Time travel

[Queshire]

I'm planing on including time travel as, if not a major part, but a big part in my series. Admittedly this won't come into play until later in series, but I figure better to get it thought out now. I don't think I have to say this but Time travel is hard to do right, it makes your head hurt just thinking about it. Call me a masochist, but that challenge appeals to me, plus, I think I can do time travel in a way that, if not better, makes more sense. Here's what I have so far, I'd like any input you might have.

1) For the most part, it's better to think of time travel as not actually traveling through time, but traveling to an alternate reality that's exactly the same as yours except it's however far futher or behind your own reality. That's not quite the truth, but it works for the most part and simplifies things immediately.

2) Your personal past is absolute, but your future has yet to happen.

3) This means that Paradox doesn't exist. If you go back and kill your grandfather, you don't poof out of existence, the alt-you that would have been born in that timeline simply wouldn't be.

4) It also means that Predetermination doesn't exist. Don't think you're invulnerable just because you talked to your future self, just because that version of you, future-alt-you, lived that long doesn't neccesarily mean you have to.

5) Futhermore, just because you got help from the future, future-alt-you came back and beat up the monster about to chomp you or came back and left just the tool you need in just the location you need it, doesn't mean you have to go back and do that later one.

6) However, it's generally considered a wise idea to go out of your way to close time loops. If you're the type of guy that doesn't go back to help past-alt-you when he needs it, then the future-alt-you probably won't be the type of guy to help you next time you need it.

7) What happens if you go back to the future after changing the past depends on your type of time travel, if you go back to your orignal timeline then nothing will have changed, though you can also trace the timeline you made the changes in to find a future where those changes are in effect and travel to that timeline.

8) Likewise, an equivalent amount of time will have passed in your original time, it's possible to return to just after you left, but that would be another timeline and not your original one.

9) Generally, you don't have to worry about alt-you in those timelines, as with extremely rare exceptions, aproximately as rare as all the stars in the sky going supernova at the same time, they'll do the exact same thing you did, and so on for infinity.

10)With all that you might think that some random joe might go back and completely screw with history, however there's two problems with that;

10a) There's litterally an infinite to the infinite power number of different timelines, a lot of which end up completely identical. You might have just lucked out.

10b) The fact that they haven't messed with the timeline so far makes it likely that your particular timeline was labeled a Historical Perserve by the Time Police.

11) The time police are a multi-timelinal organizationd dedicated to prevent the abuse of time travel. They aren't dedicated to making history go the way it's supposed to, but simply that it progress unmolested by time travellers.

12) Timetravellers can travel to historical perserves, and even interact with history, but the laws enforced by the time police limit the spread of future knowledge and tech to acceptable levels, you can play around with time travel so long as you're responsible and don't end up severely screwing stuff up.

13) The time police also work on other abuses of time travel, such as breaking infinite loops, stopping a time travel capable person from going back to kill their boss every time they have a bad day then jumping back to their original time line where that never happened, and so on.

14) If someone DOES screw up time, the time police will work to cover it up to the best of their ability, culminating in wiping the memories of everybody involved if they have to.

15) However, the time police have to cover A LOT of timelines, and hate having to fix others messes, so if you can fix it yourself, you're better off doing so.

So, in summary, time travel is possible and it has very few consequences except for getting the time police pissed at you. Any questions, comments, or suggestions guys?

 

[TWErvin2]

Just to play the devil's advocate role:

Why would the time police even bother, if everytime someone goes back in time and changes it, they just create a new timeline/alternate reality (#1 & 3), which wouldn't affect the other timelines.

#12 doesn't seem enforceable. With all of the multiple diminsions and timeines with time travel, it'd be impossible to keep track of what someone did or didn't do, unless it's going to be a version of the time cops arrive just before the time traveler arrived and stop him from doing what he was going to do...which means what would stop him from going back a bit furhter and screwing up what the time time cops were going to do, or work with a partner who would appear just before him, etc. And again, way would it matter if there are an infinite number of timelines out there, unfolding in an infinite number of ways, which could be branched off again and again every time someone shows up. Becuses really, any minor thing done could potentially have a major impact.

