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



## Ruby (Mar 12, 2014)

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. 

So, is it possible to write about Time Travel without making paradoxes?


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## McBeardstache the Hairy (Mar 12, 2014)

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.


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## Queshire (Mar 12, 2014)

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.


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## Penpilot (Mar 12, 2014)

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.


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## Julian S Bartz (Mar 12, 2014)

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.


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## Wormtongue (Mar 13, 2014)

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.


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## Ruby (Mar 13, 2014)

McBeardstache the Hairy said:


> 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?


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## Ruby (Mar 13, 2014)

Queshire said:


> 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.
> 
> ...



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. 

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 

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?


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## Ruby (Mar 13, 2014)

Penpilot said:


> 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"!


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## Ruby (Mar 13, 2014)

Julian S Bartz said:


> 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.


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## Ruby (Mar 13, 2014)

Wormtongue said:


> 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!


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## Queshire (Mar 13, 2014)

Wormtongue said:


> 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.


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## Devor (Mar 13, 2014)

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.


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## Wormtongue (Mar 13, 2014)

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.


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## Gryphos (Mar 13, 2014)

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.


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## Wormtongue (Mar 13, 2014)

That thought is similar to something I came up with years ago.  "The past never was, and the future never will be."


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## Steerpike (Mar 13, 2014)

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.


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## Penpilot (Mar 13, 2014)

Ruby said:


> 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.


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## Ruby (Mar 14, 2014)

Devor said:


> 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!


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## Ruby (Mar 14, 2014)

Wormtongue said:


> That thought is similar to something I came up with years ago.  "The past never was, and the future never will be."



Yes, all we have is the moment we live in, like NOW.


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## Ruby (Mar 14, 2014)

Steerpike said:


> 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).
> 
> ...



Hi Steerpike,

Thanks for explaining this. 

But, of course, this just shows how complicated it is. If I split the timeline, I will have multiple versions of the same characters wandering around in space and time, won't I? How on earth would I structure such a book? I already have at least four different time travellers in the plot!


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## Ruby (Mar 14, 2014)

Gryphos said:


> 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.


Hi Gryphos,

So you're saying that although time doesn't exist, it should be possible to time travel?


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## Ruby (Mar 14, 2014)

Penpilot said:


> 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.
> 
> ...



Hi Penpilot, thank you for taking the time to explain all this. 

I didn't know it was called 'The Butterfly Effect' but I'd already encountered this problem in chapter two of my WIP when the time traveller, who's a master wizard, has arrived in the wrong year to bring the MC back to the future. His time machine has malfunctioned and he's two years earlier than planned so, although he's met her, she hasn't met him. Now they're going to time travel forward two years but that's going to cause a paradox, isn't it?

I'm probably going to have to rewrite this whole plot or let him use magic instead. Maybe, he'll have to disappear by himself and meet her in the correct year, but even then there would be a paradox!


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## Steerpike (Mar 14, 2014)

Ruby said:


> Hi Steerpike,
> 
> Thanks for explaining this.
> 
> But, of course, this just shows how complicated it is. If I split the timeline, I will have multiple versions of the same characters wandering around in space and time, won't I? How on earth would I structure such a book? I already have at least four different time travellers in the plot!



No, there wouldn't be any communication between the timelines, and travel between them wouldn't be possible. I've seen stories that use alternate timelines to get rid of paradoxes, but I don't think I've seen on that addresses the conservation of mass issue, though I can think of how you might do it. But most time travel stories hand wave these issues.


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## Gryphos (Mar 14, 2014)

Ruby said:


> Hi Gryphos,
> 
> So you're saying that although time doesn't exist, it should be possible to time travel?



No, I said that it wouldn't be possible in the real world, but in a fantasy story you could have it and just put it down to magic.


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## The Dark One (Mar 14, 2014)

I think most of this is way too complicated for a story. All you need is a plausible means of time travel (some sort of wonder gizmo) and a satisfying story in which the time travel contributes to the plot without overstretching it. People like time travel stories so will forgive a lot in their pursuit of an enjoyable read.

