Time Travel is a complicated topic – but if you want to use it in a game, a lot of it’s “laws” are going to be set by the needs of the game, not by mere mathematics, physics, or logic. Still, you need at least some idea of what those rules are or your game will soon make no sense at all – and that’s not much fun, no matter how inherently awkward the topic is.
So how can you run time travel?
To start with we have two “degenerate” cases – where real mathematics and logic takes priority over allowing a freewheeling time travel game.
- First up we have genuinely “realistic” time travel – which, regardless of the mechanism used for the actual travel, adheres to the self-consistency principle. All time travel involves stable casual loops. Anything you do was always a part of the timeline, you can’t actually change anything, and you can’t get off the train tracks – although you can discover alternative explanations for things that you hadn’t known about and solve various mysteries. Hopefully there will be plenty of such side-quests aboard the train available during your ride / tour because you aren’t going anywhere else.
This can be fun if you have cooperative players. The mission to get the secret formula from an agent on the Titanic before it sinks may even offer a few side-quests such as “save the historically unknown group of kids” and so on – but the game master has to be prepared to be pretty heavy handed about keeping history on track. The universe is much bigger than any player-character, and it hits harder. Keep trying to disrupt it, and you WILL be permanently stopped – very likely by being freakishly killed by some unlikely “accident”. And what’s happened stays happened – so the characters won’t be pulling much in the way of temporal shenanigans.*
Now if you don’t have cooperative players, or someone is waxing philosophical about “free will”, you may wind up having to hold a total party kill to get them to give up trying to change the past. Similarly, if you allow multiple visits to the same location in space and time, you may wind up with time-travelers tripping over each other as they accidentally arrange pretty much all of history.
- Secondly, and generally unsuitably for most games, we have simple branching-timeline settings, derived from the many-worlds interpretation of quantum theory and / or the notion that “each incidence of time travel splits off a new timeline”. This makes some logical sense – but it will quickly (and irretrievably) scatter the characters across differing timelines, cheapens everything – “Oh stop crying! It’s not like we can’t pick up another Bob…” – and can leave everyone in the game wondering why anything they do matters. For every world you “fix”, you inevitably leave behind at least one that’s still broken – and since people across the universe are multiplying timelines, there are endless copies of you dealing, or failing to deal, with exactly the same dilemmas. This just isn’t a lot of fun.
Now, to move on to the “unrealistic” options…
- Next up we have “Train Station” time travel – the sort of thing that was used in the early episodes of classic Doctor Who. This style of time travel takes the characters to an exotic locale (that they may or may not know something about) to explore or carry out some mission. If they disrupt the timeline in what OUGHT to be a noticeable fashion there will be a handwavium “explanation” about how they didn’t really or how their “interference” actually led to later events happening exactly as they were “supposed to”. Any time travel that occurs during the actual mission will almost certainly be under the control of a game-master character, who will usually double as the cryptic mentor who provides prophecies, missions, and explanations. In any case, after the “mission”, the characters get back aboard the train, leave most or all of the consequences of their actions behind them, visit another station, and get caught up in some mission there.
If you’re using this version of time travel the characters might as well be traveling to alien worlds by stargate or starship, or be “sliding” between alternate universes, or be visiting universes which are highly similar outside of being a bit older or younger, or be taking an ancient subway system between the long-ruined cities (and the bizarre post-apocalyptic cultures which have arisen around them) remaining after some terrible war, or whatever. The “Time Travel” here is just an excuse to go to weird places, with a modest bonus of being able to use “stop so-and-so from changing the timeline!” as a McGuffin to get the characters involved. Again, games like this can be a lot of fun – but they really might as well not involve time travel at all.
- Finally, of course, we have the big (headache-inducing) one – games with full-blown, player-character-controlled, can-alter-the-past, paradox-causing Time Travel. Whether the characters want to fix something, claim some advantage, block someone else, or prevent something, they just might be able to change the past to do it. To quote Doctor Who…
People assume that time is a strict progression of cause to effect, but actually, from a non-linear, non-subjective viewpoint, it’s more like a big ball of wibbly-wobbly… timey-wimey… stuff.
It’s in these settings that you need to actually worry about the forces underlying causality and time travel. Here…
- You CAN split the timeline, but it mostly only happens when the result would be “interesting”, tends to require major changes or interference at “critical points”, and it doesn’t seem to affect the rest of the cosmos beyond whatever solar system you’re operating in (leaving some VERY interesting questions about whether incoming visitors get a choice of worlds). This really makes no sense at all of course. Logically, if you can change the past at all, it should be frighteningly easy. Delay a man on his way home for a fraction of a second and you’ve just rerolled the dice on his future kids. What are the odds that the same sperm will be the one that makes it this time? And even if you can figure out what ten million things went wrong, how could you fix them?