I know it's an old story, but "A Sound of Thunder" by Ray Bradbury is relevant to the point I'm making.

 

[Steerpike]

This one seems to be problematic:


8) Likewise, an equivalent amount of time will have passed in your original time, it's possible to return to just after you left, but that would be another timeline and not your original one.


So if you travel to another timeline, spend a decade there, and then go back to your original timeline, a decade will have passed there as well. But why can you not go back to just after you left? You're not causing a paradox. You're not re-entering a timeline in which you already exist? There doesn't seem to be any explanation as to why this would force an alternative timeline.

To me, going back to the past or to other timelines where you already exist...it makes sense that those things would force a new timeline to come into being. But I'm not following you on #8.

Also, with number 11 - since timelines always split when people go back and impact them, what's the need for the police. The traveler isn't impacting anything that didn't come about as a result of their own time travel action, right?

Those are my thoughts.

EDIT: Ninjae'd on my second point by TW!!

 

[Queshire]

Ha~~~ The questions you guys come up never ceases to amaze me... Maybe I'm overthinking this? I mean, essentially it boils down to;

1) Time travel is possible.
2) Paradox and predetermination is a myth.
3) While your personal history is fixed, your future is in flux until it actually happens.
4) While you don't have to close time loops it's a good idea to do so.
5) Don't interfere in history too much or the Time popos will come get you.
6) And if they don't, the Time Roaches will.

Aside from that, does the why really matter? I mean, in my story, the main time travelling character is the equivelent of a foreign exhange student, a temporal exchange student. He or she (I'm still working on this character) doesn't neccesarily need to know the principles behind it.

But, to answer your questions, first off, time traveling doesn't -create- a new timeline / alternate reality, while there's an infinite to the infinite power of them, they existed before they get travelled to. The time police protect them because otherwise they wouldn't be time police! I mean, sure there's basic human decency, and unmonitored time travel could easily result in an army poised to attack the time zones they care about, but really, I just came up with them as a detterent to messing with time.

The future knowledge / tech ban works about as well as anti-littering laws in natural wildlife preserves. It's hard and they're not always good at enforcing it, but it has to be done.

8 was logically required by how I described time travel working, you're not travelling through time, but to alternate realties that are identical to your reality except futher along or behind your reality's time. That is the ONLY difference, though, in all other ways it'd be identical.

Again, time doesn't split, but also, just because it's an alternate reality doesn't mean the people there are any less living and breathing then those in your home reality / time, hell to them, YOUR reality is the alternate one.

 

[Sheilawisz]

Queshire, my personal theory about travels to the past is that you would really travel to a totally separated reality, another world in another universe that just happens to be very similar to the past of your own world: Then whatever that you do cannot affect your original world at all, and so paradoxes do not come into existance =)

In my stories, my Mages can shatter reality itself even without silly paradoxes, but they never travel to the past and the reason that I give is this: The past is not there, it does not exist, it's not a place that you can travel to or change in any way...

I think that travels to the future are way more interesting!!

 

[BeigePalladin]

But, to answer your questions, first off, time traveling doesn't -create- a new timeline / alternate reality, while there's an infinite to the infinite power of them, they existed before they get travelled to. The time police protect them because otherwise they wouldn't be time police! I mean, sure there's basic human decency, and unmonitored time travel could easily result in an army poised to attack the time zones they care about, but really, I just came up with them as a detterent to messing with time.

so the time police exist as an orginization for the simple sake of existing as an orginization? especially since you already said that every possible outcome of everything already exists as a paralel world, which would mean that for everything the time police do stop would equally have a variant where they did not.

especially since you admited you can't mess with time (well, you can, but since it would always have happened already it would be easier to travel to an alt.reality where you in the past already made the change and skipped a step) meaning they become doubly irrelivant since by your own admission they can do nothing.

