Time Travel in Fiction Rundown


This video is sponsored by the YouTube Red
Sci-Fi Series “Lifeline”. For ages I’ve been wanting to make a video
analyzing time travel in fiction – not the magical or physical mechanisms by which the
time travel is supposedly achieved , but rather, the different ways time travel can influence
causality (and thus the plot) within the universe of each story. Needless to say, there are spoilers ahead! Let’s start with Ender’s Game by Orson Scott
Card – time travel in this book is actually 100% realistic: the characters experience
slower passage of time when they travel close to light speed, allowing just a few days or
months to pass for those traveling while years pass on earth or other planets. It’s traveling forward through time like we
normally do, but at different rates. This kind of time travel doesn’t “change the
past” or allow characters to make different decisions than the ones they already did – it’s
all one consistent historical trajectory. The original Planet of the Apes film is similar,
where astronauts experience extreme time dilation and then crash land on a strange ape-ruled
planet that (major spoiler) turns out to just be earth in the distant future. But what about actual time-travel time travel? Well, I would say there are two big distinguishing
features between different types of time travel in fiction. The first is whether or not the time traveler
is there when history happens the “first time around” – that is, is there a kind of “self-consistency”
where, since time travel takes you to the past, when the past happened the first time,
the time-traveling version of you was always there to begin with? Or does the very act of time traveling to
the past change what happened and force the universe onto a different trajectory of history
from the one you experienced prior to traveling? And the second distinguishing feature is:
who has free will when somebody is time traveling. Like, whose actions are allowed to move history
onto a different trajectory, and whose aren’t? One of the simplest time travels is “do-over”
time travel, where you essentially get to re-play history starting exactly as it was
at a certain point, with the only caveat being you remember your experiences from already
having tried various possible future timelines (while no one else does). It’s essentially like playing a video game
where you can start a level over with the foresight of what you did wrong the first
time. For example, in Groundhog Day Bill Murray’s
character relives the same day over and over again, and though he can make different choices
each time, he always starts back at the same point (except with new memories of his previous
choices). That is, until he figures out the one exact
set of choices that frees him from the loop. I consider “A Christmas Carol” to be in this
vein, too, even though it may not seem like time travel. But because Scrooge gets to visit the future
of his current timeline, even though he has no ability to affect the timeline directly
while “visiting”, he can still change his actions in the present based on what he learns,
essentially getting a “do-over.” The video game Braid is built on the idea
of “do-overs”, where you get to rewind a few seconds and try something different
(though there are some things that are immune to going back in time and don’t “rewind”,
which is what makes the game interesting). Braid also has another kind of time travel,
where you go back to your past as a separate individual, and the past version of you is
there with no free will, just doing exactly what you did the first time around, while
“time-traveling you” can change the course of history. This is also how the video “Clock Blockers”
by the Corridor Digital youtube channel works. And then there’s time travel where the very
act of going to the past or future creates a fully new trajectory of history because
time-traveling you weren’t there the first time around, and now you are. This includes the typical “anything goes”
time travel movies like Bill & Ted’s Excellent Adventure, Back to the Future, Star Trek First
Contact, and so on, where you can kind of instantly jump back and forth to any point
in time you want, potentially resulting in multiple versions of yourself. From a causality perspective, anything you
do in the past (and even just the act of going back in time) redirects the course of history
onto a new timeline – in Back to the Future, Marty’s interference with his parents falling
in love results in the timeline of history being redirected towards a version of the
future where he doesn’t exist and so he starts to disappear from photos and real life. And even after correcting that major deviation,
his interactions with his parents while he’s in the past result in them being very different
people when he returns to his present time; he accidentally caused history to progress
in a slightly different direction. The movie ”Looper” is similar, but there’s
a little more circularity because when you jump to the past, you cause history to branch
onto on a trajectory where, in the future, the younger you also goes back in time the
same way you just did. Both you and your past self still have enough
free will to change that forward course of history, though, which results in weirdness
like you getting new memories when your past self does things you yourself didn’t do, or
if they lose a body part, suddenly you’ll lose it too, replaced by an old scar on your
own body. So, changes to the present affect not just
future timelines, but also future timelines that wrap back around to the present! The indie film Primer is in the same vein,
except that it takes the plot device of time travel to the extreme, with time travel within
time travel within time travel, time-traveling characters interacting with other time-traveling
versions of themselves, bringing time machines with them to the past inside other time machines,
and so on. But beyond the complexity, there are two things
that make Primer stand out: first, time travel to the past isn’t an instantaneous jump, but
actually takes time: to go back 6 hours, you sit in the time machine for what feels like
6 hours. And time travel can’t take you back to a time
before a given time machine was initially activated, since of course, the machine can
only be taking you back in time inside it if it’s turned on, so the first time it was
turned on is the farthest back in time you can go. There’s a nice logic to it. Which brings us to perhaps my all time favorite
of all fictional time travel: Harry Potter and the Prisoner of Azkaban. It’s an “instantly jump back in time” kind
of time travel that doesn’t actually generate any new timelines. It manages that because in this universe,
while you were experiencing your initial, pre-time-travel passage through a particular
point in history, your “time-traveling clone” was also already there, doing everything you’ll
eventually do when you time travel yourself. For example, Harry and friends are saved from
dying by their time-traveling selves, the first time through that timeline. It makes so much sense – if you go back
in time, you really and truly were present at that point in time all along! This also means that during the period of
overlap, the time-traveling you has no actual free will, since everything you do has in
some sense already been done, which Harry comprehends when he realizes he has to save
his past self because he was already saved by his future self when he was in the past. I think I love this kind of time travel because
it manages to be logically consistent: it’s time travel to the past where you can’t change
the past, because the past already happened. And there’s only one timeline – the one
in which time travelers arrive from the future, do stuff, and at some later date, leave to
go to the past. Logical consistency is a primary thing that,
you may have noticed, I think lays the foundation for good time travel stories – not because
logical consistency is important in an of itself, but because, most of the time, in
order to care about the characters in a story, we have to believe that actions have consequences. If everything is just a meaningless series
of events, then we almost don’t have a story. So it’s really helpful if there are rules
by which the universe of the story functions, whatever those rules may be. Speaking of actions with consequences, I finally
got the kick in the pants I needed to make this video from my friends at the Corridor
Digital YouTube channel. They’ve asked me to help promote their new
YouTube Red Original Series, “Lifeline”, which, minor spoilers ahead… is a sci fi
action thriller with time travel in it. What kind of time travel, you ask? Essentially, if somebody dies in the future,
that sends a message back to the present, which allows people to jump forward to just
before the time the person dies and change the trajectory of history from that point
onwards, averting their death. But as you might imagine, things eventually
go awry. Anyway, you can check out the first episode
of Lifeline for free on the Corridor Digital channel or by following the links onscreen
or in the description . And fun facts: I actually know the Corridor guys from back before MinutePhysics,
when I was doing special effects for the “freddiew” channel. We also all grew up in neighboring towns in
Minnesota and even competed against each other in high school sports , though we didn’t know
each other at the time. But enough trivia – go check out their
show!