As for the science of time travel? I can understand (via Einstein) that time travel forward (for humans rather than just subatomic particles) is possible. I don't think it's possible backwards though (in any way we can understand) because if time travel backwards was possible, then someone would have invented it in the future and we'd know about it now. The instant someone in the future invented time travel then everyone else throughout all time would have access to all time. It'd be total chaos. But it's not. So travel to the past is not possible.

I am The Dark One...I have spoken.


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## Ruby (Mar 15, 2014)

Gryphos said:


> No, I said that it wouldn't be possible in the real world, but in a fantasy story you could have it and just put it down to magic.



Hi Gryphos, sorry I didn't understand as on your original post there must have been a typo and you put "matter" instead of "magic".


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## Ruby (Mar 15, 2014)

The Dark One said:


> I think most of this is way too complicated for a story. All you need is a plausible means of time travel (some sort of wonder gizmo) and a satisfying story in which the time travel contributes to the plot without overstretching it. People like time travel stories so will forgive a lot in their pursuit of an enjoyable read.
> 
> As for the science of time travel? I can understand (via Einstein) that time travel forward (for humans rather than just subatomic particles) is possible. I don't think it's possible backwards though (in any way we can understand) because if time travel backwards was possible, then someone would have invented it in the future and we'd know about it now. The instant someone in the future invented time travel then everyone else throughout all time would have access to all time. It'd be total chaos. But it's not. So travel to the past is not possible.
> 
> I am The Dark One...I have spoken.



Hi The Dark One, and thank you for your advice.  I've been told that Time Travel stories always contain plot holes.

I don't want to abandon writing this book, so I'm going to focus on structuring the plot and, as Devor said (above), the characters don't have to time travel much.  It's quite a humorous book, probably MG/YA and contains magic, some steam punk and time travel with a couple of would be assassins lurking in the background. Hopefully, the readers will suspend their disbelief as for other genres of Fantasy.


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## Steerpike (Mar 15, 2014)

If ideas about the time line splitting were true, then we wouldn't know about backwards time travel until we reached the date it was invented in our time line and wouldn't always know about it. Another problem solved by that approach.


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## psychotick (Mar 15, 2014)

Hi,

Just to add to the butterfly effect - it's actually far more powerful in terms of change than most people seem to realise. Remember in the real world tiny things can have huge impacts - and that doesn't mean in rare circumstances. It appliesto a great many things. So say you go back in the past a thousand years. You're there only for an hour or so, and you try to remain more or less unnoticed. So you do nothing really. Maybe you walk through a market and nod at a few people.

Now everyone you nodded to is changed by the encounter - in the most minor way. Some of them may wonder who you were and take a moment to think. That moment may make them late home by thirty seconds. They then go and make love to their wives thirty seconds later than they woul have. (Or maybethey have other things to talk about at home because of that nod - something like "Saw a strange guy in the market today!) Regardless fifty million sperm race to fertilise an egg and there is one winner. (Or maybe there is no winner when there shoul have been, or is a winer when there shouldn't have been.) But why would it be the same sperm that succeeds? No reason at all. So in nine months a completely different baby is born. Then that baby lives an entire life changing the lives of everyone he encounters in completely unexpected ways and every baby born after that who has any connection tohim is a different baby. Fairly soon the entire world is filled with completely different people simply by this mechanism alone. Just from a nod.

And there's no actual way to stop this happening.

Cheers, Greg.


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## Devor (Mar 15, 2014)

psychotick said:


> And there's no actual way to stop this happening.



To bring it back to sci-fi writing, it's a pretty common trope to just say "the universe corrects itself for the little stuff" and handwave it.  That kind of statement has the purpose of showing the reader that you know what you're aware of the real world details, even if you're ignoring them, and helps readers to move beyond the disbelief.  It creates the illusion that there's an in-book rational explanation, even if it's really just that statement.


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## The Dark One (Mar 15, 2014)

That's right. People always accept the wonder gizmo or the magic crystal, and you have to screw it up pretty badly to reboot their disbelief.


