Time travel paradoxes in movies: Do you care?

Cafe Society
21

Two thoughts on this – how does Steven Hawking know we aren’t being invaded by time-tourists from the future? We would suppose they’d take some sort of Prime Directive Oath (though of course, you may argue, a visitor would altar the past [now] by the mere act of visiting it). However, what about the future-person’s visit actually being part of our present, and making sense? In a vague way, I’m thinking of the movie 12 Monkeys, where a voice mail message is tortureously pieced together because they think it’s relevent to the disease – and we discover later that it doesn’t, it was just their preconceived notion that EVERYTHING that happened around that time had to do with the advent of the diesease. (I wonder if I’m remembering the plot accurately at all, lol).

What bugs me is just the type scene Ender describes: turning around and seeing himself 10 years older, handing him something. For time travel to work for me, people can’t exist in duplicate. For time travel to be “true” you’re either here, and now, or in the past. You can’t catch up with your other self, there’s only one you, right? So the end of Back to the Future bothers me – Marty comes forward in time to see himself stand in the parking lot, jump into the Delorian and rocket into the future. Bah. I can better handle the paradox in Terminator. I know it’s not possible, but for the duration of the movie, I “believe” it.

Another example of the thing that simply is (like the Beatles music) is in the maudlin Somewhere in Time with Christopher Reeve and Jane Seymour. Old lady appears to Chris, hands him a watch and says, “Come back to me.” Plot ensues, and Chris goes back to the early 1900s, meets Jane and falls in love. When he pulls a 1979 penny from his trouser pocket, he is propelled back to the future, accidentally leaving his watch behind. Jane hangs out for 70 years, shows up and gives him his watch, which he’s never seen before… so where’d the watch come from?

22

You think that, but really Future Ender invented the machine and thought about visiting you. Then he said “Screw that” and is in ancient Babylonia impressing concubines with his Zippo lighter and handheld Battleship game.

23

They bother me to an extent because they are at this point so cliched. I liked that tribble episode of DS9 where Sisco is giving a report to the time cops and he says something like “we know we didn’t change anything because of we did we’d be the first ones to notice it when we got back” and one of the time cops turns to the other one and groans “why do they always say that?”

Actually I think the rotten way the various Trek series have handled time travel episodes might be what soured me and other people on the concept. Particularly annoying ones in the recent past on Voyager were the “Old Kes goes back in time to destroy Voyager but younger Kes convinces her not to by taping a message six years ago.” Well, if Kes taped the message six years ago, how come the first time Old Kess showed up Janeway et. al. were surprised by it? Why, when Kes was leaving Voyager, did janeway not upload a copy of the message to her? Why, if Kes recorded the message, would Old Kes bother coming back at all, since she already knew that she would not follow through on her plan? Also the “Voyager gets split into several time regions then join back together but no one remembers anything about meeting each other from different time periods” episode. And why exactly would they not remember it? Dreadful.

24

Well, I can prove that if time travel is possible, it is nevertheless impossible to change the past.

Imagine a universe where one can travel through time and change the past. Everyone who gets their hands on a time machine goes back, and changes the past over and over again. The timelines are in constant flux, until one specific change happens. Someone goes back and changes the past so that no one ever builds a time machine. At that point, the timeline is fixed permanently. And that must be the timeline we live in…the one where time machines are never invented.

The best paradox, “where did the time machine come from” box is David Gerrold’s “The Man who Folded Himself”. Kid gets a box from his deceased “uncle” containing a timebelt and a book of instructions. But where does the timebelt really come from? Let’s just say that the kid becomes very familiar with himself. He constantly goes back in time to give himself advice, or just to keep himself company.

The trouble is, once you have a time machine, then cause and effect can be reversed. And if we let that happen, then all kinds of things become possible…time machines that are never built but just appear, people and things that cause their own creation, etc.

If time machines are possible, then how could you say when a time machine was invented. All you have to do is go back in time with the blueprints for a time machine and hand it to your younger self. Except he doesn’t even need to build the time machine since you can bring him back one from the future. So, if time travel is possible then where are they?

25

Information from nowhere Time Paradox:

(aka the Beatles problem)

So you build a time machine and take John Lennon a record of Imagine, he rerecords it, and never writes the song. Where did it come from?

Simple, John Lennon wrote it.

