Time Travel - Paradoxes and How to Avoid ThemsteemCreated with Sketch.

in technology •  2 years ago

Traveling Through Time.

When I was a kid I watched a lot shows that had time travel in it, particular Dr Who, and thought that it would be pretty nifty to have a time machine. But when I started to think about this a little further, I came to the realization that it was rather impossible. One, if we have developed a time machine at any point in the future we would already be aware of it because they would have visited by now. And two, due to the nature of time or at least my understanding of it at that point, it would break some things.

But lets suspend our disbelief for a moment and assume we have a working time machine chilling in the back yard. What are some of the issues we might run into when journeying through time.

Predestination Paradox

A Predestination Paradox happens when the actions of the person traveling back becomes part of past events in their timeline, and may influence the event they are trying to prevent and cause it anyway. This results in a loop in which Event 1 in the past influences Event 2 in the future (the time travel) which then causes Event 1 to occur. With this circular loop of events ensuring that history is never altered by the individual. That any attempts to stop something from happening in the past will simply lead to the cause itself rather than stopping it. This paradox suggests that things are always destined to turn out the same way (pre-destiny), and that whatever has happened must happen.

Sounds convoluted? Well here are a few examples. Say your friend dies in a car accident and you travel back in time to save them from that fate. Only to find out on the way to the accident that the interactions you had going there influenced them to step in front of the bus you were riding on. Your attempt to change that outcome directly influenced the events and lead to a predestination paradox. One way of dealing with this type of paradox is assuming that the version of events you have experienced already are leading up to the choice of going back into the past. And that by doing so you will only end up fulfilling your role in creating an event in history instead of changing it.

This is summed up quite nicely a quote from the movie "The Time Machine".

“You built your time machine because of Emma’s death. If she had lived, it would never have existed, so how could you use your machine to go back and save her? You are the inescapable result of your tragedy, just as I am the inescapable result of you.”

Bootstrap Paradox

A Bootstrap Paradox is slightly more complicated, and entails a person, object, or piece of information sent back in time resulting in an infinite loop where the object has no identifiable origin, and exists without ever being created. For example a person traveling back in time and giving themselves the script for a movie which they go on to create and earn great fame would create a bootstrap paradox involving information. As the script has no true point of creation or origin.

A paradox event involving this particular one could happen if a 20 year old male traveler goes back 21 years, meets a woman, has an affair and travels home without knowing the woman was pregnant. Her child grows up to be the 20 year old time traveler who travels back 21 years, meets the same woman, and so on.

These bootstrap paradoxes imply that the future, past and present are not defined. Giving scientists an obvious problem on how to pinpoint the 'origin point' of anything. A word generally used to refer to the past, but is now rendered meaningless. This leads us to question how the object or data was created, and by who.

Grandfather Paradox

This time paradox would be caused if time was linear. Say if you traveled to the past and killed your grandfather, you would never have been born and would not have been able to travel to the past. So you decided to travel back to wipe out your own grandfather before he sired your father who he went on a murderous rampage. Figuring that if you remove him from the timeline before he meets your grandmother the whole family line will vanish and the world will be a better place. According to theoretical physicists, the situation could play like this:

Time line protection hypothesis: You pop back in time, walk up to him, and point a revolver at his head. You pull the trigger but the gun fails to fire. You point the gun elsewhere and pull the trigger. Bang! Point it at your grandfather.. Click! Click! BANG! The bullet mysteriously ricochets off a speck of dust in the air, rebounds off a wall and hits you instead. Game over man, Game over.

Multiple universes hypothesis: You pop back in time, walk up to him, and point a revolver at his head. You pull the trigger and Boom! The deed is done. You return to the “present” but you never existed here. Everything about you has been erased. You’ve entered a timeline where you never existed. Either you have created a branching timeline where you have just popped into existence or slipped over to some kind of parallel universe.

Polchinski’s Paradox - Of Billiard Balls

American theoretical physicist Joseph Polchinski proposed a paradox in which a Billiard ball enters a wormhole. Then emerges out the other end in the past just in time to collide with its younger version and stop it going into the wormhole in the first place. This particular paradox is taken seriously by physicists, as there is nothing in Einstein’s General Relativity to rule out the possibility of time travel. It has the advantage of being based upon the laws of motion, without having to refer to the concept of free will and so presents a better research method for scientists to think about the paradox.

When Polchinski proposed this paradox, he had the Self-Consistency Principle in mind, which basically states that while time travel is possible, time paradoxes are forbidden. However, a number of solutions have been formulated which involves the ball interacting in a way that changes its younger version’s course, but not enough to stop it entering the wormhole. This solution is related to the ‘timeline-protection hypothesis’ which states that a distortion would occur in order to prevent a paradox from happening. This also helps explain why if you tried to time travel and murder your grandfather, something will always happen to make that impossible, thus preserving a consistent version of history.

Are Time Paradoxes Inevitable?

