Travelling the space-time continuum

[Bagpuss]

The trousers of time is one of the more interesting ways to go with only the time travellers having any recollection of whats down the other leg.

IE: You go back in time and accidentally run over your own grandfather.

Instantly your, facial features change slightly, you drivers licence changes from reading Tony Smith to Anthony Smythe. You retain all the recollections of your past life, but when they return to the future they discover weird things, like they arn't married, live in a different apartment, some of the people they recognise don't recognise them, other who they think they have never seen before treat them as old friends.

Changes can be as big or small as you like, usually the bigger the event they alter the bigger the changes you create when they get back to the future. You should have mapped out some ideas for how events might change depending on their actions.

 

[Dreaddisease]

Reply to bondetamp.

Disallowing travel to the past won't necessarily solve the problems. The present is the future's past. Travelling to the future can alter it. Simply by stating that the future is not a set state can be a solution but how can the future be determined if a person travels there to learn what action to take.

Let me rephrase and clarify. Person BJ (PBJ) is at a crossroads. Instead of trying to use the past and present to determine which path to take he travels into the future to see what happens and what path he took. The paradox reoccurs in the future tense because he hasn't made the decision. There would be two futures (or more) because the decision is not yet made, so which one does PBJ encounter?

Going into the past is much the same paradox. Of course I do like the parallel universe solution. Travelling into the past either creates a parallel universe or you encounter the parallel universe instead of your own. This would preserve your past. Unfortunately if you do not return to the right universe you are permentantly stuck in a different world (Sliders).

In another option the use of fates, inevitables, destiny and predestination is a way of solving the problems. Though I do not like the logical problems and the feeling of not being in control for the people the benefits are numerous. Divine servants of Time prevent you from killing your grandfather because that would mess up the order of things and it wasn't determined beforehand.

 

[Napftor]

Once upon a time last year, I was in talks with Natural 20 to pen a time travel supplement. Regrettably, other projects consumed my time (and still do), so the matter was left in limbo (if you're reading this Morrus/RangerWickett--sorry guys!). I still have all of the notes and one day hope to do something with them. I can tell you that the river concept is something I was using and that at the "present" there were an infinite number of tributaries reaching into the future (or downstream). These, of course, represent the choices that any person or creature might make that throws the present stream onto a certain route. So, going into the future is certainly possible, but chances are better than good that it won't be the one that actually happens.

Time travel changes are also dependent on how far you're travelling from the present. A couple of days into the past? Probably not much will happen unless you're performing a major undertaking. I developed a chart that cross-references distance into the past with the kind of activity and exposure the PCs are undertaking. The outcome of these two things determines what sort of disruption in the timestream you're in for when the PCs return to their present.

I can't remember what I did about the grandfather paradox, but I do know that I resolved going back (or forward) and meeting yourself--you can't. Keeping with the stream analogy, the PC is a rock in the stream. When you travel into the past (or future), the rock is moved down or up stream. There is, and can only be, one rock. Simple, but it works. The PC that was in the time the present one is shifting to is replaced. This is why travelling to a point in time in which your character lived is so problematic. If the PC is at his house on a certain date and time, and you're popping in at that time at a faraway location, then chances are you're going to have a serious disruption on your hands when you return. Especially if your past self was doing something important on that date.

Well, I don't want to give everything away in case I do manage to put together a supplement, but there's my core thoughts on the matter.

 

[Kage Tenjin]

If I did, though, Terry Pratchet did (as far as I know) coin the phrase "Trousers of Time". Basically, whenever you go to the past and change anything, you create a different reality continuing based on what you did, while the main timeline continues unchanged. Back to the Future used this way of looking at it, and it works quite well.

Check out Night Watch, his latest book. He uses the self-correcting time travel theory as well. Whatever happened, will stay happened, although minor details might change.