• Welcome to the Fantasy Writing Forums. Register Now to join us!

Is it possible to write about Time Travel without making paradoxes?

Ruby

Auror
I'm writing a Fantasy in which several of my main characters are time travellers. It's turning out to be a lot more complicated than I'd expected.

I thought I could simplify things and make a rule that when characters time travel, they disappear. They reappear only when and if they return ( as opposed to dividing into two people, one who time travels, the other who stays and continues their normal existence).

I thought I had it sorted but now I think there would still be a paradox, because if they return to the moment they left, then they won't have disappeared and so the plot regarding what happened when they disappeared will no longer exist, as they didn't disappear. Although they did, but only they know about it. :confused:

So, is it possible to write about Time Travel without making paradoxes? :D
 
I actually once wrote a story about two time thieves who went back in time in order to defeat an evil empress. I had the benefit of it being a prequel to a story I had already written, however. So I used events from the other story to essentially crease out any paradoxes.
However, it would be very difficult to create a paradox-free concept of time travel. You would either have to create divergent timelines, somehow write their actions into the history of the world seamlessly, or simply have them reappear a second after they disappeared, but in that one second, a hundred life times passed for them.

Or if you're up to the challenge, you could manipulate the paradoxes to your advantage. Reflect the changes that they made on the world in the future, or even have the changes that they make already present before they even disappear. Time travel is very frustrating to write, in my experiences, but I'm sure you can find a solution.
 

Queshire

Auror
I have two opinions on how to handle time travel.

First off is why the hell would the universe care about paradoxes? That they can occur is proof that they're possible, just because our puny human mind isn't wired to be able to understand it doesn't mean much. Humans are limited after all.

Second off is that time travel is just jumping from one alternative universe to another one which happens to be exactly the same as our own only a little bit ahead. Think of it as having two copies of a movie playing only one movie is at a later scene than the other. Time travel would be just jumping from one screen to another. Ok, so that wouldn't technically be time travel but it would have all the benefits of time travel without any of the paradoxes! You wouldn't really be killing your own grandfather, you'd just be killing an alt you's grandfather and it wouldn't be you that hops back to die in your arm, but an alt you. (Though since the only difference is what scene in the movie you're world is on, it's probably a good idea to heed the alt you's warning.)

I suppose these don't help in your case though. Hmm.... Well, you could have the reality where they didn't disappear replace the one where they did, retconning any differences due to that, but that makes the events in the reality where they disappear pointless. The other option is that they pop up back in where they originated from an equal temporal distance to how long they spent outside of their native time frame. So if you decide to go vacationing with the dinosaurs for a year, when you return to the present a year would have past.
 

Penpilot

Staff
Article Team
I guess it depends on how you define the "rules". Is there only one timeline or are there divergent ones, where every possibility of existence is played out? How do you handle the butterfly effect? If the butterfly effect is in full play, then travelling back in time can have massive unforeseen consequences. Something as simple as bumping into someone can conceivably prevent time travel from being invented. Or is the butterfly effect not in play because the universe won't let it happen?

Trying to make time travel work flawlessly can become a headache, but it starts by figuring out what rules you want to impose.
 

Julian S Bartz

Minstrel
My brain hurts thinking of time travel.

I think it is impossible, however you need to decide what you are going to explain and what you are going to leave unsaid. Most time travel stories have plot holes, but people who like them are willing to accept certain things being left out. For the very reason that you can't cover off every aspect.
 

Wormtongue

Minstrel
Time travel forward does not risk paradoxes.

Time travel backward would inevitably lead to paradoxes, except... As it was explained to me by a physicist, anything you do in the past to try to change events would only result in the events happening exactly as they did.

I wanted to write a story about time travelers who went back in time to stop Hitler, but in the end only wound up causing him to come to power. I gave up that idea when I realized how much research would be involved to get the historical events right.
 