The Butterfly Effect is a reference to Chaos Theory where trivial changes can have huge cascade reactions over long periods of time. Consequently, the timeline corruption hypothesis states that time paradoxes are an unavoidable consequence of time travel, and even insignificant changes may be enough to alter history completely.

For example just interacting with the way the wind blows in the past might cause a cascade event where a hurricane takes place in your home town thousands of years into the future, wiping out your entire family on your return to the present.


Scientists eager to avoid the paradoxes presented by time travel have come up with a number of ingenious ways in which to present a more consistent version of reality, some of which have been touched upon here, including:

  • Time travel is impossible because of the very paradox it creates.

  • Successfully altering events in the past will set off another set of events which will cause the present to remain the same.

  • An alternate parallel universe or timeline is created each time an event is altered in the past.

  • A person traveling to the past would exist in the new timeline, but have their own timeline erased.

I know this was a big one, and I thank you for your patience in getting through it. Hopefully you had as much fun reading it as I did writing it up.

Much love dearest readers, hope you all have a great day. <3
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Avoid time traveling paradox is quite simple.
just don't time travel XD




I already didn't twice! And it was super cool!

🎶My head is spinning like a carousel...

When I was a kid, I would spend countless hour's getting high and talking about time travel. I miss those days


Sounds like a great way to spend the day.


Oh it was! I came to a conclusion which has helped me through the years. Everything that was, is and will be again.


Yes, time is cyclic, I wrote a post about this actually. Or well, hinting at it.



I quite enjoyed reading that. I have always been of the impression that the universe is like a DVD where time/matter is just the data on a loop in a video store with every copy.

Taking my view time travel is quite possible but also redundant. Like skipping back to an old scene from a movie that will still play out the same regardless.

So let's say I travel back to kill Hitler and succeed. What happens to present as we know it? It should lead to a different now. But if that different now is not now then it must be somewhere else. On a different dvd


It really depends on how time operates, either you will be on a new disk, with the timeline changed, you would fade from existence, or have no identity, no friends, no family, perhaps even slip out of phase with the new timeline, or no matter what you do hitler will just be unstoppable, like by killing him he will just be cloned and go on to do whatever anyway.


Unless that disc is already there and data moves from one to another. So the me from disc A travels back in time to disc A Hitler and kill's him. From that point I will cease to exist from my time of departure. Nothing in disc a's past will change. When I kill Hitler in Disc A I am simply moved to disc B.

I do not consider disc B to a new disc but just another variation of disc A which already happened

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Every time I watch a movie with time travel my head slightly explodes from confusion. Perhaps reading this post upon waking up was not the greatest idea, but you did throw some coffee grounds in my mouth so that was helpful. :)
Seriously though, you did an excellent job explaining the different paradoxes!


Thanks for taking the time to take a look isaria, you are awesome even with all the bed hair. <3

Ah, a Polchinski reference...upgoat eminent :)

I like the idea of infinite realities being created at each disruption point. Almost summons a Merkel Tree-esque situation. Blockchain all the way down :)


Thanks for the support!! <3

This one was a real twister to write up. Much spirals.

Is it gay if you go back in time and have sex with yourself?


I believe they call that masturbation.

a big and many informative post @sammosk



Everyone knows you need a delorean for successful time travel.

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OK BUT maybe time travel does exist in the future and the visits have been super discreet. I think some of the Mandella effect examples could point to visitors from the future muddling around. I mean, it's impossible not to change ANYTHING. Either way, good post!


I think as soon as you pop in you are disturbing the natural order of things, and potentially wrecking the time line.

Unless it was meant to be and it forms an alternate branch... or the cause is the effect is the cause.. or you exist out of phase with the timeline you visit so you never actually interact or.. mind explodes

Thanks for commenting! I'll be scrubbing brains off the walls for weeks. <3


hands sponge have fun! hahah

Very informative article. Thank you for her.


No worries.

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upvote and comment plz

Time travel is indeed impossible. Though, to simulate an actualized past is not, nor is to simulate a potential future. Technological innovation will never advance to the point that time travel is possible, but it may advance to the point that we can walk through our past as it happened and interact and alter events in a simulation, as well as experience a calculated potential future, and these could be experienced as "real" as our present moment is now.


Yeah the simulated reality is far more probable. Time travel forward is indeed possible, but backwards? Ehhhhh.. Not so convinced we will ever get there.

I remember reading this in 1943. It was classic then too.

One of my favorite time travel books was 11/22/63 by Stephen King, which was then made into a mini series on Hulu and starred James Franco. Very well done, uses the "alternate timeline" theory of time travel.


I'll have to check it out, SK is one of my favorites.


I was going to recommend it as well!


Oh yeah, that was really good.

Successfully altering events in the past will set off another set of events which will cause the present to remain the same.
I never thought this one. I like it


Haha I quoted everything


Whoops!! Yeah that one is interesting, the self healing timeline. :)

Hello steemit

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I am from the future, and I endorse this post.