- Occasionally timelines will merge – either creating closed causal loops or simply leaving small contradictions behind (the tree is definitely gone, but some people say that it blew down in a storm, others say it went down in a weird explosion a week earlier). Really major mergers may leave all kinds of immigrants and artifacts from other timelines laying around with no rational origin in the “final” timeline.
- Some split-off timelines are doomed and just sort of “taper out”… Oddly enough, they don’t really seem to come with aliens or much of the rest of the universe. Sure, there are stars – but unless the source of doom is an alien invasion, the doomed world won’t be seeing much in the way of visitors or assistance.
- When you do manage to change the past, reality often gets back on track; someone steps in to replace Hitler and a very similar version of WWII happens anyway, leading to a pretty much identical outcome. When reality doesn’t get back on track… it turns out to be very hard to make a major change for the better (including repairing a foulup) stick, while changing things for the worse is all too easy. Similarly, you will often get visitors from really unlikely sounding terrible futures who want to change history, but you rarely get anyone from (likely far more populous and capable of time travel) nice futures.
- Characters rarely (if ever for PC’s and important NPC’s) simply vanish when someone disrupts their history. They’ll usually know instantly – but if they don’t have some sort of “resistance to paradox” then it usually “takes a while” for such changes to “propagate” – giving the characters a chance to do something about it.
- Characters traveling through time are strongly attracted to each other and to major events; if you go to see Dinosaurs, odds are that you will arrive just before or after that asteroid impact or some other notable event – and will likely run into some other time travelers.
- Sometimes, for no apparent reason, time in an area will just keep looping until events there turn out “right” – however little sense that makes. Quite often, this seems to have something to do with love, which seems to be able to transcend space and time.
- Your actual location in space has very little bearing on where you appear in the past or future after you move through time, but you can be sure that it will be an interesting place.
- Something sometimes, but not always, enforces temporal equivalence, wherein if you spend a day in the past, one day passes in the present.
- You can have “Time Storms”, “Fixed Points In Time” (events that cannot be undone), “Temporal Rifts / Gates” (holes through time that lock differing times together), “Anti-Paradox” or “Temporal Fixator” fields (that keep things from vanishing when their history is changed), Temporal Exclusion Principles (preventing repeated meddling, or too much meddling, or keeping people from meeting themselves – or providing quarrelsome evil temporal dopplegangers), “Temporal Rejection” (the timeline itself throws out people who annoy it), “Temporal Absorption” (people are gradually “fitted into” the current timeline and into their location in time, pick up and losing memories as they do so), “Time Reversals” (with very selective effects as to who and what is affected and to what extent), Age-Shifting (for no real reason), “Temporal Exemptions” for things and areas that exist “outside of time”, “Temporal Cloning” (wherein famous and recognizable individuals continue to be pretty much the same people in the same roles despite history being unrecognizable), and “Temporal Constants” (wherein particular people, items, relationships, or events show up even if they don’t really fit into a new timeline).
- Sometimes you can’t take anything with you and sometimes you get mutually exclusive sets of grandchildren showing up to visit – and to lobby for which set of them will actually get to exist.
Yes, you can have ALL of this under a single set of rules that actually makes at least some sense – thanks to a version of the Strong Anthropic Principle.
Within the lower worlds, the realms of matter and energy and time, souls may dance through a myriad times and sequences, living through experiences both wonderful and terrible as chance and their own whims direct. But their true existence lies elsewhere, within the higher realms – which may have their own principles of Will, Change, Sequence, and Separation, but which are not bound by Life, Death, Space, and Time.
Every soul has a certain amount of control over Life, Death, Space, and Time even within the constraints of embodiment in a lower universe. On the personal level, souls may cling to life, hang about as ghosts after death, arrive in the nick of time far more often than is rationally likely, experience moments of deja vu, distort time in emergencies, experience precognitive flashes, see into the past, and more – drawing upon their true existence within the Forge of Souls.
Love can indeed transcend time, for a true bond between souls is a thing of the higher realms.
Despite this underlying democracy, some souls can do more than others, at least in some times and places. Such souls are resistant to death and paradox, find their lives filled with strange and exotic coincidences, experience many interesting things – and so fill the ranks of heroes and great villains, time travelers, and other adventurers.
Still, everyone gets at least one vote – and people do NOT like being erased from existence, and they don’t really like being split between timelines too much either. Neither do they like having to revise their pasts. Thus…
- The timeline resists splitting unless the resulting secondary timeline will be different and interesting enough to bring in enough local “Votes” to sustain its existence – at least for a while – despite the inconvenience. This is usually only local (a single planet at most), leans towards “critical point” splits because people find them easier to keep straight, and runs towards exciting disaster realms because killing off most of the population that doesn’t want to be bothered reduces the “no” votes resulting from people having to split their existence and provides excitement for the ones who do try it out. Timelines can merge because the past does not HAVE to be consistent if the people involved don’t want it to be; people tend to remember things differently from each other anyway. Visitors can come from (or flee) doomed timeline offshoots easily enough though – no matter how unlikely their offshoot timeline is.
