# Time-travel fiction with rules that make sense **URL:** \ **Category:** Cafe Society\ **Created:** [October 1, 2008, 8:07pm UTC](https://boards.straightdope.com/t/time-travel-fiction-with-rules-that-make-sense/466062 "2008-10-01T20:07:57Z")\ **Posts on this page:** 20\ **Page:** 3
**Author:** ![Zsofia](https://avatars.discourse-cdn.com/v4/letter/z/7bcc69/32.png) [@Zsofia](https://boards.straightdope.com/u/Zsofia)\ **Post date:** [October 2, 2008, 3:18am UTC](https://boards.straightdope.com/t/time-travel-fiction-with-rules-that-make-sense/466062/41 "2008-10-02T03:18:44Z")
> [@Grumman](#): > > Why not? Do the laws of the universe apply equally in all cases except where m=spaceship? > This is a thread about time-travel fiction with rules that make sense. If the story revolves around arbitrary and ill-defined rules, then it isn’t a piece of fiction with rules that make sense. They apply just fine when you’re going to take your spaceship and go fucking around with the continuum which Is Not Allowed. If you start out with a self-preserving time continuum why would you think it wouldn’t know what you were up to, because obviously you didn’t do it. Your time now is still part of it, you know. You can’t just go “Look, over there!” and put your spaceship in your pocket. Whatever you want to do you are not going to be allowed to do it if it’s going to affect anything. That means that if you were going to go back and change something, you won’t be allowed to go back. Because you didn’t, see. This isn’t a world in which you get alternate universes splitting off (or if it is we don’t know about it), this is a world where the continuum, intelligently or not, protects itself. It isn’t an ill-defined rule, IMHO - any time travel rule is “arbitrary”. ETA - is the idea of splitting universes any less arbitrary? People talk about that in time travel threads like it’s a scientific law or something. It’s no less arbitrary to posit a self-protecting timeline, IMHO - I mean, starting out with infinite universes is just as arbitrary. ---
**Author:** ![Gadarene](https://avatars.discourse-cdn.com/v4/letter/g/e47c2d/32.png) [@Gadarene](https://boards.straightdope.com/u/Gadarene)\ **Post date:** [October 2, 2008, 3:23am UTC](https://boards.straightdope.com/t/time-travel-fiction-with-rules-that-make-sense/466062/42 "2008-10-02T03:23:18Z")
I agree with **Zsofia**. ---
**Author:** ![Bosstone](https://avatars.discourse-cdn.com/v4/letter/b/22d042/32.png) [@Bosstone](https://boards.straightdope.com/u/Bosstone)\ **Post date:** [October 2, 2008, 3:38am UTC](https://boards.straightdope.com/t/time-travel-fiction-with-rules-that-make-sense/466062/43 "2008-10-02T03:38:06Z")
> [@Balance](#): > > The shakiest thing, from a logical point of view, is the barrier event in the future. There’s a point beyond which the future is too unstable for current time travelers to travel into, because too many events beyond that point depend on a single, crucial decision. (This has just been resolved in the print comics, but is still a ways off in the online version.) It _just_ got mentioned in the online comic, in fact. Damn, but I like Aaron William’s stuff, it’s nearly as good as the Foglios’. Speaking of, _Girl Genius_ has alluded to time travel, in that the protagonist has briefly popped in from the future, but nothing’s come of it in the primary timeline yet. Interested to see where that goes. ---
**Author:** ![Bootis](https://avatars.discourse-cdn.com/v4/letter/b/e8c25b/32.png) [@Bootis](https://boards.straightdope.com/u/Bootis)\ **Post date:** [October 2, 2008, 4:47am UTC](https://boards.straightdope.com/t/time-travel-fiction-with-rules-that-make-sense/466062/44 "2008-10-02T04:47:45Z")
> [@KneadToKnow](#): > > I concur fully. Rowling really out-did herself with the Time Turner. And I appreciated from a storytelling standpoint why she had to do what she did to them in _Order of the Phoenix_. The only problem I had with those time turners, is that they are maybe the most dangerous magical items in their world, (Imagine what Voldemort could do with one!) They are not something to be taken or used lightly. So there’s no way Dumbledore would ever give one to Hermione, just so she can take a couple extra classes, because she wants to take lots of classes. That’s just inexcusably reckless. ---