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## psychotick (Mar 16, 2014)

Hi,

The problem is that I can't simply accept a statement like that at face value. Time repairing itself always seems to me like someone is saying that time is some sort of living thing - and that crosses the boundary between sci fi and fantasy.

And there are so many paradoxes to consider. Ignoring the shooting your own grandfather one, one that I like is failure of conservation. To give an example say time travel is invented tomorrow, where does everyone set as their destination or one of them - the crucifiction. But that's everyone until presumably the end of time. Which means that instead of two thousand people there's potentially an infinite number all arriving there at the same moment, and perhaps fracturing the Earth's crust or even starting a singularity. That would have gone down in our history books!

Though to be fair I did actually write a time travel novella in which this same paradox was used as an explanation for the begining of the universe. I.e. everyone turned up in their time machines at the same place and tie, and hey presto - big bang!

Cheers Greg.


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## Devor (Mar 16, 2014)

psychotick said:


> The problem is that I can't simply accept a statement like that at face value. Time repairing itself always seems to me like someone is saying that time is some sort of living thing - and that crosses the boundary between sci fi and fantasy.



That's not the only conclusion.  If time travel were possible, it would imply what we already think we know, that all moments exist simultaneously.  That would mean that time is part of a complicated system, and most complicated systems adjust to survive small changes.  If the future already exists, then the future would resist that change, sort of like a type of friction.  Ripples lose energy as they move away from their source.  So could the butterfly effect.




> And there are so many paradoxes to consider.



That goes back to a main problem with most science fiction - the science being depicted is often an impossibility.  Our technological capabilities are increasing at an exponential rate.  But exponential growth ends by crashing into a ceiling.  Where?  I have no idea.  But it's an inevitability that some things will be scientifically impossible.  Time travel is almost certainly among them.  Any time travel story runs the risk of paradoxes, and bad science, and more, because it's not science.  It's fiction.


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## Penpilot (Mar 16, 2014)

Devor said:


> Any time travel story runs the risk of paradoxes, and bad science, and more, because it's not science.  It's fiction.



This reminds me of a scene I once saw in Dr. Who. One of his companions ask him about the butterfly effect. His response was something to the effect, "Where's the fun in that?"

One of the most highly rated movies in a while, Looper, was a time travel story. It had an awesome story, but a massive plot hole that you could throw all of space and time into. The writers knew this and all they did to address it was have a character say something to the effect, "If you want to talk about time travel we'll be here all day drawing diagrams," effectively hand waving it away.

Time travel stories are fun, regardless of it the science is possible.

If anyone wants to check out a time travel movie check out Primer. It deals with the creation of paradoxes, and it'll make your head spin when you think about it. And if you blink, you'll miss something, and you'll realize what you think you know is wrong. Till this day, I'm not sure if I fully understood everything that happened in the movie. Don't get me wrong it's very watchable, but you have to be paying attention to pick up on the nuances because they don't spoon feed you the info.


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## Ruby (Mar 16, 2014)

psychotick said:


> Hi,
> 
> Just to add to the butterfly effect - it's actually far more powerful in terms of change than most people seem to realise. Remember in the real world tiny things can have huge impacts - and that doesn't mean in rare circumstances. It appliesto a great many things. So say you go back in the past a thousand years. You're there only for an hour or so, and you try to remain more or less unnoticed. So you do nothing really. Maybe you walk through a market and nod at a few people.
> 
> ...



Hi psychotick, thanks for posting this. This would make a very good plot for a time travel book. Maybe YOU should write it. I'd like to read it! 
But seriously, isn't "real" life a bit like this anyway? Everything that happens changes you, and if you are late or early you will have a different journey/experience.


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## Ruby (Mar 16, 2014)

psychotick said:


> Hi,
> 
> The problem is that I can't simply accept a statement like that at face value. Time repairing itself always seems to me like someone is saying that time is some sort of living thing - and that crosses the boundary between sci fi and fantasy.
> 
> ...