That is, in Universe A, John Lennon-A wrote the song. You took it back in time. As soon as you arrived, the universe branches into 2 divisions. In Universe A, you haven’t traveled through time. The present of Universe B has the consequences of what you’re about to do. When you go back in the Time Machine, you will land in present-B. You can’t ever get back to present-A, although you can create a present-c that is identical by going back and stopping yourself from building the time machine.

Anyway, Lennon-A wrote the song and both he and Lennon-B got rich off it. The song got written.

Of course, if you don’t believe that the universe can split then history can’t be changed by time travel… that is the zipper theory, that history fits together like a zipper. You will get hit by a truck before you can give John the song because he didn’e get the song from a time traveler and he never will or can.

The third possibility is that time travel is not possible; however, i have never heard an argument for the third possibility that the other two couldn’t also explain.

–John

26

SO lets take this beatles thing through to it’s ultimate conclusion:

Human in the far future theorises how the Universe began. He/she realises that it required a mechanism to set it into motion which did not exist in the Beginning. He/she realises that they must travel back in time (using the new fangled time machine that they were working on in their spare time) with a Cosmic Initiator and set the Universe in motion. He/she does this. The Universe exists. Thus the Creator/God is a Human Being.

Now how’s that for arrogance?

:slight_smile:

28

I mind! Yes, I mind!

A really simple example, also ala Back To The Future. It’s 1955 and Marty is playing Johnny B. Goode on his guitar, and one of his backups is “Marvin Berry”. Marvin goes to the phone and calls his cousin, Chuck Berry, to tell him about this awesome song, the implication being that CB didn’t really write the song, it was a “gift from the future”. Where does that leave the actual creation of the song, with God? I can see god now, doing that one-leg forward jump-bounce as he strums a white guitar and gets his beard caught in the strings. Marty only knew the song because CB wrote it, but CB only wrote it because Marty played it for him? Aaak, I can’t get my head around that.

I’m not Mr. Spock. You tell me I have to start out agreeing that someone can live forever drinking other people’s blood, well ok, that’s the premise and off we go. If they suddenly die because that blood is infected with AIDS? well, not so much. The whole point is that they’re undead immortal beings beyond human disease, you, writer, made that the central idea. Finding a “twist” that revokes the premise I’ve been forced to labor under all along is cheating. Big thumbs down to T2 for that one.

I did forgive Back To The Future, since the Chuck Berry thing was so secondary to the plot, just a little decoration that would have been better left off. Not quite as generous with BTTF2, when the danger is meeting up with one’s own self. How many unique consciousnesses can one person have???

29

This has been explained in various SF short stories (Anthony Boucher’s “The Barrier,” for instance).

Dealing with time paradoxes are a big part of the fun of time travel stories. “The Men Who Murdered Muhammad” by Alfred Bester also has an answer to the question.

As for me, it all depends on what the paradox is, and how it’s dealt with.

30

Does a zombie thread re-opened by someone who gets banned in less than a month count as a time paradox?

I don’t care unless the movie is about the time paradox itself and then it doesn’t make sense. As an example future Bill and Ted helping out present Bill and Ted when we know they should have been too stoned and stupid to remember to go back and do that.

31

Well after all, God gave rock and roll to you. :smiley:

32

A couple of years ago I had an idea for a story with an opening scene similar to this in which some researchers make a machine that can supposedly receive messages from the future but when they switch it on for the first time they only hear jumbled white noise. Turns out that the machine works but is overwhelmed by messages from countless amateurs and school classes from the future messaging the creators of first machine.

Now I see this is a very old thread so I wonder if I read this post years ago and subconsciously absorbed it into my mind. Therefore I wonder where the point of creation was?

33

I was surprised nobody mentioned either of two excellent time-travel movies, Déjà vu and Source Code. Then I noticed the zombie thread predates both movies. :slight_smile:

I wish somone would start a Cafe Society thread, Disbelief suspension: When is it easy? When is it intolerable? I think the answers would vary dramatically.

34

This. I can suspend disbelief in a time-travel gimmick for the length of a movie, as long as it doesn’t blatantly contradict itself in that span. For two hours, I can just be along for the ride.

If it’s a book, it has to be well enough constructed that I can live with it for the time it takes to read the book, which is usually bits and pieces of time scattered over days. The problems with time travel have to be papered over in a more seemingly solid manner, but if the author can do that, I can enjoy the ride.