**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\ **Post date:** [October 2, 2008, 4:59am UTC](https://boards.straightdope.com/t/time-travel-fiction-with-rules-that-make-sense/466062/45 "2008-10-02T04:59:09Z")
For all we know, Dumbledore had put an undetectable and unbreakable hex on it to limit it to Hermione’s use, within certain parameters (not going back to before she enrolled at Hogwarts, for instance). It doesn’t really bother me. Dumbledore is many things, but he’s not typically reckless. **Askance** , IIRC Henry in _The Time Traveler’s Wife_ could travel in time both to before his own birth (he talks about seeing his pregnant mother in the streets of Chicago), and after his own death (as when he visits Claire when she’s an old lady in the beach house). Those seem to be the earliest and latest time trips he ever took. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [October 2, 2008, 12:06pm UTC](https://boards.straightdope.com/t/time-travel-fiction-with-rules-that-make-sense/466062/46 "2008-10-02T12:06:39Z")
> [@](#): > > Of course you can eliminate the Grandfather Paradox in the completely opposite way by making nothing you do in the past have any consequence at all. You simply create a new timeline from which you didn’t originate. Yeah, but then you have that problem with branching timelines and alternate realities, which always make me uncomfortable – it doesn’t eliminate the Grandfather Paradox, it sidesteps it, leaving other problems in its wake. And people tend to get sloppy and have people crossing between these alternate realities, which brings the paradox right ack again. ---
**Author:** ![KneadToKnow](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kneadtoknow/32/3999_2.png) [@KneadToKnow](https://boards.straightdope.com/u/KneadToKnow)\ **Post date:** [October 2, 2008, 1:01pm UTC](https://boards.straightdope.com/t/time-travel-fiction-with-rules-that-make-sense/466062/47 "2008-10-02T13:01:21Z")
Outside of Time Turners, I like the “cannot make any lasting changes” way of dealing with the past because it reinforces the notion that time is like a river. Yeah, you can swim upstream and muck about and splash around and cause lots of local disturbances, but the water is going to keep flowing and it’s all going to wind up the same place.\* - Which the special effects idiots from _Rise of the Silver Surfer_ would do well to note if they’re ever given the chance to go back in time and correct the Thames River scene. ---
**Author:** ![drillrod](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@drillrod](https://boards.straightdope.com/u/drillrod)\ **Post date:** [October 2, 2008, 1:40pm UTC](https://boards.straightdope.com/t/time-travel-fiction-with-rules-that-make-sense/466062/48 "2008-10-02T13:40:33Z")
Dean Koontz’ **Lightning** is actually a pretty good book featuring time travel. Well, the story is still a Dean Koontz story, but the time travel aspect is handled pretty well, with logical and consistent rules. ---
**Author:** ![Fly\_Pusher](https://avatars.discourse-cdn.com/v4/letter/f/c5a1d2/32.png) [@Fly\_Pusher](https://boards.straightdope.com/u/Fly_Pusher)\ **Post date:** [October 2, 2008, 1:48pm UTC](https://boards.straightdope.com/t/time-travel-fiction-with-rules-that-make-sense/466062/49 "2008-10-02T13:48:51Z")
My favorite solution to the Grandfather paradox is a variant of the weak anthropic principle: any universe were the grandfather paradox occurs is completely destroyed, thus any universe that we can exist in never had any grandfather paradox. You can’t go back and kill your grandfather because if you did, your entire universe would never have existed. I think that ups the ante :). ---
**Author:** ![Wargamer](https://avatars.discourse-cdn.com/v4/letter/w/df705f/32.png) [@Wargamer](https://boards.straightdope.com/u/Wargamer)\ **Post date:** [October 2, 2008, 2:13pm UTC](https://boards.straightdope.com/t/time-travel-fiction-with-rules-that-make-sense/466062/50 "2008-10-02T14:13:49Z")
> [@WarmNPrickly](#): > > Of course you can eliminate the Grandfather Paradox in the completely opposite way by making nothing you do in the past have any consequence at all. You simply create a new timeline from which you didn’t originate. “What paradox?”, said Granddad, as he stepped out of the time machine with a shotgun. ---
**Author:** ![Baldwin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/baldwin/32/7264_2.png) [@Baldwin](https://boards.straightdope.com/u/Baldwin)\ **Post date:** [October 2, 2008, 2:40pm UTC](https://boards.straightdope.com/t/time-travel-fiction-with-rules-that-make-sense/466062/51 "2008-10-02T14:40:45Z")
> [@Dogzilla](#): > > I have to disagree because Terminator was the first time-travel movie that presented a huge plot hole/paradox to me that bugs the crap out of me and killed the movies for me forever. > > Let me 'splain. > > When Reese finds Sarah Connor and starts explaining to her that her future son sent him back from the future to find her and protect her, he tells her that her son’s name is John Connor (eventually). > > So, at the end of the movie, you see that Sarah has conceived John and she’s making a little video diary for him as she’s driving in Mexico. Obviously, she names her kid John because in T2, of course, her son is John. > > But she only named him that because Reese told her that was her son’s name. Couldn’t she have averted the next three awful movies by simply naming her kid Billy or something? Who really named John? _Nobody_. Sarah played into the “prophecy” and made it self-fulfilling by making sure her kid was named the same thing as the name Kyle told her. > > I’ve gone around and around with this, but AFAICT… nobody named John. That’s not really a paradox; it’s one of them causality loops. Information (or artifacts) from Nowhere. Perhaps the best fictional treatment of this problem is the short story – okay, can’t recall the title right now, but I’ll find it when I go home – that involves a knife of unknown translucent blue metal, which is brought from the future, housed in a museum, then centuries later, after a devastating war, it is taken from the ruins of the museum and brought into the past, where it’s housed in the museum. . . In the deleted scenes on the _Terminator_ DVD extras, there’s some good dialogue between Reese and Sarah that basically lays out the two main sf philosophies of time travel – he argues that they can’t prevent Judgement Day, they can only ensure that John Conner is born and survives; she believes they can stop Judgement Day from happening. The only way it ever made sense to me was if you immediately create a separate timeline when you go into the past, in which case nothing you do will alter the history of your original timeline. This idea was explored entertainingly in a story by (if I recall) Stephen Baxter, in which it’s possible to create a sort of pipe, one end of which stays in your own timeline, the other of which extends into the past, and stays with the alternate timeline you create. The application of this is that the future people treat the past (if I recall, the 18th century) as a Third World country; they trade future trinkets for the privilege of looting the untapped natural resources of an 18th century Earth. They literally run an oil pipeline from the past to the future. ---
**Author:** ![Quercus](https://avatars.discourse-cdn.com/v4/letter/q/7ab992/32.png) [@Quercus](https://boards.straightdope.com/u/Quercus)\ **Post date:** [October 2, 2008, 2:48pm UTC](https://boards.straightdope.com/t/time-travel-fiction-with-rules-that-make-sense/466062/52 "2008-10-02T14:48:53Z")
> [@Bootis](#): > > The only problem I had with those time turners, is that they are maybe the most dangerous magical items in their world, (Imagine what Voldemort could do with one!) > They are not something to be taken or used lightly. So there’s no way Dumbledore would ever give one to Hermione, just so she can take a couple extra classes, because she wants to take lots of classes. That’s just inexcusably reckless. Yeah, is there a name for that? When a fantasy/science fiction writer has a powerful magic/advanced technological doohickey in one part of the story, then needs to come up with reasons why it won’t solve all the problems in the rest of the story? (Like vitaserum – why is anyone wrongfully imprisoned when a swig of vitaserum would provide pretty absolute proof of innocence?) ---
**Author:** ![OtakuLoki](https://avatars.discourse-cdn.com/v4/letter/o/ac8455/32.png) [@OtakuLoki](https://boards.straightdope.com/u/OtakuLoki)\ **Post date:** [October 2, 2008, 2:51pm UTC](https://boards.straightdope.com/t/time-travel-fiction-with-rules-that-make-sense/466062/53 "2008-10-02T14:51:55Z")
I really think that Larry Niven’s _The Flight of the Horse_’s rules make sense. Larry Niven wrote the story after deciding that time travel had to be a fantasy. So his protagonists think that they’re living in a rational, scientific universe. And end up going back into the past to kidnap an _unicorn_! Or later bringing back Moby Dick. > [@Elendil\_s\_Heir](#): > > Audrey Niffenegger’s novel _The Time Traveler’s Wife_ features a man who > > inadvertently travels through time over and over again, almost as if he were having seizures. He can’t take anything with him, can’t control when or where he goes, and finds that time passes at different rates for him and for those back in his “present.” When he is in the past, he apparently cannot make lasting changes; the past seems set in stone. [spoiler]The implication of that story, as well, is that _the future_ is set in stone, too. What will happen, will happen. For example, all of the post-mortem visits by Henry with Alba are set in his past, even when they remain part of Alba’s future. Just think about all the little things that could happen to change where people are on a given day at a given time, and you’ll see that the only way that Henry’s past becomes immutable is if every else’s future is as well. And since Alba’s time travel seems to work the same way - that means that Henry’s past and future were immutable as well. Now, one may argue whether it’s predestination, or free will, or knowledge in one act. But it does seem as though Niffenegger’s time line is rigid in all directions.[/spoiler] ---
