Which theory of time travel do you subscribe to?

[darkxshade]

Originally posted by: Atomic Playboy
Don't forget the other obvious theory: time travel exists in the future, but no time travellers want to come back to our time. Let's face it, if you had a choice between going and seeing the dinosaurs or going back and looking at 7th century France, which would you choose?

One flaw in that statement... you're assuming that all they want to do is to observe but unlike my statement B, they are in fact able to make changes. So if you believe that the past can be changed, then when and where they go is irrelevant. Why go back and watch dinosaurs when you can just build civilization from there? There are too many reasons to change the past and too many ways to do it and in the absense of any evidence of tampering to the timeline leads to my stated conclusions.

 

[DrPizza]

Originally posted by: Lamont Burns
two objects can't occupy the same space at the same time!

Multiple bosons can share the same space at the same time. And, of course, something can behave as if it's in two places at the same time.

 

[torpid]

Originally posted by: darkxshade
There are too many reasons to change the past and too many ways to do it and in the absense of any evidence of tampering to the timeline leads to my stated conclusions.

Your conclusions are based on the assumption that if time travel to the past were possible, human beings would necessarily achieve it and leverage it. That is quite a leap. We are speaking only in hypotheticals here, where we can guess about how it would work were it possible. It doesn't mean humans will ever achieve it. Your argument is similar to ones offered against the existence of aliens in the universe.

 

[Crono]

Unchangeable timestream. Everything in time is part of a story. Time itself, you could say, is the story. The only one who could change or rewrite time is the author.
Even if you could travel back in time, you can't change events.
You can't travel back in time, though.*




*I can, but that's another topic

 

[0roo0roo]

http://io9.com/5238315/6-theor...me-travel-in-star-trek
http://io9.com/5191092/10-diff...he-terminator-universe
http://io9.com/5228318/time-tr...ot-to-meet-your-mother

 

[SphinxnihpS]

There is no such thing as time.

 

[rudder]

You can only travel forward. If you remained in the same point in space long enough, eventually events would repeat themselves, but the future of those events is not exact so they could be changed.

 

[darkxshade]

Originally posted by: torpid

Originally posted by: darkxshade
There are too many reasons to change the past and too many ways to do it and in the absense of any evidence of tampering to the timeline leads to my stated conclusions.

Your conclusions are based on the assumption that if time travel to the past were possible, human beings would necessarily achieve it and leverage it. That is quite a leap. We are speaking only in hypotheticals here, where we can guess about how it would work were it possible. It doesn't mean humans will ever achieve it. Your argument is similar to ones offered against the existence of aliens in the universe.

And I'm saying hypothetically if time travel did exist that the absense of evidence in our world suggest that history cannot be altered. That's not to say that time travellers or time travel does not exist. I don't see how this is similar to the argument about existence of aliens.

 

[Modelworks]

The theory that every decision creates a different time line. Want to kill your father? go ahead, you killed him, you go about your day. Not you going poof because you killed him so you can't be born.
Easiest way to imagine it is two types of time, what it local for you, and what everyone else experiences. Whatever happened last for you personally is what you perceive as time. No two people would see the same thing.

I can't go into more detail, but there is going to be a great scifi movie coming out this winter that deals with that very subject.

 

[StinkyPinky]

I believe it to be impossible to travel into the past. The timestream is only one way - and that's forward. So you can skip forward but not back. Isn't that what our current understanding of physics also suggests?

That would also explain why we never see any time travellers because no one has invented it. So once it is invented (if it can be) we will begin to see travellers from the past, but never the future.

 

[Modelworks]

Originally posted by: StinkyPinky

That would also explain why we never see any time travellers because no one has invented it. So once it is invented (if it can be) we will begin to see travellers from the past, but never the future.

Who is to say they haven't already traveled back in time and this is the future they wanted ?
We tend to assume that people in the future would travel back and change life for the better, but what if the people that traveled back did not want that ?

If you are from the future, chances are you would know what places are empty of population, enough that you could come back without ever being noticed.

 

[Crono]

I'm actually in the process of writing a novel that partly deals with this issue.
The resolution of it is that time is linear, but can be split off ("parallel" timelines) that remain partly connected, like the rails in train tracks. In other words, there is some resilience to timelines, but you cause enough damage to the "fabric" of time, and it will split, even more damage, and it will branch out. In the novel, though, the characters are looking for a way to stitch back the timelines by undoing the "knots" in time and pulling together the parallel timelines.

 

[torpid]

Originally posted by: darkxshade

Originally posted by: torpid

Originally posted by: darkxshade
There are too many reasons to change the past and too many ways to do it and in the absense of any evidence of tampering to the timeline leads to my stated conclusions.

