The Grandfather Paradox: Playing the Strings in Your Time Travel Story
So, you want to write a nifty little piece about travel backward through time. It's been done in all the major Sci-fi franchises…. And yet… you want to be the one "to do it right". After all, you've always been bothered about that problem that doesn't quite get addressed...
You know the one I'm talking about…
That's right: The Time Paradox, or how it is sometimes known, "The Grandfather Paradox".
Here's the problem: Every show, story, movie, whatever, that has a time travel sequence, warns about one thing:
"Do not do anything that will mess up the timeline."
What happens if you mess with the timeline? Well, any number of things could happen but basically it can be summed up with "What if you went back in time and killed your grandfather?" This would be bad because then you would not exist.
You see the problem right? I mean besides the whole you killed your Grandfather thing...
That's right: How would you have gone back in time to kill him in the first place if you had gone back in time and killed him and then didn't exist as a result?
Yeh… don't think about it too long….
Ok, so this seems pretty straight forward: You cannot go back in time because anything you would do, including just showing up I might add, could catastrophically alter the timeline… leading to the fact that you wouldn't have gone back in time in the first place…
Oh yeh, its bad isn't it?
So, let's leave that for now and move on to the explanation.
We begin with Einstein and the Theory of Relativity. Now, before your eyes glaze over, I am not about to give you a physics lesson. I am just going to say this: The Theory of Relativity allows for time travel. I did not make this up, it is true. But the theory holds that time travel can only go one way- forward. So Einstein's theory says that we can go into the future. Why not back? Well… that would be that time paradox thing that I told you not to think about right now, so don't think about that right now.
So physics says it is theoretically possible to go forward in time, but not backward…. Or does it?
You see in recent years some physicists have come up with new theories… some pretty wild theories. Wild if you are not a sci-fi fan of course. Because if you are a sci-fi fan, you are well acquainted with what these physicist are saying. This is where physics, philosophy, religion and science fiction sort of get blurred.
And you thought The Grandfather Paradox was complicated…
It's called String Theory. Ok, now I will not pretend that I understand all the physics jargon, because I don't. String Theory says a lot of things about quantum mechanics, but the most important thing it says, as far as you, the sci-fi writer is concerned, is that there are alternate universes.
You heard me, alternate universes.
The theory holds that for every action there are splits, "strings" that form their own little universes. Some of these are very similar to the one we are sitting in right now. Some are very different. We've all the played the game "What if I had…" in our heads. Well, if this theory, and other theories about alternate universes, is correct, you actually did do whatever it was you wonder about.
Pretty trippy huh?
I know. You took a moment and pondered that and thought about how neat it would be… or how scary it would be… and now you are ready to….
Entirely reject it.
It cannot possibly be true… right? Do you KNOW how many universes that would be? EVERY ACTION? Come on!
And yet, philosophy often ponders the reality of this reality. As does religion, as does science fiction, and as does science. Is what we see real? Are we who and what we think we are? What happens when this "life" is over? Is there another and if there is, is it simply another universe?
But that's not what we are here to talk about. Because now is the time to think about that thing I told you not to think about.
The Grandfather paradox. Yes, this is all about how to solve that problem. You see, if you go back in time, who says you went to YOUR timeline's past? The past could be an alternate reality and so killing your grandfather for whatever reason you would do such a thing, in an alternate reality would have no effect on you in your reality.
Look, I said I had a solution, I didn't say it wouldn't be confusing.
Coming back of course, you would never really know if you were in your reality. What if you came back into a reality caused by the fact that you spilled your coffee that morning, when in your reality you didn't?
This would of course create another paradox.
Damn it.
Yeh, well, figure this one out on your own…