Hi psychotick, ah, so you have written a book about time travel!

If lots of time machines cause a Big Bang, can you explain how in a recent Doctor Who special, there were three versions of the TARDIS in one scene and there wasn't a paradox or a Big Bang in sight?

In my book, one of the characters takes his grandfather into the future to build the time machine. There must be a paradox there, I guess.


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## psychotick (Mar 16, 2014)

Hi Ruby,

Unfortunately I gave up on Doctor Who after Tom Baker left. He is for me the quintessential doctor. But yes there are endless paradoxes in the show and they are never addressed properly - probably because they can't be.

And yes there are paradoxes in going to the future as well. So let's say your character does as you say and goes to the future to pick up a time machine from his grandson? Let's say he goes a hundred years into the future. Then he goes back and lives out his normal life in the present. At every stage of his life in the present he is changed because of his trip to the future. And that change must affect his behaviour and so in turn affects the world around him. So how does he live a life in the present that is exactly as it should have been had he not gone to the future?

The answers are of a course a philosophical grab bag. The first one is that he doesn't. He lives a different life, and that life is in fact the one that leads to the future where he can find a future in which his past self will arrive (have arrived? Tenses are problematic here.) But that leads us straight into destiny (not the predictions of greatness type.) It means that everything he does from the point at which he left until the point in the future at which he arrived is completely predestined. Not just him but everyone else as well. In short there is no such thing as either free will or chance.

The next choice is the parallel worlds options where, the world split at the point when he travelled to the future. Thus he went to "A" future but not necessarily "THE" future. So that future will not have to exist later. This runs into a different problem, one of energy. If every time I walk down a street and turn right instead of left a new possible universe is created, where did the energy forthat come from? It certainly didn't come from me turning in one direction. And we are talking about the creation of an entire universe here.

And the third option is the one touched on by Devor. The so-called B series of time. In the B series time does not change, but rather we move through it. It's rather like reading a book, where the present is the page your reading, but most importantly every other page in the book - those you've read (the past) and those still to read (the future) exist in exactly the same way that the present does. Now in this scenario time travel is paradox free. The reason is simply that if I take out my little red pen and start rewriting some of the pages from the past or the future, it makes no difference to the page I'm on. They are all already written.

However there are consequences too, and the biggest one is that cause and effect no longer applies to anything. For example if on one page I throw a ball and on the next it is flying, there is no actual reason for it to be flying save that someone wrote that it was. Because every page - every present - is completely indipendant of every other one. So if I change the previous page such that I no longer threw the ball, in the next page it still flies. Which simply means that the reason the ball flies has nothing to do with anything done on a previous page.

Cheers, Greg.


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## Reaver (Mar 16, 2014)

I'm a huge fan of science fiction but I avoid writing anything with time travel for all the reasons mentioned above. That and quantum physics.


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## Noma Galway (Mar 16, 2014)

My personal opinion on time travel is that time is stationary. We can move about in time and nothing will change, because time knew we were going to move about in time. Everything is fixed, to use a Doctor Who term. No moment is in flux.


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## Ruby (Mar 16, 2014)

psychotick said:


> Hi Ruby,
> 
> Unfortunately I gave up on Doctor Who after Tom Baker left. He is for me the quintessential doctor. But yes there are endless paradoxes in the show and they are never addressed properly - probably because they can't be.
> 
> ...



Hi psychotic, I gave up on Doctor Who when the Daleks learnt how to fly and climb stairs! I have a copy of the first Doctor Who book, ah, those were the days!

The book I'm writing (or not, more like procrastinating ) mixes magic, time travel and science. The time traveller is a magician who turns up in the wrong year to bring the MC back to the future, but she is still living in her own time and hasn't time travelled yet. She hasn't met him before and thinks he's deranged.  So while he's trying to fix the machine, he hooks up with his Great Grandfather, who's worked with him in the future. He also finds another prototype of the time machine there that someone else has stolen. So, how many paradoxes have I got so far? And the MC hasn't even time travelled yet!  This is only part of the main plot.
Btw this is just the prequel to my other WIP where the MC is stuck in the future. It's also complicated by having to write everyone's ancestors and descendants and work out the maths of how old everyone is. Plus the historical research necessary for writing about the past. But the time travel paradoxes are the most complicated aspects of this plot.

