Some ideas are:
- You branch off into another timeline and your actions make no difference to the previous timeline
- You’ve already taken said actions but just didn’t know about it so nothing changes
- Actions taken can have an effect (so you could suddenly erase yourself if you killed your parents)
- Only “nexus” or fixed events really matter, the timeline will sort itself out for minor changes
- something else entirely
I really like the nothing is changeable and travel is possible and anything you do while traveling has already happened / was already going to happen concept
I wouldn’t say I “like” the idea, since it’s one of the most doomed ways for a universe to be, but Greg Egan’s Arrows of Time is a good exploration of this idea.
Its a one way trip. You can never go back to the original universe.
Holy existential horror, Batman! By time traveling, you’ve just caused an entire universe full of new alternate-timeline versions of people to pop into existence. What happened to the timeline you left? It must still exist. You couldn’t have been the only consciousness that was experiencing it. To think otherwise is some extreme solipsism. Gosh, did some other time traveler create the timeline you left by entering it? For that matter, are you actually a duplicate, having just popped into existence with the memory of having time-traveled, but the timeline was created by another time traveler?
Alternatively, perhaps it’s another timeline out of an infinite number of possibilities that all co-exist? Yikes! That means there’s an infinity of each person across the multiverse. Therefore, you could just murder everybody within reach, and time travel back before your started the rampage. The lives in a particular timeline don’t matter, there are an infinity more. I think Rick & Morty did an episode with that premise.
What happened to the timeline you left? It must still exist. You couldn’t have been the only consciousness that was experiencing it. To think otherwise is some extreme solipsism.
Why does it need to remain? It seems like solipsism to assume it must remain because it’s your point of origin. If something or someone has the power to drop something into the past why wouldnt it overwrite everything? I don’t see why consciousness even gets applied. The universe keeps on whether I am alive, asleep, or dead.
I see the path of time like a laser beam in a house of mirrors. If someone has the power to add a mirror somewhere. Yep, the whole beam after the fact is a vastly different pattern. Any multiverse would be entirely virtual and theoretical.
Why does it need to remain? Because that timeline was populated by 8 billion human, and who knows how many non-human minds. I think it would be solipsism to think that only your own mind was the “real” one keeping the timeline in existence, and it collapsed because you leave it.
If the time travel power does overwrite everything, all of those minds and all of their subjective experiences are just, nothing? That’s where the existential horror comes in for me.
Oh I agree, it’s horrifying. And I have noooo guarantee that it’s me doing the jump. Don’t misunderstand I am NOT the only real mind in this example. I’m curently just hitching a ride on said laser beam. No guarantees that I will be the same or even exist if somebody so much as moves a pebble into the past from the future.
Existential dread all the way. If we get time travel I think it’s as horrifying a prospect as teleportation on a universal scale with only the traveller maintaining continuity.
This is my biggest issue with multiverse time travel in popular culture. Somehow they always travel back and forth between 2 of Infinite timelines
I don’t need anymore subscriptions, thank you.
Time travel does exist, but you can only go forward. You just need to approach the speed of light relative to a frame of reference, and you will travel a shorter time span compared to it.
From a narrative sense the “nexus” theory is certainly the most amusing, which is probably why Terry Pratchett posited it works exactly that way on numerous occasions. It turns out that history really is kings and battles and speeches and dates, and in order for history to have actually happened someone has to observe those critical events. The things in between really don’t matter. History as a whole further finds a way of happening whether people are involved in it or not, and regardless of – or possibly despite – anyone attempting to hinder, help, or change it. The key events will always happen eventually. All anyone can do is slightly influence how long it takes for them to do so, which is why there are so many boring spans in history where it seemed like nothing really happened; That’s because it didn’t. Possibly until some history monk noticed, and came along to pull out whatever spanner was holding up the works.
- You branch off into another timeline and your actions make no difference to the previous timeline
New actions, new consequences.
This. Time traveling is a purely selfish endeavour.
Go back and kill Hitler? Congratulations! Only you understand what changed. Doesn’t help the 7 billion people you left in your original timeline.
But you now get to live in a cool alternate reality where the soviet union clashed directly with the allied forces as the axis never existed.
. . .
Kirov reporting.
Probably the branch off one.
Though, speaking of time travel, I really don’t understand/like the whole Harry Potter dementor (however it’s spelt) lake scene in the movie where future Harry saves past Harry. How does that work? Wouldn’t in an initial timeline Harry have to somehow save himself before he could travel back in time to save his past self? The way I see it, it just looks like an infinite cycle of Harry saving his past self with no origin point.
That’s called the bootstrap paradox if you want to look that up.
My personal favorite?
Space and time is an infinite number of parallel realities that constantly compress and unravel at every possible random chance. We are 4th (or 3.5th) dimensional beings that experience the most probable result aggregated from an infinite existence. If you time travel back in time, and change the past, it would not affect the your past, but it would affect your future, if you time traveled back to your current time.
I subscribe to multiverse theory. It’s probably the safest route and probably most likely.
My belief is if you went to the past your actions would fully effect the future, no branches or anything else of course this will create paradoxes but if your a time traveller you will still exist even if you prevent your birth, if then you go back to the future there will be no record of your existence.
Hope that makes sense.
In either scenario, I’m more interested in where the matter you’re made of will come from:
- Either you go to the past and suddenly add additional atoms to the universe.
- All the atoms you’re made of will suddenly be taken from their origin to form you.
- You’ll be made from entirely new atoms created from pure energy meaning your arrival will cost ~6.75 Quintillion as in 10^18 Joules (I eyeballed the speed of light here so don’t @ me).
Branch off probably
I like the idea that the timeline you exist in is that and can still be determined but everything that happened in the pasr is set in stone. Future time travel is not possible.
The current scientific theory is that time exists across space in cones that would require one to move faster than the speed of light to alter. Going to go with that one for now since I have no idea personally.
Light cones aren’t exactly literal cones of time, they are an abstraction to help us understand the mathematics of time and space. (Assuming you are talking about Penrose diagrams.)
Yes, it was light cones. I was half remembering the uni module I did on the philosophy of time a decade ago. We spent more time on the grandfather paradox than the actual science!
I think time travel as a being who perceives one dimensional time linearly is not possible. And for any entity who doesn’t perceive time linearly it would be no different from traveling in a spacial dimension. It’s just travel. Anything that entity does in that point is a permanent fixture to the entities that perceive it linearly.
So yes, if someone could travel in time in the SciFi sense, they wouldn’t be able to change anything in their past experience (direct experience or prior to their perception, but in their event line) because that’s already part of that point in spacetime to anyone who experiences it linearly.
But also, it’s likely that time is not one-dimensional just like we know space is not only three-dimensional. So it is possible that you could end up in a separate “branch” of time that your past self from your perspective will never experience (directly or as past events), because it’s not the same point in spacetime as the event in your direct past timeline. But it’s not like there is a specific set of “branches”. They likely don’t branch off from a single trunk into the other dimension(s) or if they did “branch”, it was at the same time as all other “branches”, the beginning of the universe, not as specific events occur like in SciFi. And the changes you make in those branches were always part of those branches to people who will perceive the future of that timeline.