 

[Ravana]

A few general comments on time travel—numbered, though the numbers have nothing to do with the ones in your original post.

(1) Time travel is inherently paradoxical—at least where it's not completely trivial. If all the traveler can do is observe, no problem… at least for those interested in researching history; for the author, the "problem" will be justifying the inclusion of time travel at all in such circumstances. While it would be possible for a person to travel in time without creating (major) paradoxes, by being extremely careful with one's actions, let's face it: the people most likely to want to time travel will be the ones who want to make changes, and eventually one of them will… paradox.

(2) The only way to avoid paradox is to make history immutable. And since all of time will be someone's history, this means that all time up to the point of the last intelligent being at the end of the universe must be immutable… in other words, the only way to avoid paradox is predestination. Worse, with an infinite number of timelines realizing all possibilities, predestination gets built in regardless—because all possible outcomes are guaranteed to occur somewhere.

(3) Travel to "alternate timelines" is not time travel—not even if you travel to a different point in time in that alternate timeline than the one you started from in your own. It may seem like time travel from the point of view of the traveler, but he's actually traveling to a different dimension (timeline), not another point in time in his own. Indeed, he isn't even necessarily traveling to "a different point in time" in that alternate line, because, positing infinity, there will be alternate timelines where things simply happened that much faster (or slower), and thus will be that much farther along (or less so), than his own line. Likewise, "returning" to "his own" timeline with the amount of time he was away having elapsed is irrelevant, since he could just as easily "return" to a timeline where all else was identical up to the point of his departure, and "return" to exactly the point in time he departed from the instant after his "double" in that universe departs on his own trip. How would the traveler (or anybody else) know the difference? (And, of course, the "double" could "return" to the same point in the original traveler's timeline—or a third timeline, et cetera—and he'd never know the difference, either. In fact, this sort of thing might be done deliberately.)

(4) As BeigePalladin pointed out, having an infinite number of timelines which realize all possibilities makes the whole exercise pointless: no matter what you do (or don't), the opposite will happen somewhere else. So who cares? The only thing that makes time travel interesting is if you can alter things—in meaningful ways.

(5) The only way to make time travel "work" is to ignore (1) for the sake of the story.

In fact, you've already built paradox into your structure, though I'm guessing you didn't realize it. While you posit an infinite number of timelines, you have rejected (properly, in my view) the notion that "making a change" creates a new timeline. But your (original) item #3 indicates that it is possible to "go back and kill your grandfather" (thereby guaranteeing that the traveler won't be born in that "alternate" timeline), while your item #4 says there's no predestination. This combination means that it is possible for someone—probably not the traveler in question—to go back and kill that grandfather in every timeline where that grandfather exists, thereby erasing the descendant in all timelines. Yes, this would hypothetically involve an infinite number of such kills, but that does not make it impossible: there would also be an infinite number of "doubles" of the postulated assassin as well, after all.

But—your item #2 says that a person's past is immutable; my item #2 points out that all history is someone's personal past, which means that all history is immutable… predestination. Contradiction. And the only escape from that contradiction is to allow history to be mutable—which means allowing paradox.

As you say, time travel is difficult to do right. I'd go one step farther: it's impossible to do "right." The problems are inescapable. The only way to write good time travel is to simply ignore one or more of them—at which point you're back down to "difficult." Trying to provide an explanatory mechanism for time travel is similar to providing one for magic: eventually, you get down to hand-waving, i.e. "it works because I'm the author and I say it works."

I'd recommend tracking down Fritz Leiber's Changewar and The Big Time: both are in the same setting, the first a collection of short stories, the second a novel. Start with the short stories, in particular "Try and Change the Past." (On the other hand, the original, serialized version of The Big Time is available at Project Gutenberg, so it's available for free.) Also, Robert A. Heinlein's short story "—All You Zombies—" is, in my opinion, indispensable reading for anyone writing time-travel fiction… especially if closing loops is part of your interest.