So far I have about 100 characters for the two books, including a couple of rabbits and a poodle used in magic acts.

I don't know whether to abandon this and write some chick lit with maybe three characters and an unrequited love story.

Having said that, I do like what I've written so far, it's just needing to know what rules will work. I'm reading a couple of time travel stories now as research.
Thanks for your help! 

((Btw Sorry I haven't thanked anyone for their interesting post today, but I seem to have run out of those at the moment!  ))


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## Ruby (Mar 16, 2014)

Reaver said:


> I'm a huge fan of science fiction but I avoid writing anything with time travel for all the reasons mentioned above. That and quantum physics.



Hi Reaver, thank you for this inspiring post! Yes, well, even I haven't attempted putting quantum physics in the WIP. Although, come to think of it, I may have to as the MC is supposed to be doing scientific research into kinetics.


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## Ruby (Mar 16, 2014)

Noma Galway said:


> My personal opinion on time travel is that time is stationary. We can move about in time and nothing will change, because time knew we were going to move about in time. Everything is fixed, to use a Doctor Who term. No moment is in flux.



Hi Noma, thanks.  So I can just disregard all the above theories?


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## Noma Galway (Mar 16, 2014)

Well no...that wasn't what I meant. I just wanted to add my two cents. I thought that would be the way to write about it without paradoxes. Though my theory lends itself to predestination... :/


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## Ireth (Mar 16, 2014)

Noma Galway said:


> Well no...that wasn't what I meant. I just wanted to add my two cents. I thought that would be the way to write about it without paradoxes. Though my theory lends itself to predestination... :/



But if every moment is fixed and nothing can change, then why bother with time travel at all? Sightseeing seems about the most you could do with it in that case.


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## Noma Galway (Mar 16, 2014)

Well, see, time would be prepared for the change. The travelers wouldn't know it. Like someone who went back to stop Hitler from coming to power would be the cause of his coming to power. I think that analogy was mentioned earlier.


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## Ruby (Mar 19, 2014)

Hi, the main problem with my time travel plot, as I see it, is keeping track of who knows what in each scene, whether they have met before and avoiding obvious paradoxes. Apart from that, easy peasy!


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## Steerpike (Mar 19, 2014)

Noma Galway said:


> Well, see, time would be prepared for the change. The travelers wouldn't know it. Like someone who went back to stop Hitler from coming to power would be the cause of his coming to power. I think that analogy was mentioned earlier.


  Is there still going to be a paradox, though, that if someone goes back in time and announces they did so (or even proves it), but they weren't there the first time around, then things have changed. Otherwise, if there is any time travel at any point, then there would always be time travel (which also seems paradoxical). And you've still got issues with conservation of mass and energy, right?


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## Devor (Mar 19, 2014)

psychotick said:


> And the third option is the one touched on by Devor. The so-called B series of time. In the B series time does not change, but rather we move through it. It's rather like reading a book, where the present is the page your reading, but most importantly every other page in the book - those you've read (the past) and those still to read (the future) exist in exactly the same way that the present does. Now in this scenario time travel is paradox free. The reason is simply that if I take out my little red pen and start rewriting some of the pages from the past or the future, it makes no difference to the page I'm on. They are all already written.
> 
> However there are consequences too, and the biggest one is that cause and effect no longer applies to anything. For example if on one page I throw a ball and on the next it is flying, there is no actual reason for it to be flying save that someone wrote that it was. Because every page - every present - is completely indipendant of every other one. So if I change the previous page such that I no longer threw the ball, in the next page it still flies. Which simply means that the reason the ball flies has nothing to do with anything done on a previous page.



That doesn't sound like what I was talking about.

