Travelling the space-time continuum

[Dreaddisease]

I spelled continuum right. Thats great.

I have a question. I'm adding some elements of time travel to the campaign (not the PCs, just some strange NPCs) and I'm wondering how other people have approached this issue. We have all seen the Star Trek episodes and movies like Terminator and the Time machine and I was wondering what elements you used, how you use them and how do avoid the obvious logical errors of time travel? BTW, if you use(d) predestination and the fates then that is another story and I would like those discussions but I probably won't be using those as I can find very bad logical errors when it comes to time travel.

To begin, obviously the realm of time travel encounters many problems. If a person is able to move into the past in one way or another his actions will alter the future. If there is the belief that the past is fixed than the presence and influence of someone going into the past will not be felt (much like someone watching a movie). This would be useful for men of knowledge such as loremasters but practically useless as a utility, and in the D&D realm a loremaster would be better off using spells (like Legend Lore) to learn these things. To retrieve items, influence decisions or prevent occurances from happening someone would need to interact with his surrounding environment. A Time Traveler in this state would thus be either a result of his interaction with the past (i.e. Terminator), a victim of the fates (I.e. Final Destination, The Time Machine) or influencing a past not his/her own (Parallel universe).

Brain hurt. Please give contributions....

 

[Dreaddisease]

Brain still thinking, must type.

Using the magics...
Obviously a time travel 'spell' would be very powerful. Balancing this spell would be necessary. If the effects of the spell cannot influence your present state then the spell would be a improved scry, being able to find the reasoning behind something and then being able to react to it in the present. This ability would still be greater than any spell on any list now, Combining Foresight with scry.

 

[LostSoul]

I think you should try to do it like they did in Terminator and Babylon 5. When you go into the past, you make the future the way it is. This might be a problem because it seems like everything is predestined, and the PCs don't really have a chance to affect things - but your timeline already assumes that the PCs have gone back in time and have done what they did to make the timeline the way it is. Adventures in the past can be just like any normal adventure, you just need to come up with some creative thinking so that whatever the PCs do, their actions create the future.

 

[Umbran]

This might be a problem because it seems like everything is predestined, and the PCs don't really have a chance to affect things - but your timeline already assumes that the PCs have gone back in time and have done what they did to make the timeline the way it is.

So, it is not a problem logically. It's still a problem dramatically.

Think - your timeline already assumes that the PCs have donewhatever it is they will do. The timeline is fixed. Would you like to bother playing through a thing, knowing that your choices as a player mean nothing, as the conclusion is already known? Stop the bad guy or not, the future is already known? Why bother risking your neck? This structutre removes a great deal of player motivation, and makes them feel less like participants, and more like observers.

Two possible rescues from that predicament -

1) Don't let the players know that the future is a forgone conclusion. They'll still be cheesed if they ever find out it was fixed, but lyou don't ever have to tell them that you set up a scenario where their actions were essentially meaningless.

2) Don't make the future fully fixed. Specifically, design the scenario so that the results of their past actions will only be noticed after they return. Like so: Go back 1000 years, face the Big Bad. If you kill him, he's dead for all eternity. If you don't kill him, the Big Bad still winds up trapped for 1000 years - to be released soon after the PCs return to their normal time.

 

[the Jester]

I've used time travel stories in the past.

If the pcs change the 'present' then they're the only ones who can remember how it used to be. There may be dramatic differences in the world or virtually no differences, but nobody but the pcs will know the difference.

I think of time as like a river. It tries to flow in the channel that it's carved and will try to correct as much as possible any deviations that time travelers cause. The farther back the pcs go, the easier it is for time to correct their revisions. So if they kill the big evil arch-devil a thousand years before they first met him when he came to conquer their lands, maybe he's been impersonated and replaced by his son or former right hand man or what have you in the present. If they bring down the vast empire that they oppose a hundred years before game present maybe it's been replaced by a new one. Etc.

 

[der_kluge]

Once upon a time (pun intended), I had created a 2E Planescape PBEM game in which one of the core characters was a Chronomancer, and there was another that was a Priest of a Time God.

I made up all the characters, and then stripped them of their memories. They were about 15th level, I think.

The story went like this :
The Time God spoke unto his priest (one of the PCs), and told him that he and his friends (along with the Chronomancer) needed to travel back to time into Mechanus to stop a wizard from creating a powerful artifact. This artifact would eventually cause some major rift in the Blood War, and alter the balance of power. The details of this were never fully fleshed out.

So, the party goes back in time, lands in Mechanus, just as the artifact is being created - their timing was off. They land in the wizard's lab, and this creates a rift in time. As a result, their minds all got stuck in minor magic items in the wizards lab, and their bodies got sucked back into the Astral plane. One of the PCs had a Githyanki sword (the party was of sufficient level to take care of any Githyankis that kept trying to take it from them).... well, now they were abandoned to the Astral - bodies floating, memories gone. And, since this was about 50 years in the past, in modern times, their memories have traveled in magic items from owner to owner to owner for 50 years.

This was all -backstory-. The game started as the PCs awoke aboard a Githyanki Astral ship, in a holding cell, until an Astral Dreadnaught appears, and crushes the ship in half, allowing the PCs to free themselves, and hop into a nearby portal which leads to a pitch dark cavern in Pandemonium.....

The idea was for the PCs to follow clues amongst their gear to track down each of their memories, so that they could regain their powers.

The PBEM died out fairly quickly, though, and we didn't make it very far.

 

[Jürgen Hubert]

Buy GURPS Time Travel. It explains everything you need to know about paradoxes and other problems in a format easily digestible for gamers.

Don't be put of by the GURPS part of the title. The rules parts are minimal, and easily discarded.

 

[Guilt Puppy]

Just imagine if villains had time travel...

BBEG: Mwuahahah! Foolish mortals, you think that you can defeat me? Mwuahahah! But before I annihilate you, might I have the pleasure of knowing who it is that has disturbed my peace?

PC: I am Voorhas of Elembar! And I have come to end you evil sche--

(BBEG poofs out, then poofs back. Suddenly, Voorhas was never born.)

Player: %!@#

 

[bondetamp]

The way I deal with time travel paradoxes in rpgs is to flatly disallow any time traveling to the past.

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.

 

[s/LaSH]

Several main ways of dealing with time travel.

One: Divergence. Once you interfere with the past, you change the future. (Whether the timestream corrects itself, or veers off wildly, is a sub-variant.) eg. You kill your grandfather and when you return to the present, nobody knows you exist. This is the one I like (Trousers of Time).

Two: Solid-state. You have already interfered with the past, which is normally why you get to interfere with the past in the first place. eg. You go back in time and accidentally mention to someone that you are from the future, so they try to build a time machine which you end up using.

Three: Compromise. Spacetime is organic, and when you alter it it has to heal itself. Your actions don't always have the logical result. Tiny quantum actions can cause massive ripples in reality. eg. You go back in time and shoot John Wilkes Booth before he can go to the theatre. The Universe doesn't like this, and history scabs over so that someone else with a grudge goes to the theater that night; Lincoln's still dead by assassination.

Four: Total weird-out. This is difficult to describe, but you can throw nearly anything together in this way. My personal favourite is a solid-state that springs Athena-like from the ether, simply because of something that happened within it - before it existed. You may commence the brain-bleeding now.