Now where is my LSD?


I hear some fancy cars have limited slip diffs. :D

Well that was amazing and so well written. Never thought about time as, the inescapable result of your tragedy, just as I am the inescapable result of you.

More so in the idea that time is always moving forward. Even if, you tried to time travel and murder your grandfather, something will always happen to make that impossible, thus preserving a consistent version of history.

As you explain time is not a fragment of time that we can adjust or alter without ripples affecting other aspects of life.

Way to,suspend our disbelief for a moment and allow our minds to travel with the idea of time travel. See what I did there :-)


From the end to the beginning, everything is cycles. (in my opinion)

Thanks for taking the time to comment kubby, I hope you have a wonderful day. Much love <3


It shall be wonderful indeed, have a good one sammo!

So i finally got time to study it. I did not want just to run through as this topic is interesting to me. I personally believe (like that matters lol) that any interaction with the past would create a hard-fork (yes yes just like crypto) and they both continue their ways after a split. So basically you can not change the predestined future in a given universe but just crate an alternate reality that can be forked further. That might be the reason why we are never visited, or we are visited but such a visit results in a fork that we are unaware of. Theoretically number of states an atom can exist is limiteles until it is measured so scaling is not an issue here.

Another theory i have that time travel or recreation of past or modelling future might be possible. Recreation (travelling back the timeline) actually being easier due to collected data that can be traced. BUT. You can not change it since matter can not travel back in time or it will create a fork. But you can effectively see past and probably future without a chance to change or influence it. Knowing of a climate change and visible obvious facts does not have major change how people behave, does it? So if such a grand scale foreseeable fact does not influence our current behavior why do we need any detailed predictions. This second part is more philosophical one. The first one being very real and practical i believe :DDD


I think it is possible to trace the past and with enough data influence the future to go the way you want it to go, which in some ways is time manipulation but not so much travel. However if you are talking simulated realities then anything is possible within the boundaries of the simulation.

Why does such a grand fact not influence? because money, costs money to enact change.

Thanks for taking the time to read over this. Hope you have a wonderful day. <3


Manipulation or travel itself is just a different form of medium... I believe that timeline itself is linear in any given fork and the number is infinite. It costs moneybto start a war too. Why it is so easy then?:) Since it is deeply phylosophical it could continue infinitely :) I have genuinely enjoyed the read, thank you for sharing and will be waiting for other posts to dig in :)

fascinating post ! thanks for sharing your ideas on time travelling, I have been obsessed wit Back to the Future during years and even now I am tracking every movie about it, best in date Predestination of course. :)

Time can bend but going back is impossible as paradoxes arise.

Ahh you write such interesting things. But I have to not read them in the morning, because it takes me less time to read the lot than to understand it XP

Did not know there were different types of paradoxes :O I'm going to be paradoxing all day now.

Cause before effect, now that is really going to ruin my dream! Steven Hawking has always said that time travel into the past is impossible. Oh, quantum mechanics, alternate universes.

Then there is the age-old paradox: if a man goes back in time and kills his father, how could he ever be?

Superb write, Sam. bangs head It made me think too much. :)

Upped and Steemed

Time travel is one of the things I am really interested in. There are only 2 things that I can think of that I would want to change if going back in time. I'm not sure that either of them would alter history too much, maybe though. I'd like to go back in history to be able to observe and take notes of things that our history "experts" are not too sure about. Great post. I upvoted and definitely will follow.

Very interesting and timely article for me. I have recently resumed an old hobby of writing time travel stories - it's a subject which has always fascinated me - and there are only a few examples of good time travel stories which don't break down due to the inherent paradox at their core.

I believe that I have finally come up with a new way to approach the problem. It is based on a non linear, multidimensional understanding of Time , coupled with a certain factor of randomness accompanying each crossing from one dimension to another.

I am testing it out here in this story:


(That’s the most recent part. If you like, you can work your way backwards to the earlier parts. In a non linear view of time, it makes little difference )

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The real gold is in the comments. Haha I love it.

In the multi worlds theory every possible outcome happens and the universe splits with every choice so I guess if you believe In that then you believe in time travel.


I like that, engagement is worth more than any upvote to me.

I think the multiple world theory is possible, but not probable.


Old Age is the last enemy any of us can hope to face..
When at long last there is no future to look forward to, then it is time to slip into the ether, and Open the next door ...
Never going back - Forward Forever..

Forever Forward.


please follow me.

This was so much fun to read, and despite all the paradoxes... I'm ready to go lol.


You are already a time traveler. We are traveling moment by moment into the future! <3

I remember some smart person said ( sad that I dont remember the name so I can quote) that if humanity will get ever to time travel we will already know since they will probably visited us.

Time travel always makes my head hurt but I agree it doesn't seem possible or if it was it would mess everything up. Have you seen the movie time crimes? It's Spanish I think you would really like it!


Never saw that one, but I'll take a look.

Thanks for the support! <3