Your conclusions are based on the assumption that if time travel to the past were possible, human beings would necessarily achieve it and leverage it. That is quite a leap. We are speaking only in hypotheticals here, where we can guess about how it would work were it possible. It doesn't mean humans will ever achieve it. Your argument is similar to ones offered against the existence of aliens in the universe.

And I'm saying hypothetically if time travel did exist that the absense of evidence in our world suggest that history cannot be altered. That's not to say that time travellers or time travel does not exist. I don't see how this is similar to the argument about existence of aliens.

Hypothetically if time travel did exist, absence of evidence in our world has no bearing on how it might work. All that it has bearing on is whether anyone has gone back in time and visited planet Earth. Time travel could permit altering the past. Assuming that it has never happened on planet Earth, it doesn't mean it can't happen or hasn't happened elsewhere.

The argument about existence of aliens is very similar. If aliens exist then why haven't they visited us yet? Same basic fallacy.

 

[Crono]

Originally posted by: torpid

Originally posted by: darkxshade

Originally posted by: torpid

Originally posted by: darkxshade
There are too many reasons to change the past and too many ways to do it and in the absense of any evidence of tampering to the timeline leads to my stated conclusions.

Your conclusions are based on the assumption that if time travel to the past were possible, human beings would necessarily achieve it and leverage it. That is quite a leap. We are speaking only in hypotheticals here, where we can guess about how it would work were it possible. It doesn't mean humans will ever achieve it. Your argument is similar to ones offered against the existence of aliens in the universe.

And I'm saying hypothetically if time travel did exist that the absense of evidence in our world suggest that history cannot be altered. That's not to say that time travellers or time travel does not exist. I don't see how this is similar to the argument about existence of aliens.

Hypothetically if time travel did exist, absence of evidence in our world has no bearing on how it might work. All that it has bearing on is whether anyone has gone back in time and visited planet Earth. Time travel could permit altering the past. Assuming that it has never happened on planet Earth, it doesn't mean it can't happen or hasn't happened elsewhere.

The argument about existence of aliens is very similar. If aliens exist then why haven't they visited us yet? Same basic fallacy.

The question is whether you want to take the philosophical approach or the scientific approach. Philosophy demands no physical evidence. Science does. If you say philosophy, then you can content yourself with many ideas, no problem. But if you are going with science, you have to ask the question "what would prove time travel can or has occurred", and then you would need to go about looking for existing evidence or create an experiment that can prove or disprove the possibility of time travel.

At this point, time travel (meaning really travel back in time, as we know traveling forward is not a problem) may be non falsifiable. You can't disprove the existence of aliens, because you cannot search the entire universe.

 

[darkxshade]

Originally posted by: torpid

Originally posted by: darkxshade

Originally posted by: torpid

Originally posted by: darkxshade
There are too many reasons to change the past and too many ways to do it and in the absense of any evidence of tampering to the timeline leads to my stated conclusions.

Your conclusions are based on the assumption that if time travel to the past were possible, human beings would necessarily achieve it and leverage it. That is quite a leap. We are speaking only in hypotheticals here, where we can guess about how it would work were it possible. It doesn't mean humans will ever achieve it. Your argument is similar to ones offered against the existence of aliens in the universe.

And I'm saying hypothetically if time travel did exist that the absense of evidence in our world suggest that history cannot be altered. That's not to say that time travellers or time travel does not exist. I don't see how this is similar to the argument about existence of aliens.

Hypothetically if time travel did exist, absence of evidence in our world has no bearing on how it might work. All that it has bearing on is whether anyone has gone back in time and visited planet Earth. Time travel could permit altering the past. Assuming that it has never happened on planet Earth, it doesn't mean it can't happen or hasn't happened elsewhere.

The argument about existence of aliens is very similar. If aliens exist then why haven't they visited us yet? Same basic fallacy.

Again, I never said time travel can't happen. I'm saying it can but the lack of evidence(at least in our case) leads me to conclude (again in our case) that A. Time travel doesn't exist(I know this part is contradictory) or that our civilization does not survive long enough to discover it or B. That we did discover it but are unable to alter the timeline. This is short of creating alternate universes which we cannot begin to comprehend.

The difference between this and aliens is that there are valid reasons why they have not visted us yet(I personally believe they do exist by the way). They may very well exist but they can't visit us because they don't have the technological means or maybe because the universe is so big that finding us is harder than finding a needle in a haystack. However on the time travel bit, if *we* in the future discovered time travel, there should be no reason why there is no evidence to suggest history has been altered.

 

[Oceandevi]

You can travel to the future using a very fast spaceship... but everyone knows that.