I can always find the holes later, but if the ride was good, then I’m not bothered by it.

If I were to re-watch BTTF, for instance, the part I’d have the most trouble with (for me, the bit with the fading photo is kinda charming in its absurdity) is when Marty wakes up back in 1985, stumbles into the kitchen, realizes it’s quite different, and says to his siblings, “Hey. What the hell is this?” and they look at him quizzically and one of them says, “Breakfast.”

OK, so he’s just jumped from his original 1985, back to 1955, where he’s done some things that resulted in a new, improved life for him and his family in 1985 and the years preceding. And he’s jumped to this new, improved 1985 directly from 1955, so he doesn’t remember any of it. He hasn’t lived any of it.

But some alt-Marty, who would have woken up that morning with no idea that anything was different, has lived it. Where is alt-Marty? What’s happened to him? Where have his life experiences and memories gone? They’re not kicking around ur-Marty’s head. They’re just gone. And nobody - parents, siblings, girlfriend - notices that he’s a different Marty than the one they’ve known.

Fortunately, this happens near enough to the end of the movie that it doesn’t really matter. If something as problematic as this happened in the first hour of the movie, I’d never make it through the rest of the movie.

35

I care about paradoxes. I like to see them properly resolved, but examples of really cleverly dealing with such things are rare, and movies in which there are no irregularities are virtually nonexistent.

I’m not really fond of the “where did it come from?” trope, although it doesn’t really annoy me THAT much. An example is the pair of spectacles that McCoy gave Kirk as a birthday present in Star Trek II and that he sells for money in Star Trek IV (“Weren’t those a present from Dr. McCoy?” “And they will be again – that’s the beauty of it!”) (That was a throwaway present from writer Nicholas Meyer, who had given us Time After Time, among other things) Heck, the concept is the entire basis of Heinlein’s All You Zombies. But it’s a cheat, nonetheless.

36

One movie handled it pretty well, I feel. That movie is “Source Code”.

In the movie, the protagonist has had a horrific injury exposing his brain. Mad scientists are able to connect electrodes to his brain and somehow connect them with the recently dead brains of victims of a disaster. The military mad scientists do not know what the protagonist experiences, they only know that he can somehow obtain information from these brains and tell them what he finds out through a crude voice link.

Well, from the protagonist’s perspective, “reading” the brain tissue puts him in a world that is indistinguishable in all respects from reality, set in the recent past before the victims died. He is told that this place is not real, but his direct experience says otherwise.

Eventually, he is able to prevent the disaster from ever happening, having overwritten the mind of a victim of that disaster. He is now free to do what he likes in a parallel world. He makes a phone call to let another character in the movie who is part of the mad science team that “everything is going to be ok”.

This creates a very interesting scenario.

Timeline A1 : Scientists hook up the “source code”. A disaster happens, and using this device, they find out who did it.
Timelines A2-AN : scratch timelines where the protagonist failed to stop the disaster
Timeline B1 : In this timeline, the protagonist prevents the first disaster from happening. The scientists must wait to even use the source code.
Timelines B2-BN : scratch timelines where the protagonist failed to stop the disaster
Timeline C1 : …

This continues until a timeline somewhere exists where :

Timeline Z1 : Scientists hook up the “source code”. Disasters are mysteriously halted by lone individuals who seemingly know about them in advance all over the world. The scientists fail to get a suitable disaster that they can test out their “source code” machine and must wait years. Before turning the machine on, these disasters happened every few days.

They turn the machine off as an experiment, and disasters become common as a result until they turn it on again.

TLDR : the use of the machine “source code” creates a timeline somewhere in the multiverse where this machine mysteriously prevents the very disasters it is designed to investigate. No one can explain how it does it, yet the evidence (a statistically significant lack of disasters that happens when the machine is turned on) is compelling.

37

In that case, the song was still written by Chuck Berry. Time travel in that franchise allows one to easily rewrite history, while the time traveler retains memories of the original timeline. At the beginning of the movie, Marty McFly did not exist in the 1950s, and Chuck Berry wrote Johnny B. Goode without ever receiving a phone call from his cousin, Marvin.