- It’s hard to change the past in the face of all the people who are used to it the way it is – but it does get done at times and the changes that the majority tend to keep are usually the ones that either improve things or make them more dramatic and exciting. Thus the “true” timeline holds many incredible coincidences – and if you DO manage to push a large change through, it is almost always for the worst because the timeline is already at least somewhat optimized. Similarly, it’s hard to really improve the world with time travel; most of the “easy” fixes are already in place.
- Important people tend to already be on the high-end of time control abilities – and so will often manage to keep many of the details of their personal stories intact even if you do manage to change their pasts. Similarly, changes ripple up the timeline as consensus on them grows – creating perceived time between changes in the past and them taking effect in the future.
- Major events get a lot of attention, and thus are more “real” and “fixed” than less distinctive moments – and so tend to draw in time travelers, Time travelers are drawn to each other thanks to their shared intent.
- “Groundhog Day” temporal loops are basically a symptom of a local group of souls who cannot quite agree on how they want things to go – and so keep revising a segment of time until they find it satisfactory. Similarly, major authorial arguments can result in time storms, very popular scenes act as “fixed points in time”, “edit wars” manifest as time storms, powerful individuals can protect themselves from paradox through machines, talismans, spells, or simple willpower, overly troublesome characters may be “written out” (and may wander off to join other Wikis, or raid this one), and so on. The universe really DOES tend to follow literary conventions because – at it’s most fundamental level – it’s a multi-author novel being “written” and “revised” by the largest possible committee.
This explanation will not make the physicists (if any) in your group happy – but it will let you have some notion of how your Timey-Wimey universe functions. It’s a Wiki. Most souls settle for reading it and never log on to change anything, others tweak details they find personally important, and a few will really dedicate themselves to improving the thing. Some will have special privileges as editors or administrators, some will insert entire pages that don’t seem to relate to much, or throw in alternate “what if” versions of things, and a few will involve themselves in edit wars or wind up being banned.
And enough small edits… will generally result in some decent articles / segments of history.
Eventually – at least in terms of the higher realms of the Forge of Souls – the narrative, it’s side-passages, and everything about it – will approach a final form as souls lose interest and wander off to other projects, leaving the final meddling to a few diehard souls who will acquire the various administrative positions by default (and sometimes these elder ones will start to harass other projects…).
*I must admit that causal loops can be a lot of fun for the game master. I have greatly enjoyed maneuvering the players in appropriate settings into looping their characters without noticing it. The moment when they realize that they just set up their own prior adventures, or arranged for each others pasts, or rescued and planted the ancestors of the group that was so inexplicably helpful later on, is always a lot of fun.
Of course for that to work properly you’ve got to have a very large, long-term, campaign (otherwise the players tend to catch on too fast), work on subtly steering the players (so that their actions will be at least vaguely compatible with later history), make a habit of tying loose facts back into the game (thus making it look like you brilliantly had it all plotted out in advance), and be good at narrating exactly why whatever results you get “inevitably” led to the history the players are used to (fortunately the players will usually start helping out with this once they catch on).
Thus for example, I once threw in a throwaway fact; a newly-encountered species of helpful insect-folk in a quasi-oriental realm sold the characters supplies to help out on a great quest – but let one character have a bunch of stuff free due to some “ancient debt”.
As it happened, that character was a semi-immortal professional familiar, who drew a lot of his power and skills from a symbiotic relationship with another character – but when something happened to that character, said familiar simply picked another companion, dropped the abilities associated with the prior companion and added some new ones.
Some time later the players opted to take a break from the main campaign. They’d been looking at the campaign history and wanted to play a few adventures set shortly after the great cataclysm thousands of years before – exploring the wilderness and building new civilizations rather than negotiating a world full of ancient ones.
Most of them made new characters of course, but Richard was quite content with the semi-regular rewrites of his professional familiar – and his character had the lifespan, so he simply played a younger version. with a note that – if he got killed – presumably someone would bring him back over the next few thousand years.
In the course of exploring a network of interstellar gates, the group stumbled across, and rescued from a most unsuitable planet, some stranded swarms of intelligent insects who could re-design their forms to meet their current challenges. After some consideration of their racial nature, they decided to plant them on the continent with proto-oriental cultures that seemed compatible.
I had quite a laugh before they caught on and started counting up the number of ways they’d looped themselves or arranged for their own adventures later.
In the Champions game, the Lords of Time are senior site administrators who got in on that aspect of things near the beginning – and anyone who finds themselves ABLE to engage in major time manipulations has been granted some authority to edit sections of the cosmos. Of course, given that they’re operating mostly outside of time, and are very very old and powerful indeed… the motives of the Lords of Time can be pretty weird. The Lords of Time enforce the self-consistency limitation on the Celestial Dragons simply because they’re one of the few universe-spanning races and many of their past regrets have had very deep effects indeed. Allowing them to rewrite THOSE… would change far, FAR, more than anyone is really comfortable with.