What I'm talking about is a way to minimize the butterfly effect.  In normal time, A leads to Z.  But you go back in time and change A into @.  Instead of changing everything, the future creates a friction that resists to minimize the change.  Somehow @ still leads to Z.  Maybe B has to become $ and C becomes &, but somewhere along the way the letters manage to come back, depending on how big the change was.

It's kind of like the original time travel story where he goes back to save his girl, but finds that she still dies, just a different way.  The future resists your effort to change.  The Tenth Doctor tries to save everybody's life in a fixed point, but the future resists, the woman kills herself, and he manages to change exactly one line in the document.  The future already exists and resists your efforts to change it.

You can take this principle as far or as little as you want.  Maybe saving a person is tough, but killing might have a bigger change.  Maybe I can't change the distant past, but I can go back to yesterday to fix something big, and I can get away with it because the future already knew I was doing it.

Or maybe "the universe adjusts" is just enough to explain away the butterfly effect, and I can change whatever else I can manage.


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## Ruby (Mar 19, 2014)

Hi, 

I keep thinking that everything's sorted in the plot and then another paradox turns up! Such as, how much the other time travellers know about the MC in the future when they meet her in the past before she goes to the future. 

How do I know where the story even begins?  

Ps Can anyone recommend a good time travel book to read as research?


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## Queshire (Mar 19, 2014)

A person's subjective time remains linear even as they weave in and out of the objective timeline. Five minutes ago for you is five minutes ago even if five minutes ago you where in 2121. Basically they would know as much about your MC as they learned from when they met the future version of your MC. Now, how much that would actually be is something that you have to decide for yourself. It's one of the main challenges of a time travel story. You need to keep the composition of the entire piece in mind from the beginning. You can't seat of your pants it, just going from cause to effect like a series of dominoes, as with time travel, a later effect can go back to be an earlier cause.


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## Ruby (Mar 20, 2014)

Queshire said:


> A person's subjective time remains linear even as they weave in and out of the objective timeline. Five minutes ago for you is five minutes ago even if five minutes ago you where in 2121. Basically they would know as much about your MC as they learned from when they met the future version of your MC. Now, how much that would actually be is something that you have to decide for yourself. It's one of the main challenges of a time travel story. You need to keep the composition of the entire piece in mind from the beginning. You can't seat of your pants it, just going from cause to effect like a series of dominoes, as with time travel, a later effect can go back to be an earlier cause.


Hi Queshire,

Yes, I agree with you.

 There was another problem re my plot which I discussed on another thread: does a character age if they're taken to the future, live there for 60 years and then return to around the time they left? I still haven't resolved that one. Of course, if she doesn't age that would affect the second book and if she does, it would change the first. So it's either going to be a happy ending or horror!


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## Queshire (Mar 20, 2014)

Author's choice. I've read one book that has time travelers' only age when they're in their native time frame, in Narnia though they live to grow up in Narnia when they come back to Earth they turn back into kids, I don't think it's spelled out, but I'm pretty sure that in Doctor Who you keep aging like normal regardless of when you are so yes, they would be an old lady if they returned after spending 60 years in the future, or, hey, maybe with the way time travel works the moment you time travel you become unstuck in time, immortal and unchanging forever. That could be interesting.


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## The Dark One (Mar 21, 2014)

Listen, Billy Pilgrim has come unstuck in time.

Poo-tee-phweet?


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## Ruby (Mar 21, 2014)

Queshire said:


> Author's choice. I've read one book that has time travelers' only age when they're in their native time frame, in Narnia though they live to grow up in Narnia when they come back to Earth they turn back into kids, I don't think it's spelled out, but I'm pretty sure that in Doctor Who you keep aging like normal regardless of when you are so yes, they would be an old lady if they returned after spending 60 years in the future, or, hey, maybe with the way time travel works the moment you time travel you become unstuck in time, immortal and unchanging forever. That could be interesting.



Hi Queshire,
Yes, I think the Narnia one doesn't really work. How can they grow up, live as adult monarchs in Narnia for many years, and then suddenly revert to being children going to school on a train? They wouldn't be children any more, would they? I mean, mentally.