**Author:** ![msmith537](https://avatars.discourse-cdn.com/v4/letter/m/d9b06d/32.png) [@msmith537](https://boards.straightdope.com/u/msmith537)\ **Post date:** [October 2, 2008, 2:59pm UTC](https://boards.straightdope.com/t/time-travel-fiction-with-rules-that-make-sense/466062/54 "2008-10-02T14:59:17Z")
> [@Dogzilla](#): > > But she only named him that because Reese told her that was her son’s name. Couldn’t she have averted the next three awful movies by simply naming her kid Billy or something? Who really named John? _Nobody_. Sarah played into the “prophecy” and made it self-fulfilling by making sure her kid was named the same thing as the name Kyle told her. No because then it would have turned out she was the wrong Sarah Conner. Some other Sarah Conner who didn’t happen to be one of the first three in the phone book would have been the mother of THE John Conner. The problem with The Terminator is not Kyle Reece going back in time and becoming John Conner’s father. That is internally consistent and doesn’t create any paradox or anything. The problem with The Terminator is that pretty much establishes that the who “no fate but what we make” thing is bullshit and the past is (as stated in Twelve Monkeys) basically like a movie that you can’t change but can only see different things each time you view it. In other words, you can sent as many terminators and resistance fighters back in time as you like. But it doesn’t matter because nothing they can do can ultimately alter the events that result in the creation of Skynet and Judgement Day otherwise you would have a paradox. This is actually wrapped up nicely at the end of T-3 when everyone realizes that the mission isn’t to stop the predetermined Judgement Day, it’s to make sure Conner survives it. ---
**Author:** ![Skald\_the\_Rhymer](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Skald\_the\_Rhymer](https://boards.straightdope.com/u/Skald_the_Rhymer)\ **Post date:** [October 2, 2008, 3:46pm UTC](https://boards.straightdope.com/t/time-travel-fiction-with-rules-that-make-sense/466062/55 "2008-10-02T15:46:31Z")
> [@Interrobang](#): > > I think the **Back to the Future** movies establish some consistent rules and play fairly with them, especially considering the series is more comedy than science fiction at its core. Including the bit where Marty Fly is watching the photograph of his family change before his eyes? How DID that work, exactly? :dubious: ---
**Author:** ![flex727](https://avatars.discourse-cdn.com/v4/letter/f/258eb7/32.png) [@flex727](https://boards.straightdope.com/u/flex727)\ **Post date:** [October 2, 2008, 4:07pm UTC](https://boards.straightdope.com/t/time-travel-fiction-with-rules-that-make-sense/466062/56 "2008-10-02T16:07:33Z")
> [@Lemur866](#): > > Also, “The Man Who Folded Himself” by David Gerrold. If you go back in time to advise your past self, pretty soon you’re going to be constantly dealing with older and younger versions of yourself. I loved “The Man Who Folded Himself”, but my favorite time travel book, and most internally consistent is James P. Hogan’s “Thrice Upon a Time”. > [@WarmNPrickly](#): > > Of course you can eliminate the Grandfather Paradox in the completely opposite way by making nothing you do in the past have any consequence at all. You simply create a new timeline from which you didn’t originate. “Thrice Upon a Time” does this and handles it well. ---
**Author:** ![KneadToKnow](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kneadtoknow/32/3999_2.png) [@KneadToKnow](https://boards.straightdope.com/u/KneadToKnow)\ **Post date:** [October 2, 2008, 4:10pm UTC](https://boards.straightdope.com/t/time-travel-fiction-with-rules-that-make-sense/466062/57 "2008-10-02T16:10:56Z")
> [@Quercus](#): > > Yeah, is there a name for that? When a fantasy/science fiction writer has a powerful magic/advanced technological doohickey in one part of the story, then needs to come up with reasons why it won’t solve all the problems in the rest of the story? (Like vitaserum – why is anyone wrongfully imprisoned when a swig of vitaserum would provide pretty absolute proof of innocence?) Nitpick: veritaserum, a portmanteau of _veritas_ (L.: truth) and _serum_. To answer your question: > [@](#): > > Rowling has revealed on her fansite that Veritaserum can be fooled using Occlumency and is not usually accepted in wizard courts. [Cite](http://en.wikipedia.org/wiki/Veritaserum#Veritaserum) ---