•

P.S. I find magic more plausible than time travel, which I regard as thoroughly impossible. You know how I know that? Because if it were possible, someone would have already invented it. Think about it.…

 

[Queshire]

@Sheilwisz: So since the past doesn't exist then they can't go back once they've travelled to the future?

@BeigePalladin: Yep, pretty much. The infinite nature of the timelines would also mean that the time police HAD to exist, regardless of how futile it would be. Mostly though, you wouldn't think about it too much, you don't mess with the time police, they're scary. Also, not everybody that time travels knows the truth about time travel, so they don't know about skipping steps or what not.

@Ravana:
1) This is not news to me, I explained why paradox doesn't really matter. Stoping people that want to change the past is one of the Time Police's duties.

2) Only your past matters, others don't, likewise other's past's are immutable for them, while yours doesn't. Do you know the saying; "I think, therefore I am"? The guy that came up with that came up with it after he tried to find something that can be proven 100% without a doubt, and ultimately the only thing he found was that there was SOMETHING doing the questioning. Everything else could convivably be some grand illusion. Basically, this means that personal history trumps other's history.

3) Nope, no it is not time travel. It's close enough though! Technically it's not traveling to alternate realities, but the differences between the two would require a post-technological-singularity mind to have any hope of understanding. Mainly that just gives me wiggle room to do what I want.

4) Well, sure it'll happen another way somewhere else, but you're not there are ya? All of humanity is doomed to die, all life is pointless, but should we just lay down and die then?

5) My 1 or your 1? Personally I don't think Paradox exist, just because our puny human minds can't comprehend something doesn't mean it can't happen. I don't think that the universe cares about paradox.

As for killing every grandfather ever, no it's not possible. I -really- hate the word infinity. The word itself inheirantly limits something unlimitable. It's big, really big. So big you can't even comprehend it! Think of the hugest thing you can think of. That's nothing! Absolutely NOTHING to the supreme BIGNESS of infinity.

A person't past is immutable. You can erase the effects of that person's past, erase the memory, make it like it never happened, but it did. Ultimately, as cruel as it sounds, each individual is the most important person to themselves. For all I know, you all could be an illusion from bad cheese!

I DO appreciate all your questions though, these are things that never occured to me, and the type of things that my characters really should ask about.

 

[Steerpike]

I think any "time travel" scenario is going to have potential problems. Here is one way to look at it that may or may minimize some of those problems.

I'd eliminate infinite timelines. As noted above, I think things become much less meaningful when every possibility exists somewhere. Instead, I'd say the default is that there is a single timeline to begin with. As time moves forward, potential timeslines exist in the penumbra of the main timeline, and the potential timelines represent the possible directions the main timeline can take. But as soon as the "choice" is made in the main timeline, these potential timelines all collapse into the main, so the one timeline is the only one that has any reality. At any given time, the main timeline is swirling with potential timelines representing alternatives, but only one combination of those potentials is realized and becomes the 'real' timeline.

When the time traveler goes back, however, the universe has to resolve the inherent paradox of her presence. This can only be done by a second timeline becoming "real," the second timeline now running parallel to the first but differing in that the time traveler is there, and differing in all of her actions, the consequences of her actions, etc.

The formation of a new "real" timeline would only occur when the universe is faced with a necessary paradox. So if a time traveler went back 600 million years and impacted nothing, or nothing in a way that causes paradox, then the effect is that maybe some different potential timelines become "real" than would have happened without him, but unless and until he does something that would cause a paradoxical effect in his own timeline the potential timelines collapse around the main one as always.

I'm sure there are problems with it, and I'll probably think of some of them after I post this. But I think it gives you a little more meaning if there are only two timelines, rather than an infinite number, and it also now gives the time cops something to do. Of course, the problem is, by merely doing something like pursuing the time traveler and trying to stop her, the time cops are probably going to do things that lead to paradoxes, and now you have a third timeline. But maybe the idea is that even if a second timeline is formed, if the time cops can "fix" everything as best they can, the two "real" timelines will at some point reach a state where they'll merge back into one, so the time cops role could be to mitigate the harm of the traveler, as well as the harm they, the cops, cause.

