Time Travel Made Easy

I recently started 11/22/63 by Stephen King. The plot is a man is presented with a door that leads back in time and he goes through it in order to stop JFK from being assassinated. I’ll leave the critique of King for another time, but one thing that stood out to me was that he spends about 10-15 pages explaining the concept of “travel back in time to change the future” by way of "watershed event" and "butterfly effect". While the process of making those changes can be complicated and convoluted the idea that things in the past will affect the future is a pretty simple one. It’s no different than something in the present changing the future.

And then I realized that King actually puts a lot into this book to explain in unnecessarily long passages the most basic concepts of science fiction, concepts that should easily be picked up through the story. The huge data dump in the beginning of the novel shouldn’t be needed. And then I realized that King has made the same mistake that a lot of people make. He thinks time travel is complicated.

Time travel is simple.

Oops. I’ve let out the secret. But truly, the basics of time travel really aren’t that difficult. Sure, you can wind the narrative around obfuscation and overlapping trips, like in the wonderfully infuriating Primer, but the basics are always easy to grasp. Any storyteller that pretends otherwise is either trying to seem overly clever for dealing with it, doesn’t get it themselves, or thinks their audience is pretty dim. So here’s the breakdown.

The bottom most level of time travel is moving from one point in time to another but not in the usual way. We all deal with regular time travel which is into the future at the speed of one second every second. In H.G. Wells’ The Time Machine we get a really nice visual of someone sitting in a chair and watching time rewind as well as fast forward. The rate is changed. There are also instantaneous jumps in time travel fiction. That would be like Doctor Who, Back to the Future, Time Bandits… the list goes on quite a bit. Even King’s 11/22/63 has this. Step through a door and you’re decades in the past. Fast as that.

Where it gets a little more complicated is what kind of time the character is travel through. But don’t worry, it’s still a much simpler concept than most people expect. A lot of time different versions of time are rationalized or justified with technobable but that’s like putting fancy clothes on a mannequin. The model underneath is almost always eerily simple and usually one of three choices. With mannequins it’s man, woman or child. With time I’ve named the three fundamental forms solid, liquid and gas.

• Solid – Time is completely unchanging. If you go back in time and do something then you were there before and that action has already happened. Time travel is a closed loop. There is no free will, everything is predetermined. Or at least determined the first time events occur.
• If you travel back and step on an early amphibian then that animal had already died in the past.
• Examples
• Time Traveler’s Wife
• Harry Potter and the Prisoner of Azkaban
• Bill & Ted's Excellent Adventure - Since they come back to the present and nothing noticeable has changed we know that it is either a solid or liquid timeline. Small details, like their time loop escape from the jail cell seems to suggest a solid timeline.
• Liquid – Events can be changed but small changes will get passed over. You can visit and things won’t change but if you make a large change then it will affect the future.
• If you travel back and step on an early amphibian then another will end up evolving to eventually fill a similar role in history.
• Examples
• Quantum Leap
• Back to the Future
• Gas – Every little thing a future visitor does in the past will have consequences in the future. This is the scenario where the butterfly effect is often brought up.
• If you travel back and step on an early amphibian then perhaps you will return to a future of intelligent sea life. Or there will be no life at all.
• Examples
• A Sound of Thunder by Ray Bradbury
• Time and Punishment, the Simpsons parody of the above short story
• Uncertain
• Doctor Who - The very definition of inconsistency for the sake of a story. This universe seems to vacillate between 
• Primer - Evidently a malleable timeline though the range is so short it's impossible to tell the extent of changes to the future.
• Star Trek
• Solid or liquid. The novelization of Star Trek IV: The Voyage Home (the one with the whales) suggests a solid universe as the employee Scott gives the formula for transparent aluminium to is the historically credited inventor.
  HOWEVER! The new Star Trek begins with an event that branches the timeline so the new Trek movies take place in a changeable timeline. Since the crew still gets together I'm going to call it as liquid.

And that is the basic gist of time travel. Once you figure out the material of time then the events should just fit into the template. Of course, some fictional universe will change their physics. The Terminator universe is notorious for this. The first movie is a solid (possibly). Kyle Reese seems to always be John Connor’s father. His trip back and sleeping the Sara Connor is part of repeating events. Terminator 2 seems to be a liquid universe since large changes are made (blowing up Cyberdyne) and that gets things changed in the future (avoiding the robot uprising). Terminator 3 tries to pretend they are the same form of time and end up with a soft solid, something like rubber. Events can be pulled and bent but the main points are always there. The war always starts, the robots always revolt. The TV series The Sarah Connor Chronicles can actually be somewhere along the liquid/gas rules. Small changes in the past are seen to make small changes in the future. Since the timeline isn’t very long long it’s impossible to tell how soft their version of time is, but changes can be made.

That's your time travel cheat sheet. The type of time that a story deals with is infinitely more important with the mechanism. Travel may be achieved by a magical trinket, a medical condition or a machine but as long as you know the timeline is solid then it's not that confusing.  A writer can justify time travel with as convoluted a device as they want. Primer uses a mysterious effect of cold temperature physics. Planet of the Apes used relativistic effects in a fast moving space capsule. Back to the Future has a car with little to no technical explanation. And while each of those mechanisms helps with building atmosphere and style it's not necessary to understand the inventions to still understand the world. Do not let talk of quantum physics or dozens of pages detailing the definition of "watershed event" or "butterfly effect" scare you. Just see what time does and it'll all work out in the end.

Or go horribly wrong and destroy the world you know.

• The "Not Actually Time Travel" bonus list
• Terra Nova and Michael Crichton's Timeline - Both of these are actually alternate universes. While stories like Back to the Future play with branching timelines these two stories involve parallel earths that already exist and just run next to ours. Calling these time travel is like saying that going to Canada puts you 10 years in the USA's past. While it may look similar it's not true.
• A Christmas Carol - This is more akin to astral viewing. The "travel" is hazy and even the future  vision is yet to happen so it's not much of a trip.