My MC does age in the future. I think she will have to still be old when she travels back. 

Doctor Who has a clever plot device in that he changes physically every time a new actor plays the role. So he can appear older or younger. 

I must admit I rarely watch Doctor Who these days. Not since David Tennant left.  I prefer all the very old series. I think the modern special effects spoil it. I didn't like the Christmas special either. I think it's been " dumbed down".


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## Steerpike (Mar 21, 2014)

The Dark One said:


> Listen, Billy Pilgrim has come unstuck in time.
> 
> Poo-tee-phweet?




And so it goes...


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## Jabrosky (Mar 21, 2014)

When I was a kid, I loved time travel stories. Especially when the destination was the Mesozoic, and most of all Late Cretaceous North America. As I like to say, everything is better with dinosaurs.

That said, I seldom bother with time travel in my own writing. Even if you could somehow have-wave the paradoxes away, the neat thing about fantasy world-building is that there's nothing preventing you from juxtaposing human characters with dinosaurs or other prehistoric wildlife in the same time period.


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## Queshire (Mar 21, 2014)

Ruby said:


> Hi Queshire,
> Yes, I think the Narnia one doesn't really work. How can they grow up, live as adult monarchs in Narnia for many years, and then suddenly revert to being children going to school on a train? They wouldn't be children any more, would they? I mean, mentally.
> 
> My MC does age in the future. I think she will have to still be old when she travels back.
> ...



When you say it doesn't really work that means that it breaks your willing suspension of disbelief. Willing suspension of disbelief means that the reader makes it a point to ignore the impossible things in a story in order to enjoy the story. Take magic for example, it doesn't exist in real life, but we don't mind because it helps the story. However willing suspension of disbelief only goes so far and if you exceed how much a reader is willing to tolerate these impossible things then you're going to have a bad time as a writer.

One thing that writers can do to make sure that they don't break a reader's willing suspension of disbelief is to make their work follow some sort of internal rules or logic even if they aren't the real world's rules or logic. For example, Narnia has talking lions and being able to travel to a different world through a wardrobe. In that context having the kids aged down without anything weird happen to them as a result of those years doesn't seem as strange.

So it doesn't matter how you do time travel or magic or whatever so long as it makes internal sense. (sort of. There's still a limit to all things and if you go too far not even being internally consistent can save you.)


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## Ruby (Mar 21, 2014)

Queshire said:


> When you say it doesn't really work that means that it breaks your willing suspension of disbelief. Willing suspension of disbelief means that the reader makes it a point to ignore the impossible things in a story in order to enjoy the story. Take magic for example, it doesn't exist in real life, but we don't mind because it helps the story. However willing suspension of disbelief only goes so far and if you exceed how much a reader is willing to tolerate these impossible things then you're going to have a bad time as a writer.
> 
> One thing that writers can do to make sure that they don't break a reader's willing suspension of disbelief is to make their work follow some sort of internal rules or logic even if they aren't the real world's rules or logic. For example, Narnia has talking lions and being able to travel to a different world through a wardrobe. In that context having the kids aged down without anything weird happen to them as a result of those years doesn't seem as strange.
> 
> So it doesn't matter how you do time travel or magic or whatever so long as it makes internal sense. (sort of. There's still a limit to all things and if you go too far not even being internally consistent can save you.)



Hi Queshire,

Oh, I totally agree with you. When I read the Narnia books as a child, I suspended disbelief and it seemed right that the children reverted to being children again. As a child, I was upset that they became adults in Narnia. However, when I reread the books as an adult, I found this a peculiar aspect of the plot.

On the other hand,  C S Lewis is consistent in that he allows time spent in Narnia to be no time in our world. But then he's telling a story of magic, not time travel. He also invented the wood between the worlds in The Magician's Nephew, so they could travel to other worlds using magic rings, and there are many biblical references in the book, too. Again, children would not notice the allegories in the book or the parallels with Adam and Eve and the fact that evil enters Narnia with the witch as soon as the new world is created.

