OG Marty as nature would not do so.
A more direct version of this is the 2002 version of The Time Machine. In this movie the protagonist invents a time machine to prevent his fiance from being killed. But no matter how often he travels back and no matter that steps or precautions he takes she always dies; as if pre-ordained.
This style is…. fine, it’s fine. The problem is that it implies a guiding hand of fate and this mechanic will steal agency from your characters.
I’m just some guy on the internet. Do what you want. But rules matter, and story matters. And if you want to tell a good, tight story then try to understand not only the most basic elements of your time travel story but also the far reaching consequences of your chosen methodology and treat them and your audience with respect.