Hmmmmm. Well, I'll throw this out there and then muse it over more as well.

 

[Sheilawisz]

I believe that in a travel to the past you would not travel to another timeline or another dimension: You would actually travel to a different world in some other universe completely separated from your own =) For me, the past does not exist so you cannot travel to a place that does not exist at all... travelling to the future is more interesting!!

 

[Steerpike]

I like future travel or travel to the past, if it is well done. I just don't like the infinite timeline idea because my reaction to stories that include it is "OK, so what?"

Here I am following the protagonist in one of an infinite number of timelines. Maybe he lives, maybe he dies. Maybe he achieves his goals, maybe he doesn't. Who cares? For every thing that goes wrong for him in the timeline I'm reading, there are an infinite number where they go right. Why is the author arbitrarily following this timeline instead of another one? Who cares what happens to the characters - everything that can possibly happen to them is happening in in an infinite number of timelines. Everything in the story becomes an arbitrary choice of the author to follow one timeline over another, so the story is meaningless. I think if you're going to have travel into the past, you have to maintain a sense that what the characters are doing actually matters.

 

[BeigePalladin]

@BeigePalladin: Yep, pretty much. The infinite nature of the timelines would also mean that the time police HAD to exist, regardless of how futile it would be. Mostly though, you wouldn't think about it too much, you don't mess with the time police, they're scary. Also, not everybody that time travels knows the truth about time travel, so they don't know about skipping steps or what not.

but...but... no. Nothing justifies willful stupidity of every potential "timeline" - It'd be fine if the time police only existed in limited time lines, but saying they must exist when they'd hae to know the truth about time travel means they must recruit people who either willfully reject the laws of their reality (whilst trying to enforce arbitary laws upon other people in the most painfully hypocritical manner), or who are too dense to understand - at which point it would be impossible for them to be scary without an authorical asspull

1) This is not news to me, I explained why paradox doesn't really matter. Stoping people that want to change the past is one of the Time Police's duties.

no, you said it was impossible to cause a paradox. you also said everything ever will happen anyway, so the police may have that duty but it will never be enforced. thus furthering the fact their a pointless group that seems to hae been thrown in there as an ass pull (also, if histoy is immutable and unchanagble, they'd become even more pointless since they could never do anything, not simply fail most of the time)

A person't past is immutable. You can erase the effects of that person's past, erase the memory, make it like it never happened, but it did. Ultimately, as cruel as it sounds, each individual is the most important person to themselves. For all I know, you all could be an illusion from bad cheese!

Not to sound rude, but did you read this before putting it down? So eeryone's past is immutible but you can change everyones past but yourself. Pick one of the two man, the two contradict one another and you really can't have them together due to that fact. If someone can change someone else's past because they consider that someone else less important, the the end result of that is the past can be changed. If the past cannot be changed, then you'd never be able to change someone else's past.

3) Nope, no it is not time travel. It's close enough though! Technically it's not traveling to alternate realities, but the differences between the two would require a post-technological-singularity mind to have any hope of understanding. Mainly that just gives me wiggle room to do what I want.

nope. if the other unierse will exist regardless, but with differences from your own predetermined at creation (due to the unable to change history), then it is merely traveling to a different dimension.
It may be different to you, but the way you describe it means it comes across exactly as that to everyone else due to our lack of the ability to read your mind, and as such it comes across as you wanting to write a story with time travel but without the time travel.

4) Well, sure it'll happen another way somewhere else, but you're not there are ya? All of humanity is doomed to die, all life is pointless, but should we just lay down and die then?