You are right in that you need to establish the rules for your own unique book.


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## Ruby (Apr 13, 2014)

Hi,

Today the MC's little dog was murdered. I wanted her to be resurrected but realised if time travel was used to save her then all of the events of that scene would be nullified. This would have meant discarding the newly evolved relationships between three of the main characters, not to mention the would-be assassin who's stalking the MC.

So the time traveller had to use magic, science and a little steam punk instead.

It seems that the best way to write a time travel story is to keep the actual time travel to a minimum.


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## Queshire (Apr 13, 2014)

Did anyone actually see the dog die? If not a time traveller could swoop in at the last moment and rescue it without any paradox. Mind you, there would be no body in that case unless the time traveller drops provides an alternative body or they wouldn't see the body at all to begin with; for example falling off a cliff, being burned to ash, etc and so on.


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## Svrtnsse (Apr 13, 2014)

You could also use the dead dog as source of ethical dilemma. Will your MC use time-travel to save the dog and risk the paradox or will she soldier on without her dog so as to not put the world at an unnecessary risk.


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## Ruby (Apr 14, 2014)

Queshire said:


> Did anyone actually see the dog die? If not a time traveller could swoop in at the last moment and rescue it without any paradox. Mind you, there would be no body in that case unless the time traveller drops provides an alternative body or they wouldn't see the body at all to begin with; for example falling off a cliff, being burned to ash, etc and so on.



Hi Queshire,

Thank you for this.

No one directly saw the dog die but the MC was in the vicinity. Someone else finds the dog and is almost murdered, too. He is going to become the MC's love interest as a result of this scene, although previously they hated each other! (Remember Pride and Prejudice - although there was no time travel in that, that I can recall, anyway.  ) Then the time traveller appears to save the day and the dog. He is no common time traveller, you see. The MC has not experienced time travel at this point in the story and thinks he's mad!)

So, if the time traveller revived the dog by taking the scene back in time, say one hour, my useful plot progression/character development would disappear. Also, don't forget there is an assassin lurking nearby!

I was going to be ruthless and let the dog die, but the MC needs it in her act and I'd have to write about her buying another dog and training it which would be tedious.

I've found another solution using steampunk and magic.

This is turning into an interesting book. I'm a Plantser, you see. That means Pantsing and then finding a plan and a structure. I'm looking forward to finding out what happens next.


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## Ruby (Apr 14, 2014)

Svrtnsse said:


> You could also use the dead dog as source of ethical dilemma. Will your MC use time-travel to save the dog and risk the paradox or will she soldier on without her dog so as to not put the world at an unnecessary risk.



Hi Svrtnsse,

Yes, you're correct: time travel now would result in a paradox. The MC will do this later, but to save a human being.

I was worried that time travelling at this stage would create a very complicated plot. There would have been two time lines. I can't begin to tell you how difficult this book is to write! However, it's beginning to make sense! Yes, of course it is...


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## Ruby (Apr 14, 2014)

Hi,

The time traveller says to the MC, "Your dog is as dead as a Dodo!"

Would the MC be confused to hear this, or would this expression have been used in Victorian times?


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## Devor (Apr 14, 2014)

Ruby said:


> The time traveller says to the MC, "Your dog is as dead as a Dodo!"
> 
> Would the MC be confused to hear this, or would this expression have been used in Victorian times?



I'm not sure, but I wouldn't use it.  It was a big deal when the dodo went extinct, so maybe, but we only talk about it because it was in Alice in Wonderland.  I wouldn't risk it.

((edit))  Apparently Alice was written in 1865, so before then, no, after then, yes.


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## Ruby (Apr 14, 2014)

Devor said:


> I'm not sure, but I wouldn't use it.  It was a big deal when the dodo went extinct, so maybe, but we only talk about it because it was in Alice in Wonderland.  I wouldn't risk it.
> 
> ((edit))  Apparently Alice was written in 1865, so before then, no, after then, yes.



Hi Devor,

My story begins in 1899. The time traveller is from the 20th/21st Century.


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