100 Replies to “Time Travel in Fiction Rundown

  1. I loved your explanations. I just finished the second season of the German TV series, Dark. I think you would find it mind bendingly fascinating.

  2. Harry Potter time travel is not logical. What if harry just wanted to do the opposite of what he saw future him do. Then that would probably cause a paradox, since when he does the opposite, the other past him will do the opposite, and so on.

  3. DO NOT PRESS READ MORE IF YOU DON'T WANT TO SEE ENDGAME SPOILERS!!!

    Didn't they time-travel in endgame? I mean.. when hulk went to [REDACTED] for the time stone, she said the stones would create a different future if taken from their time, and then banner said that they would take the stones, then when they were done, they'd put the stones back. But, when they brought back the stones, a couple minutes later, Thanos comes through time and ruins the time machine, so the Avengers could not put them back. Explain, MP.

  4. I always get confused by this statement that in certain theories the time travelers can travel back to the time when the time machine was built. In short I always get confused about this explanation of spacetime geometry, that our past, present and future are actually existing somewhat simultaneously? But, then why can't we travel in time like we do in the spatial dimensions? Where are those past and future events? How can we travel back to a time when the time machine was built? Because, after the machine was built time passed at that point, and now, it's the present at that point. How time stopped at the moment the machine was built? And general relativity even doesn't talk about a higher dimension. I thought the usual theoretical concepts where time travel is talked about through wormholes, may be they are conceptualised through another dimension. But, then found that's not the case. And even if that was the case, this whole idea about passage of time being like stored images and time being like a video is so beyond my understanding. I think I should just stop thinking about it.

  5. 3:13 Bill & Ted is actually the self-consistent version of time travel where the future actions affect the past the "first" and only timeline instead of the "anything goes" like you said. Case in point, Ted's father can't find his keys through the whole movie because Ted from the future went back to the past (before the events of the movie) to place them behind the sign in front of the police station where he could pick them up at the moment that he thought to do that which was right when they needed the keys. All they had to do was remember to go back to the past after the events of the film for the keys to be there. We don't see anything in the movie that would even hint at alternate timelines like Back to the Future.

  6. I already loved Harry Potter's books, but now your video has thrown a new light: logical consistency! I think the whole series has a lot of that … thank you!

  7. Most time travel concepts are towards Einstein's relativity theory but not towards Planck's quantum theory. The latter might seem more logical if any, but does not allow for great movie plots.