Becuase outside of litreature we hae this thing called uncertainty, where we don't know if there are infinate unierses and whathave you, so we have hope.
Drop that and, well, welcome to nihhilism - because if it's confirmed that everything that can happen will happen and wether your universe if f***** or not before you where ever born, the life viw that everything is pointless and we should just stop will become very far spread.. And yes, people who actually have that life life view that everything is pointless and unchangeable, or that nothing they do will matter are very well documented to either kill themselves or becomes mass murderers.

Especially since you pointed out veryone is the most important person in the world to themselves.

lastly, something to bring up about paradox:

A paradox is when something that cannot happen has happened - and, as much as I hate to shatter your delusion, a person cannot be born if their decendants where killed before the conception process, thus making it impossible. If someone kills their own grandfather, then they have either changed history and thus they may not be born (someone identical in all respects but with a different ancestor could be born, but they would not be the same person, thus history would have changed) or created a paradox; now, we have no clue as to what the outcome of a paradox would be - nor anyway of determining it - but since humanity invented the freaking term as a theoretical point, the size of the unierse matters diddly squat to that.

Overview:

I think you have too many rules, and they're causing this to seem painfully stupid and overly conoluted - as evidenced by the number of hypocracies. You yourself say it's impossible to understand, yet your putting in solid rules - which means that it should be understandable.

Because the rules presented here are storykillers that will make people not want to read it, and you yourself seem to be rallying against them with later rules.

 

[Queshire]

Maaaaan~~~ am I really explaining it that bad? Le~sigh...

I did summarize it to the essentials in my second post.

Admittedly, the Time Police are something of a last minute addition to stop people from abusing time travel in a world where paradox and predetermination doesn't exist.

Time travel is an element of my stories, it's not the biggest or most important one, but it's there.

Now, I don't plan on doing it, trying to find hope and reason in an infinite number of timelines could be the main point of a story. Ultimately though, humanity's limited, even if there's an infinite number of timelines, a human will only experience a few of them, and what they do is bloody well matters to them!

I... don't really get what you're trying to say in that first part BeigePalladin.... The time police exist, because there's an infinite number of timelines, they HAVE to exist, and they have the ability to travel to other timelines. I see nothing hypocritcal about them, they aren't trying to make the timelines go a different way, they just want to stop people able to time travel from wantonly scwrewing with people that don't. I mean, it's one thing if in a certain timeline Hitler trips down the stairs and dies then if a time traveller jumps to that time line and shoots him. Even without historically significant events like that, is there anything wrong with trying to stop a time traveller from going back and randomly mudering someone? Futile maybe, but they have to do SOMETHING.

Ngggh............... Yes, technically everything that could happen will happen in one of the alternate realities, but again, Humanity is limited. They aren't trying to enforce it in every timeline, just the timelines that are their particular jurisdiction.

What matters is the individual. What happened to YOU happened. Going back in time and changing something won't cause yourself to automatically update to reflect it. In the same vein, going back and changing someone's past isn't changing their past, they won't automatically update to reflect the changes either. It's simply changing that particular version of the character's future!

Pretty much yeah, it's close enough to time travel to be used as time travel without the problem of time travel. If you could go see a historical moment, say the moon landing, and it happens exactly as it did according to history, does it matter if it's actual time travel or traveling to alternate realities?

The thing about alternate realities is that they're alternate. From the character's vantage, there's still uncertainty and hope. The characters still have to work for their own personal happiness.
I swear, I have to keep repeating this. WHAT HAPPENED, HAPPENED. THE FUTURE IS NOT DETERMINED UNTIL IT HAPPENS. Your universe is not predetemined one way or another at any point. Infinitiy simply means that invaribly the dice WILL fall the other way. Just because some other universe is the "good" universe doesn't mean yours is the "bad" one. You could do things just the same as that universe, or even better! It doesn't matter if two universes are completeley identical in every way, they can still be alternatives. INFINITY IS JUST THAT BIG.

As for paradoxes, if it happened then obviously it's impossible. Just because we can't understand HOW does not matter. Going back in history to kill your grandfather doesn't change your past, it simply changes that timeline's future.