After Marty travels back in time, he’s essentially rewritten everyone in the timeline, including Chuck Berry, who now wrote Johnny B. Goode after getting a call from his cousin. The song was written by Chuck Berry Prime, who ceased to exist after Marty’s trip, and was replaced by a Chuck Berry who heard the song over the phone.

It’s also worth pointing out that, even in the new time line, Chuck was listening to a live concert over a public telephone using a 1950’s era landline, on what was presumably a long distance phone call that was started in the middle of the song. It unlikely he heard much of anything of the actual song, and still would have had to recreate most of it himself. Which, of course, ends up being pretty much exactly the same song, because he was supposed to be the guy who wrote it in the first place.

My favorite example of this sort of story is from Tim Powers The Anubis Gates. A professor specialized in a particular Victorian poet finds himself stranded in 19th century London. He’s surprised to find that he’s landed there on the exact date that the poet wrote his first and most famous poem, in a London coffee house. He goes there to meet the man, but finds he’s arrived early, so settles in to wait. While waiting, he conceives of a plan to prove his credentials as a time traveler - he writes out the text of the poem from memory, and plans to show it to the poet immediately after he’s finished composing the original, before he could possibly show it to anyone. But the poet never shows up, and the professor leaves, puzzled as to how he could have been wrong about such a simple and well established fact about his favorite poet.

What he comes to realize, of course, is that he’s the poet he’s been studying all his life, and he just “composed” the poem in that coffee shop at that particular date. At the end of the novel, he stays in Victorian England, earning a good living by carefully writing out “his” poems from memory, and publishing them at the proper date and in the proper magazine.

38

One of two things happened. If we assume that Marty’s original time travel created a branch (parallel) timeline, starting at the point he arrived in the past, he returns to the future of that new timeline. Lone Pines Mall, broken ledge in the clock tower (it wasn’t broken in the opening of the movie), sci-fi author dad, Toyota in the garage, Doc alive with bullet proof vest.

Now alt-marty, poor boy, who travels from Lone Pines mall, ends up in the original timeline, perhaps because there is already a Marty in alt-Marty’s timeline (temporal conservation of mass, maybe?). Since he has a Toyota, he probably knows how to drive, so he doesn’t kill the twin pines. Also, since maybe he’s a bit smarter that real-Marty, he doesn’t make any changes in the past.

When he returns to the future, the only timeline “open” to him is the original timeline. Loser family, no truck, unmarred clock tower, and dead Doc (no bullet proof vest).

Neither one of the Martys knows anything about the timeline they are stuck in. But alt-Marty doesn’t even have anyone to talk about it with. No one will ever believe his time travel (even with the car as “proof”), without doc to make it work.

The other thing that could have happened is that when original Marty made the new timeline, the old one is gone forever. So if alt-Marty goes back, he either creates a brand new timeline (erasing the one at the end of the movie, and the sequels) or he goes nowhere. Poof!

39

I remember an episode of “Quantum Leap” where Sam Beckett gives Buddy Holly a hand with the lyrics to “Peggy Sue”, add in “Johnny Be Good” and “Imagine”, maybe all our big hits were from time travelers.

Anybody want to talk about “Time Cop”, a not-half-bad VanDamme movie. He goes back in time, stops the bad guy, returns to the present and his now-undeceased wife is waiting for him. Except if the bad guy disappeared years ago, why did he even go to the past? I always thought it would be cool for him to have come back, go home and see the Mrs. on the front porch greeting her husband, the guy who never made this trip. Imagine discovering that you’re an “artifact” from a timeline that no longer exists.

40

Maybe so. :slight_smile: I remember the “Quantum Leap” episode in which Sam leapt into his younger self in 1969 and frightens his sister when he sings “Imagine” to her. She wonders why she never heard it before and Sam explains to her that’s because it hasn’t been written yet.

41

Timeline. The book and AFAIK the movie as well.

This has always bugged me and I’ve mentioned it here before.

In Timeline we’re told it’s not really time travel but instead they travel to another dimension where the past is happening now.

All this is fine once you buy into the idea, however the professor writes on something and it is found by the people not in the future but in another dimension? How is this possible? This event is the catalyst for the whole adventure.

Yes a professor from another dimension could have traveled to our dimension and left the item in the past but nothing like this is ever mentioned.

Always annoyed me that Crichton made such a fundamental error.