 

[Cerpin Taxt]

Originally posted by: SphinxnihpS
There is no such thing as time.

This, more-or-less, but the way you phrased it is kinda like saying there is no such thing as longitude and latitude. The coordinates are real, in that they are real ideas, but they are not features of external reality.

 

[Oceandevi]

Originally posted by: Cerpin Taxt

Originally posted by: SphinxnihpS
There is no such thing as time.

This, more-or-less, but the way you phrased it is kinda like saying there is no such thing as longitude and latitude. The coordinates are real, in that they are real ideas, but they are not features of external reality.

Entropy is very real

 

[Modelworks]

Originally posted by: darkxshade
However on the time travel bit, if *we* in the future discovered time travel, there should be no reason why there is no evidence to suggest history has been altered.

But if the future people can time travel, wouldn't they be able to keep traveling back and fixing time anytime that people found evidence to suggest that history had been changed ?

Unless they were caught in the act, our history is our history to us and if they changed it, we would not realize it had changed.

 

[TwiceOver]

So... There's this pair of ducks...

I'll go with option 4, you can't do any of the above.

 

[TestedAcorn]

Time is something we made up. There is no way to physically reverse the cycle in with the earth has spun, and go back to previous events.

 

[Modelworks]

Originally posted by: TestedAcorn
Time is something we made up. There is no way to physically reverse the cycle in with the earth has spun, and go back to previous events.

I guess that the time corrections they have to use every day to keep the gps system working are made up. Required because the difference in gravity causes time to be different on the satellites vs time on the planet surface.

 

[DrPizza]

Not sure if anyone's mentioned it, but one proposed mechanism for time travel involves opening up a stable worm hole. You could only travel back through time until the point at which time travel was invented. If you go to scholar.google, there are plenty of articles on various mechanisms through which travel through time seems possible. Search for Godel as one of your search terms for one of the first hypotheses.

 

[bunnyfubbles]

Originally posted by: JS80

Originally posted by: jonks

Originally posted by: soulcougher73
Id fall in the #2 option. Can change the past. Seems simple if you were to just go back and kill Martin Luther King for example at an early age. Not to say what he did would not ever come to fruition, but it may be delayed for years.

But you didn't kill him, since he lived

Sayid tried to change the past by killing Ben as a child, but since we know Ben grew up to be an adult, clearly no one managed to kill him in the past, hence Sayid failed to kill him.

So does that mean Ben knew this whole time that Sayid was the one that shot him when he was a child?

no he didn't remember, because they had the island revive him and it was explained that the process involved to do so would include him not remembering being shot at all (let alone who shot him), it is also supposedly what changed Ben from an innocent boy into the conniving character we know.

 

[torpid]

Originally posted by: darkxshade
Again, I never said time travel can't happen. I'm saying it can but the lack of evidence(at least in our case) leads me to conclude (again in our case) that A. Time travel doesn't exist(I know this part is contradictory) or that our civilization does not survive long enough to discover it or B. That we did discover it but are unable to alter the timeline. This is short of creating alternate universes which we cannot begin to comprehend.

You directly stated that the only way to have a serious discussion was to base it on assumptions about our existing history. This is not a reasonable method of answering the question because it requires discarding the option that time travel is possible but we don't achieve it to any serious degree. I am pointing out that it is the opposite of a serious discussion because it discards the question being proposed itself by requiring us to frame it in this light.

The difference between this and aliens is that there are valid reasons why they have not visted us yet(I personally believe they do exist by the way). They may very well exist but they can't visit us because they don't have the technological means or maybe because the universe is so big that finding us is harder than finding a needle in a haystack. However on the time travel bit, if *we* in the future discovered time travel, there should be no reason why there is no evidence to suggest history has been altered.

The same applies to time travel. If time travel is possible we may not have the technological means or maybe the particular mechanisms are such that it is impossible to find Earth because of the expansion of the Universe and inexact nature of time travel. There really is not much difference in your reasoning. If OP asked whether aliens would look exactly like us or if they would look other-worldly, your reasoning could be applied pretty easily.

Anyway, your conclusions don't really match either model. In both models, it is possible for someone to go to the past, do some stuff, and then claim they are from the future. In the Faraday model, this would have already happened and we would currently be thinking of such an event. Not sure about BTTF but probably something very similar. In the Faraday model, since you remember your father, it's not that you CAN'T go back in time to kill that person, it's that you DIDN'T do that particular thing. Nothing prevents you from doing it. If you go back with the intent of killing daddy, you won't end up doing it. It's a model fraught with serious philosophical issues relating to free will and determinism. You have free will, but your brain has already processed the result of your choices.