Ruby

Auror
I actually once wrote a story about two time thieves who went back in time in order to defeat an evil empress. I had the benefit of it being a prequel to a story I had already written, however. So I used events from the other story to essentially crease out any paradoxes.
However, it would be very difficult to create a paradox-free concept of time travel. You would either have to create divergent timelines, somehow write their actions into the history of the world seamlessly, or simply have them reappear a second after they disappeared, but in that one second, a hundred life times passed for them.

Or if you're up to the challenge, you could manipulate the paradoxes to your advantage. Reflect the changes that they made on the world in the future, or even have the changes that they make already present before they even disappear. Time travel is very frustrating to write, in my experiences, but I'm sure you can find a solution.
Hi McBeardstache the Hairy, I'm also writing the Time Travel story as a prequel to my WIP(unfinished). I decided that an Ancient Supporting character was actually a time traveller, forced to move forward in time against her will. I started writing her story as a prequel for NaNoWriMo. So I now have ancestors of characters in one book and their descendants in the other, with obvious overlap for the time travellers.
In the plot of your story, wouldn't there be a paradox if they went back to defeat the evil Empress, therefore nullifying the events of the other book?
 

Ruby

Auror
I have two opinions on how to handle time travel.

First off is why the hell would the universe care about paradoxes? That they can occur is proof that they're possible, just because our puny human mind isn't wired to be able to understand it doesn't mean much. Humans are limited after all.

Second off is that time travel is just jumping from one alternative universe to another one which happens to be exactly the same as our own only a little bit ahead. Think of it as having two copies of a movie playing only one movie is at a later scene than the other. Time travel would be just jumping from one screen to another. Ok, so that wouldn't technically be time travel but it would have all the benefits of time travel without any of the paradoxes! You wouldn't really be killing your own grandfather, you'd just be killing an alt you's grandfather and it wouldn't be you that hops back to die in your arm, but an alt you. (Though since the only difference is what scene in the movie you're world is on, it's probably a good idea to heed the alt you's warning.)

I suppose these don't help in your case though. Hmm.... Well, you could have the reality where they didn't disappear replace the one where they did, retconning any differences due to that, but that makes the events in the reality where they disappear pointless. The other option is that they pop up back in where they originated from an equal temporal distance to how long they spent outside of their native time frame. So if you decide to go vacationing with the dinosaurs for a year, when you return to the present a year would have past.

Hi Queshire, yes I also thought why would anyone care about paradoxes? In fact, I just had a brainstorm one day and decided, "I know, she's not just ancient she's a time traveller!" without even realising that paradoxes exist. However, I soon learnt about them and became confused. :confused:

Re the grandfather problem you mention, I thought I'd solved that by allowing another time traveller to be friends with his grandfather who also time travels. But at the beginning of the prequel he comes to fetch the MC to the future but, unfortunately, arrives in the wrong year, thus making a paradox: they meet before they've met etc :eek:

I like your suggestion that they could not return to the original time they left and a year away would still be a year in real time. But would that really work as a plot device?
 

Ruby

Auror
I guess it depends on how you define the "rules". Is there only one timeline or are there divergent ones, where every possibility of existence is played out? How do you handle the butterfly effect? If the butterfly effect is in full play, then travelling back in time can have massive unforeseen consequences. Something as simple as bumping into someone can conceivably prevent time travel from being invented. Or is the butterfly effect not in play because the universe won't let it happen?

Trying to make time travel work flawlessly can become a headache, but it starts by figuring out what rules you want to impose.

Hi Penpilot, what is the "butterfly effect"?

I agree that I'll have to make my own rules. This is giving me a headache, also known as "writer's block"!:D
 

Ruby

Auror
My brain hurts thinking of time travel.

I think it is impossible, however you need to decide what you are going to explain and what you are going to leave unsaid. Most time travel stories have plot holes, but people who like them are willing to accept certain things being left out. For the very reason that you can't cover off every aspect.

Hi Julian S Bartz,

I think you are right.

I recently watched a video on You Tube where someone talked about all the plot holes in the film, Back to the Future. Maybe, the readers/viewers just have to suspend an awful lot of disbelief for this genre.
 

Ruby

Auror
Time travel forward does not risk paradoxes.

