Hello, travellers, and welcome to Recorded Tomorrow, the show where we break down the rules & pitfalls of using time travel in fiction & games. Jonathan is caught in a temporal rift, so I’ll be navigating the timestream solo today.

Rather than try to tackle a deep dive by myself, I thought I’d take this opportunity to recap the lessons we’ve covered so far, & consolidate them all in one place. I’ll go over the rules we’ve established & define all the terms we’ve used. I’ll jump around a bit, but hopefully I’ll do it in a way that makes sense. Right, let’s get straight to it:

A traveler isn’t necessarily a person, but refers to anything that’s being sent through time. That could mean a person, or their consciousness, a device, even just information. We might sometimes refer to this as the subject.

The origin is the time and place from which the traveler departs, and the destination is the time & place when they arrive.

Now let’s talk theories: Variable Thread is typically a single, mutable timeline of continuity that can be altered using time travel. In fiction that uses variable thread, as soon as someone or something travels to the past, the timeline resets from the point of arrival, and the original timeline ceases to exist. This is the most common style of explicit time travel. Think Back to the Future or The Sound of Thunder. These types of stories are usually a regret metaphor.

Fixed Thread is an immutable timeline, where the continuity can’t be changed, even by traveling back in time. Any actions taken by a traveler happened before they traveled, the only thing that changes is the perspective. This is your Bill & Ted, your 12 Monkeys, your Prisoner of Azkaban. These stories are generally about trying to be in multiple places at once, taking on too much, and learning to prioritize. 

Lastly, we have Multiverse time travel. This theory involves multiple, timelines, and can come in a couple of forms: in Michael Creighton’s Timeline, the characters don’t actually travel forward or backward in time, but rather laterally into older or younger universes; In Avengers: Endgame, characters do travel through time, but each time they do, it creates a new branch on an existing timeline.

These are the basics. There are variations, like river theory or using flashbacks, but they pretty much all build on these three.

Regardless of which theory you employ, there are a few guidelines you should always keep in mind.

The single most important rule is to Be Consistent. It doesn’t matter what the time travel rules are in your universe, as long as you know them, and you make sure you always, always follow them. Be consistent. Be consistent. Be consistent.

In order to stay consistent, you’re going to need to take notes. Copious, copious notes. If you're traveling to real historical times & places, do your research and get it right. Even if you're in a fictional universe, remember that everything your characters do could be important. Everything they say, anyone they interact with, could cause rippling changes, and the further back the travel, the larger those changes can be. If you're dealing with interactive fiction - like a role-playing game - it's probably a good idea to record your sessions.

Forgive the pun, but you’ll also want to be sure you take your time with your story. Any time a character or characters travel through time (either forward or backward), stop and check your notes. Make sure you've got everything lined up, extrapolate answers to questions, figure out as many ramifications to changes made as possible.

If you're writing a novel, end the chapter or section here.

If you're writing a screenplay for a film, use this as a scene- or act-break.

If it's a TV show, go to commercial.

If it's interactive fiction, end the session there.

Now, I said you have know the rules of time travel, but that doesn’t mean your characters have to. 12 Monkeys executes this brilliantly, with Cole traveling back in time to try and change hi