So what are the mechanics of time travel and the time war? Now that we’ve started getting into the “Magic Kingdom” story in earnest, I want to make sure I’m playing fair with my audience, by presenting the rules I’m following. First, here are some principles of time travel itself.
Dominant Timelines: There is no single past, present, or future, but there is always a dominant timeline where travelers from outside a span of time will always find themselves if they land there. This is the one that has the greatest probability of coming to pass, the greatest internal & external consistency, and so forth - the one that “hangs together” the best.
Generally, the goal of a time warrior is to establish a preferred timeline as dominant.
Merge Conflicts: At any point of divergence in time, if the net differences are small enough, they’ll be absorbed into the larger timeline. If that’s not possible, a new timeline emerges. It’s possible - but never guaranteed - that this new timeline becomes the dominant one.
This means there is no such thing as “time paradox”, except in a statistical sense. You can kill your grandfather, but now you’re an orphan who can’t go home again - you can only drop into a new present where you don’t already exist. You can go back again and again and kill your grandfather in a variety of ways, and the net effect is that the dominant timeline is one where he’s still alive in his time, and you just disappeared one day via your time machine, never to return.
Time Threads: Timelines can retain connections to each other through causal (time travelers went and did a thing) or emotional (Summer is Summer) linkages. These threads can permit navigation through the timelines, but are at the mercy of merge conflicts - by analogy, you can drive on this road, but not through a traffic jam.
A tactic of time warriors is to block the threads used by other travelers. Infinity uses this tactic skillfully, and Ghost Girl (and Magus Everard before her) can circumvent it by using the underworld to travel.
Smearing: Going back repeatedly to try the same events again and again muddles the collective probability of the whole. This lets you play in your own little parallel world if that’s what you want, but it makes it increasingly less likely for this parallel to become dominant.
So that’s the in-universe rules. What about my rules as a writer?
- The adversary (in this case, Doctor Infinity) will only make use of assets and elements firmly established somewhere in the fiction
- The adversary may not cheat the rules of time travel, but may use them more skillfully than the protagonists
- The protagonists’ success must not hinge on some obscure minutae of time travel rules or inexplicable super-science, but on diligent effort
- The circumstances of an alternate timeline may benefit the protagonists, but may never solve the current dramatic challenge for them
- We must be able to see the antagonist’s actions, even if we can’t yet predict their significance