My son, Ethan, posted a neat graphic by Harrison Densmore explaining three approaches to time travel in stories. It’s pretty good, actually. Check it out:
I think this is a great start, but it’s incomplete. There are at least six approaches to past time travel stories. Note that future time travel isn’t such a big deal: we do it all the time, and even know how to speed it up (travel at relativistic speeds).
Here’s the list I know.
- Time travel is impossible. The reason I mention this as one of the options is that a story can be about people attempting time travel, thinking something is time travel that actually isn’t, etc. I wouldn’t be surprised if this turns out to be the real one.
- The self-healing timeline. In this one, you travel back in time and change something, but the universe changes something else to cancel your change out. I’m not a fan of this one, because 1) why does the universe care?, and 2) two changes that cancel out one particular effect are not the same as not changing anything in the first place. For instance, what about the people whose lives would have been affected by the orphan?
- The timeline that’s smarter than you. This is the one Densmore calls “The Fixed Timeline.” In this one, any changes you make were what happened all along; you just didn’t realize it. Maybe you shot and killed your grandfather, and it turns out that wasn’t your grandfather at all, that’s just what grandma told your dad when he was growing up. I’m not crazy about this approach either, because it requires existence of some kind of intelligent Fate and imposes arbitrary limits on human intelligence. Humans may be intellectually limited, but we’re not stupid. Except sometimes, but that’s another discussion.
- Dynamic timeline. Densmore covers this one nicely. I think nature abhors a paradox, but you can still get fun stories out of this.
- Multiverse. This is the easiest one to work with, although I’d point out that some multiverse stories don’t restrict universe-hopping–so you might spawn a new version of the universe and experience it as long as you stay there, but be able to come back to your original timeline because your machine or magical ability or what have you is just that good.
- The elastic timeline. In this timeline, you can go back in time and do whatever you want, and the world will change accordingly (e.g., no baby Hitler), but when you return to your original time, nothing will have changed. In this approach, the universe is assumed to have some kind of resilience, or time travel to occur in some kind of pocket universe that vanishes when you leave it. I have an unfinished story that uses this approach in which a young man regularly travels back in time to kick the living crap out of horrible dictators from the past–just appears in Francisco Franco’s bedroom, for instance, and goes to town on him with steel-toed boots. As you can imagine, he comes to find this approach to happiness flawed.
Oh, a pro tip if you travel back in time to the Middle Ages in Europe: bring pepper. Most valuable spice of the age, black peppercorns. Just hit Costco before you go and buy yourself a fiefdom–or end up dead by the road when they rob you, but nobody said time travel was safe. Actually, that’s a unifying feature of every one of the time travel approaches mentioned above: none of them is particularly concerned with what happens to you.
Another subgenre that works like a time travel story in some ways is the Alternate Universe story, like Harry Turtledove’s The Guns of the South, in which twenty-first century white supremacists travel back to the American South and supply the Confederates with AK-47s. The Man in the High Castle is another fascinating example of this genre. I find these fascinating, though they can’t be easy to write. One of the reasons I mention them with time travel approaches is that sometimes alternate history stories are conceptually time travel stories (as in the Turtledove example)–which includes times when you might think you’re just looking at an alternate history but (twist!) there turns out to be time travel involved. I’m guessing that might be how The Man in the High Castle works, but nobody ruin it for me, OK?
In the shameless self-promotion department, I have some 11 very short time travel and alternate universe stories in my Bam: 172 Hellaciously Short Stories (of things that could never happen), which you can get on Amazon in paperback or eBook format.
So … what did I miss?