I Spent My Lunch Break Thinking About Time Travel
Time travel is a difficult subject to think about. No one has any proof that it’s possible, but no one has any proof that it’s impossible either. Many theories are based or debunked on the conclusion that if time travel were possible then we’d be swamped with “time tourists”. That we don’t see people running around on hoverboards taking pictures with their holographic cameras means that time travel doesn’t exist, obviously, but then again, no one goes on vacation and screams in the middle of a crowd that they’re from Boise, either.
But what if time travelers were here, but not only do we in the present not realize it, but they themselves don’t realize it?
The theories of time travel tend to work backward from the idea that time travel is entirely possible. From there, we consider potentially visible signs that the timeline was messed with: we suddenly meet ourselves, or the universe violently tries to correct the modification in the timeline such that weird things happen that the rest of us can’t explain…typical exciting sci-fi stuff that makes for great stories, but which has little evidence in the real world. Basically, when a problem with the theory arises, theologians try and work out a deus ex machina as to why we haven’t seen the ramifications of time travel. Does a lack of hard evidence actually prove that time travel is or isn’t possible? No, but it’s fun to come up with all of these ideas.
One of my personal favorites is the concept where we have not just a single timeline, but an infinite amount where all options in the decisions that we encounter in our lives were made. This is hand-waving of the highest order because it means that everything that could happen, has happened…just not where or in a way we can see it. In a universe like this (a multiverse, actually) timelines split like branches from a tree trunk, and they keep on splitting until they reach a potential end of time itself.
In order for us to accept this, then, we need to accept that everything that will happen has already happened. Here, life is more of a YouTube video (complete with a comments section) in that there’s a beginning, a seemingly infinite middle, and an eventual end, but it’s not live; it’s pre-recorded. I know this is hard for the up-with-people crowd to accept because it means that our decisions really don’t matter and that we’re only carried along the currents of our timeline. This is another case of “if it were true, would we even know?” so I’m not so concerned with the question of free will as I am considering it as a viable possibility.
From this point on, let’s talk about Timeline A and Timeline B.
At some point, both A and B were the same timeline which diverged due to some event which was significant enough to change circumstances and affect the future*. For our purposes, let’s work on the following assumption:
| Timeline A
You and a passenger are driving in your car. At an intersection, you turn right and arrive at your intended destination without incident.
| Timeline B
You and a passenger are driving in your car. At an intersection, you turn left and are later involved in a collision which kills your passenger and leaves you disabled for life.
The divergence was always going to happen because in an infinite multiverse there’s no reason not to have timelines which include cases where you turn left and where you turn right. And because everyone’s personal timelines intersect, there’s a specific line out there where your turning decision, coupled with someone else’s decision (whatever it was) literally collide and cause tragedy. Of course, there’s also a timeline where turning left leads to the same place as having turned right, both without incident, but we’ll get to that later.
It stands to reason that if you from Timeline B could go back in time, you would certainly want to correct the events that lead to the death of your friend and the disabling of yourself, right?
Would that even be possible? Based on how I was thinking about it, no.
Here’s where I might need a flowchart. Each timeline has already happened from start to finish. That means that neither timeline can be without a “you” in it because that’s the way the cosmic script has been written. Since the person from Timeline B is heading back to convince him or herself to take a right instead of a left, that means that you have traveled back in time specifically to make a different choice. In effect, you have already started to alter the timeline the minute you made up your mind to do this thing. The desired outcome of traveling back in time, then, is to find your Timeline B self whole again, and your friend alive by dissuading your earlier self from making the decision that caused the calamity.
In order for you to make this decision and to know that you’re actually making a decision, you need to experience that “better” timeline from the point where you took the “better” turn, until the day you die, and you need be able to know the difference between the two timelines. But in order for you to go back in time to convince yourself to take the alternate route, you need to have existed in a timeline where the collision happened. Essentially, you still need to exist in two different timelines, even though Timeline B version of you wants to “hijack” Timeline A’s outcome — which is Timeline A itself in its entirety.
What this means, then, is that as soon as you made the decision to go back and take the right turn, your self which originally took the right turn has now taken the left turn. If you want to think about that some more, you’ve doomed another copy of you to the tragedy you’re trying to correct, but because the you that traveled backwards in time has now taken the right turn and not the left, you the traveler are no longer injured and your friend is alive in the timeline you occupy. You are now living in Timeline A as it was originally written, and your other self is banished to Timeline B as it was originally written.
The real kicker is that neither of you knows any different. While you might have enacted the time travel to go back to the point where you made a different decision, that decision had already been made by you. In short, you’ve done absolutely nothing, and even if you did, you wouldn’t know because you are now part of the pre-written narrative in this other timeline.
There is one way to get around this, which makes this fiction even more fictional. If you could somehow tether yourself to your original timeline, then no matter which alternate slice you occupy, you would understand that you came from different circumstances and would be aware of the outcome of all decisions that you have a part in making, from the point at which you entered until the time you — the you that traveled back in time — die.
I realized that this is a good way to explain the time travel in Travelers, to some extent. They don’t travel back in time physically, but there is apparently some tether from the 21st century back to their “home” century. We see this at the end of the series when Grace “fixes” Marcy by re-downloading her consciousness from the future. She references “quantum entanglement” which alludes to the idea that the original bodies of the travelers might still be alive in their version of the future, despite the fact that they have changed the future into one they do not recognize. In this case, two travelers — one from the “original” future, and one from the “revised” future — both have memories of different futures where their individual bodies and/or consciousness exist.
But back to an earlier point: what if circumstances prevailed that allowed you to take both a left and a right and arrive at your destination unscathed? Is that significant? I submit that yes, it’s very significant because it’s something we can and do experience from time to time. We’ve given it a name, too: deja vu.
Because our 21st century is happening some point after the start and before the end of the universal timeline, we’ve got a whole lot of branches behind us, events where something happened to split a single timeline into many branches. Although it’s uncommon, it’s not impossible for different branches of a tree to meet as they grow and fuse together, so it stands to reason that maybe the Universe, in an effort to conserve energy or something, finds points in different timelines where branches can be remerged into a single timeline. As an object oriented developer, this is a bedrock pattern: don’t keep rewriting the same code. Instead, centralize it once so we can refer to it whenever we need it. That way, we cut down on work being done, and when we need to make a change, we make it in one location and it takes effect everywhere.
Of course, nothing is ever simple and sometimes despite this centralized code we need to make little tweaks that lead to what we call “overloading”. When we overload a block of code, we create two extremely similar blocks of code which have just a slight variation. Both have a use, and both do roughly the same thing, but pound for pound they don’t quite mirror one another.
Deja vu, then, is what happens when two timelines merge but force us to deal with the consequences of arriving at the same point by different means. This leads to a reality that’s otherwise unremarkable — except for the feeling that something is out of sync. We generally consider deja vu to be a case of “this has happened before”, which could be a result of the same events happening with just a slight variation, or when we feel that something is about to happen, but it doesn’t.
Of course, deja vu could also happen when we suddenly realize that we exist in two different timelines and are experiencing the same content at a fractionally different speed. The merging can still be considered to be in effect, but now we are each a duality and are seeing the same event from different timelines.
I’m sure that there’s a whole lot of holes in this idea. I’m not a physicist of any kind, and I really only came up with this during my lunch hour (literally). Thinking about time travel is both fun and frustrating, and as an academic exercise, it’s certainly one of the better ones out there.
* Really, if time is predestined, then there’s no “changing the future”. Divergence is merely a point at which we can identify where timelines split, but which otherwise have no active effect on whether something did or will happen in the future — everything has already happened.