Time travel backward would inevitably lead to paradoxes, except... As it was explained to me by a physicist, anything you do in the past to try to change events would only result in the events happening exactly as they did.

I wanted to write a story about time travelers who went back in time to stop Hitler, but in the end only wound up causing him to come to power. I gave up that idea when I realized how much research would be involved to get the historical events right.
Hi Wormtongue,

A physicist told me that, strictly speaking, you can only time travel forward in time.

However, recently I was on a plane and discussing time travel paradoxes with a companion. We concluded that time travel is just fantasy. Then we landed and had to put the time on our watches back two hours! :D
 

Queshire

Auror
Time travel forward does not risk paradoxes.

Time travel backward would inevitably lead to paradoxes, except... As it was explained to me by a physicist, anything you do in the past to try to change events would only result in the events happening exactly as they did.

I wanted to write a story about time travelers who went back in time to stop Hitler, but in the end only wound up causing him to come to power. I gave up that idea when I realized how much research would be involved to get the historical events right.

That's one of the ways time travel is commonly portrayed in fiction. Since time travel doesn't exist in reality it can't be said to be how it would work in reality with any certainty, but, sadly, I wouldn't be surprised at all if it was how it worked. As a wannabe writer though, I don't like that answer. It makes any action by the time traveler pointless as they were always fated to do what they did. There's no real agency there, no free will, just dancing at the strings fate has you on.

@Ruby: In essence the butterfly effect says that small changes in the past can have a huge effect on the present / future, for example saying that stepping on a butterfly in the past can result in the Nazi's having won WWII. Or for another example say you travel back to ye olde times and you get attacked by a desperate no name bandit on some muddy road in the ass end of nowhere. You take your fancy lazer blaster and shoot him dead. SURPRISE! That guy was the great great great great great (etc and so on) grandpa of Abraham Lincoln and suddenly the entire course of American History is changed due to that one act.

Personally I think most people that use the Butterfly Effect in stories have these huge dramatic changes to the course of history as a result of the smallest most insignificant change. I'm not a fan of using it in that way. It's an extreme example of the effect and overdone. It would be more interesting to a more subtle butterfly effect that isn't obvious at a glance. For example having the actions of a time traveler result in America named after Christopher Columbus instead of Amerigo Vespucci.
 

Devor

Fiery Keeper of the Hat
Moderator
It's possible to have some time travel without paradoxes, and to have some paradoxes without driving readers crazy. But there's a fine line there somewhere, especially when it affects the coherency of your plot.

Most of the more successful time travel stories I can think of use a light and humorous tone to lower the threshold for suspending disbelief. The more serious stories keep the time travel to a minimum to avoid making it a problem. Even Doctor Who keeps the time travel to a minimum within a given episode.

You can lampshade it, but the thing to avoid is calling attention to the paradoxes or relying on them for plot purposes. Just keep it simple. You want the readers to think they understand how it makes sense for you.
 

Wormtongue

Minstrel
Time travel has not been proven to be physically impossible. But our current understanding strongly suggests that it is practically impossible. And by that I mean impossible in practical terms, at least on any scale larger than atoms.

The physicist I mentioned earlier explained it to me like this. The only balanced solution to a time travel equation requires nothing in the past be changed. On a quantum level this is easier since nothing is precisely defined so any attempt to change, for instance, the path of a particle could be absorbed by the quantum uncertainty. The particle could continue on it's merry way as it originally had, resulting in a balanced equation.

This effect wouldn't solve the problem on a macro scale.
 

Gryphos

Auror
This may be a bit off-topic, but I once came to the conclusion that time doesn't exist at all. We only invented the concept of time to put things in order, looking at the past and to the future. But technically neither the past nor future actually exist. All that exists is the present, this exact moment. All the time the present is becoming the past and in doing so ceases to exist. The past existed for that exact moment that it was the present, and the future of course doesn't exist because it hasn't happened yet, but it will when it's the present. Because of this, I'm convinced that in the real world time travel will never be possible.

Of course in a fantasy story that doesn't matter and you can make time travel possible with matter.
 