  8. What about time travelling in Harry Potter and the Methods of Rationality? It's like time travel in original HP but on steroids

  9. Latest discovery on time dilation, fixed light speed and
    understand Algebra, then download this open access, no login,
    no ads, 2018 Cern archive journal paper.
    https://www.zenodo.org/record/1447218 or do login to
    https://www.academia.edu/37595209/Wenner_Time_Dilation_Ref_10_04_2018_1_.PDF

  10. LETS HEAR IT FOR SWEET HOME MINNESOTA!!!
    If you were born here, live here, or just think it’s great, let’s give our chilly state some love!!

  11. There is a time travel concept in Hindu Mythology… According to Hindus there are many world's Devs ie Gods live in Different world Asur ie Demons live in Different world.. There is always a War between Gods and Demons.. Once what happened the God's Required a good fighter as Demons were about to defeat them so they called a great king from earth… He agreed to join the Gods… So he faught for weeks and the Gods won the battle against demon now he wanted to return to his family… But the Gods explain him that there are different time zones in different world while he faught for 2 weeks in this world some 200 years have passed on Earth..

  12. Interstellar violated the BOOTSTRAP PARADOX. He only became a time traveler because his future self told him to.

  13. Considering the channel, I am a bit surprised that you prefer the time travel variant that removes all possibility of human agency. Possibly the concept of agency itself, yikes.

  14. my favorite kind of time travel theory is where like harry potter, your future self has already "changed" the past, so you, going back in time, is simply copying what your future self did. I also like a time travel theory where when you go back in time, you aren't directly in the past, moreso watching the past. Except, you're able to leave notes or signs of sort for your past self or anyone to find and possibly change their direction in life.

  15. If you travel to the future you have already done it. Time is in one line. No matter what. It’s already been done.

  16. Actually, the real question is if creating alternate timelines means that the original timeline and prior timelines to the current timeline no longer exist after the point of the time traveler goes back or forwards and if not, can they access the previous timelines?

    NOTE: Back to the Future is my inspiration for this version of time travel even though they couldn’t access all of the timelines. However, when Avengers: Endgame was released that was my perfect interpretation of time travel.

  17. What I get from this… what is in the future is going to always be what happens. So at no point on the timeline do we ever have free will.

  18. But in Back To The Futue, Marty couldn't change the timeline he lived on. Why would he disappear when the timeline he was born in still existed. In BTTF there is only one timeline.

  19. 4:24 another example is WTfuture from eddsworld were in it edd from the past hides in a dinner and future edd finds him because they share memories

  20. I think primer is definitely my favourite time travel movie that I've seen. Clearly the number one from this list. It's complicated so you have to focus and watch it multiple times to understand, but when you do it's pretty awesome. I find it really cool because it manages to be logically consistent, even though you put it in the "anything goes" category. (I think it has the most strict rules actually from the multitimeline movies) It also feels like it would be possible in the real world, it explains the science so well that at least I get the feeling I understand what it's doing and how it works and how they figured out that it's in fact a time machine. Compare it to BTTF's flux capasitor for example. They also thought first that it only blocked gravity, which is directly connected to time (gravity is just curvature of spacetime).

  21. In Marvel's Endgame they time travel too. Maybe you can make a video about that as well, this time travel makes alternate realities

  22. Have you ever read the novel Timemaster by Robert Forward. He is a particle physicist who wrote novels. Timemaster is about a billionaire industrialist who finds away to travel back and forward in time via wormholes.

    The book takes a different stance on time travel. It assumes that everything that happens in anyone moment is immutable. Any person from the future traveling there has always been there and time cannot be altered at all.

    In order to achieve this he handles time paradoxes in a unique way. Should you go back in time with the intent on changing the past what will happen is that wild circumstances are much more likely to occur to protect the timeline. For instance suppose you go back in time and kill your father before you are born. Then the probability that aliens will arrive and clone your father inserting him into your father's life will go from remote to very likely to a certainty. Some strange occurrence will happen which will make it appear to your past self that the timeline is intact. It has to because the past cannot be changed.

  23. His favorite timetravel plot is my least favorite. The no free will one is absurd to me, I would totally do something different if I go back in time even if it's just a wink so it wouldn't make any logical sense. Primer is the best time travel movie.

  24. Has anyone watched the infinite man it is imo the best time travel movie it’s an Australian film so I doubt this comment will be read by any one who has

  25. Time travel doesn't and never will exist how people think it will work. There are 0 time travellers appearing so no time travel

  26. I'd love to see this channel explain the time travel in Dark. I think it falls in the same category as Harry Potter, for now. But my whole problem with this is, if I travel to the past and do things that affect my past, when does it all begin? Like what's the starting point?

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