**Author:** ![Icerigger](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/icerigger/32/432_2.png) [@Icerigger](https://boards.straightdope.com/u/Icerigger)\ **Post date:** [October 2, 2008, 4:54pm UTC](https://boards.straightdope.com/t/time-travel-fiction-with-rules-that-make-sense/466062/58 "2008-10-02T16:54:32Z")
A silly but neat example. The South Park episode where Cartman freezes himself for 500 years because he did not want to wait for the Nintendo Wii. The future toy market has a device you can use to make crank telephone calls to people in the past. The device has a warning not to actually relay any information to the past because that would alter the time line. Cartman naturally ignores this and contacts the gang back 500 into his past. This has the result of slightly changing Cartman’s time line where aspects of Cartman’s future world change before his eyes but he is completely oblivious to the changes to the time line he meddled with, to him nothing had changed. ---
**Author:** ![c\_goat](https://avatars.discourse-cdn.com/v4/letter/c/f4b2a3/32.png) [@c\_goat](https://boards.straightdope.com/u/c_goat)\ **Post date:** [October 2, 2008, 6:56pm UTC](https://boards.straightdope.com/t/time-travel-fiction-with-rules-that-make-sense/466062/59 "2008-10-02T18:56:15Z")
> [@Lumpy](#): > > I can’t think of the name but there was one time travel story that postulated that you could only travel in time if you were a split-second away from dying, since at that point your further interaction with history would be virtually nill. The discoverer of time travel built a time ship that became a sort of temporal Flying Dutchman, snatching doomed people away at the last possible instant. Sounds like the plot of Freejack (the one with Emilio Estevez and Mick Jagger). They’d snatch people from the past an instant before they died and then sell their bodies to people in the future so the future people could live longer (guess they did a brain transplant or something, I don’t really remember exactly). Though I don’t think there was anything about a ship in that movie, maybe you’ve got two movies mixed or Freejack stole the idea (more likely). If you haven’t seen it, don’t, the movie sucks. Anyway, I personally don’t think it’s possible to have time-travel that makes sense as long as it involves going to the past. Maybe a story that can only travel forward might make sense. Heroes has been killing me lately with this, every problem caused by Peter’s time travel could be fixed with more time travel until they finally get a future that’s not that bad. ---
**Author:** ![Andy\_L](https://avatars.discourse-cdn.com/v4/letter/a/c67d28/32.png) [@Andy\_L](https://boards.straightdope.com/u/Andy_L)\ **Post date:** [October 2, 2008, 11:26pm UTC](https://boards.straightdope.com/t/time-travel-fiction-with-rules-that-make-sense/466062/60 "2008-10-02T23:26:19Z")
> [@c\_goat](#): > > Sounds like the plot of Freejack (the one with Emilio Estevez and Mick Jagger). They’d snatch people from the past an instant before they died and then sell their bodies to people in the future so the future people could live longer (guess they did a brain transplant or something, I don’t really remember exactly). > > Though I don’t think there was anything about a ship in that movie, maybe you’ve got two movies mixed or Freejack stole the idea (more likely). If you haven’t seen it, don’t, the movie sucks. > > Anyway, I personally don’t think it’s possible to have time-travel that makes sense as long as it involves going to the past. Maybe a story that can only travel forward might make sense. Heroes has been killing me lately with this, every problem caused by Peter’s time travel could be fixed with more time travel until they finally get a future that’s not that bad. Freejack is based on a novel - “Immortality Inc” by Sheckley, but the story about catching people at the moment of death sounds more like “Millenium” (by John Varley (expanded from the original short story “Air Raid” and later made into a movie with Kris Kristofferson)), or Fritz Leiber’s “Change War” but neither of those had a flying dutchman like ship [Previous page](https://boards.straightdope.com/t/time-travel-fiction-with-rules-that-make-sense/466062.md?page=2) [Next page](https://boards.straightdope.com/t/time-travel-fiction-with-rules-that-make-sense/466062.md?page=4)