Steerpike

Felis amatus
Moderator
The universe moves causally from one point to the other, and changes states at is goes from one to another. That was the case long before humans were around to invent a concept of time. We may have invented time as a "concept" but we use it to label a real property of the universe.

As for time travel, I don't think physics has rendered travel backwards in time completely impossible (there was an interesting SciAm article on this a number of years ago). Travel forward is certainly possible. The easiest way to resolve paradoxes from traveling backwards is to have the timeline split at the point of any possible paradoxes, so that two separate universes exist (the original and the altered one).

By the way - just going back in time to the same universe you left from is altering the past, and also appears to me to violate some laws of physics, so unless you do something like split the timeline, you've got a big problem.

I read a theory once in a science journal that every time the universe is confronted with a choice (they were talking at a quantum level I think) there is a splitting of the timeline into two separate universes - one in which each choice is made. According to this theory, the timelines merge almost immediately if the choice is minor, take long to do so for more major changes, and if the change is significant enough they never merge. You could work with something like that.

But it seems to me that if you really want to make sure you don't run afoul of paradoxes at the instant the person travels back in time, you completely sever the timelines into two universes.

Even then you've got the problem of adding matter to the universe (remember that the laws of physics, and conservation of mass and energy). I suppose it is open to debate whether or not the universe remains a "closed" system if time travel is feasible. If not, then perhaps those laws don't apply.
 

Penpilot

Staff
Article Team
Hi Penpilot, what is the "butterfly effect"?

The butterfly effect is that small changes can have large and unforeseen consequences. For example, your MC time travels backwards. A few moments after they arrive, they bump shoulders with some stranger. That bump can cause an ripple effect like a pebble dropped in a pond that touches everything around them. Now that bump causes the stranger to pause for a second to look at your MC. It seems like a nothing interaction, but here are a few things that can happen.

- Because the stranger pauses to look at your MC, they miss meeting eyes with their future wife, and that stops them from ever marrying and having a kid. That kid will never invent the cure for cancer.

-Because the stranger pauses, that makes the person behind them pause too. So everyone behind is a step behind their normal pace. This causes one of them to be one second behind in crossing the street as a runaway dump truck comes roaring by. Before the dump truck missed the person by a second, now the truck hits that person. When this happens, it doesn't just kill that person. It will kill every descendant that person will have, and will affect everyone that person and their descendants will ever interact with in the future. It in effect causes a shockwave through time with unpredictable consequences.

As each of us moves through time and space we affect all those around us in tiny ways, but each of those interactions is part of a cause and effect equation. Add or subtract something from that equation, it won't add up to the same thing.

Remember that pebble in the pond analogy I made above? Now imaging a pond with billions of pebbles being dropped into it. Imagine how the ripples interact, cancelling each other out or reinforcing one another, creating a pattern of ripples. Now try and predict the pattern of change if you stop a single pebble from falling in or drop a new pebble in? It's near impossible to tell what the new pattern will be. All you know is ripples go out, or don't, and how they interact and the end result will be different.

The name Butterfly Effect comes from a short story by Asimov or Bradbury, I think, named The Sound of Thunder. In it somebody travels back in time and accidentally steps on the butterfly and significantly changes the future.
 
Last edited:

Ruby

Auror
It's possible to have some time travel without paradoxes, and to have some paradoxes without driving readers crazy. But there's a fine line there somewhere, especially when it affects the coherency of your plot.

Most of the more successful time travel stories I can think of use a light and humorous tone to lower the threshold for suspending disbelief. The more serious stories keep the time travel to a minimum to avoid making it a problem. Even Doctor Who keeps the time travel to a minimum within a given episode.

You can lampshade it, but the thing to avoid is calling attention to the paradoxes or relying on them for plot purposes. Just keep it simple. You want the readers to think they understand how it makes sense for you.

Hi Devor, I find your advice very helpful.

I especially like the Doctor Who reference: yes, the characters don't have to time travel constantly. In fact my MC gets stuck in the future for many years.

Thank you! :)
 
Top