Time Travel/Paradoxes

[SoulBlazerFan]

I've always been interested in time travel, whether it be movies or just thinking about the possibility.

Time travel is, obviously, impossible. However, lets leave that behind, and discuss some paradoxes from famous movies, shall we?

Terminator:

Anyone whose seen this movie knows how it goes. Killer machine from the future sent back to kill the mother of the future resistance leader. Father comes from the future to save the mother, they make baby.

Well, there's an issue here.

Consider the timeline. There at one point had to be a John Conner that was born with a different father. In this timeline, no Terminators ever came back. The world ended on August 29th 1997. When the first Terminator was sent back, a new timeline was created, 1984A, where Kyle Reese becomes John Conners father. Judgment day is stalled, but not stopped- meaning the messiah John Conner from the original timeline is a completely different person, and, perhaps, not the savior Kyle Reese prophezied him to be.

Back To The Future

Eh- so many. Think about this. 1955 Doc Brown knew the following, and did nothing to stop it;

in 1985, he was shot by the Lybian terrorists. While he did effect this event by wearing a bulletproof vest. However, 1955 Doc Brown learned the following; that Biff Tannen 2015 would steal the DeLorean and go back to 1955 and give it to his younger self, and make an alternate history where he is rich, powerful, and murdered Marty's father.

He also learned he would be struck by lightning in 1955 and sent back to 1885- and murdered by Buford "Mad Dog" Tannen, and knew nothing of what might happen afterwards.

I guess we can chalk this up to Doc Browns unwillingness to alter the future- but he still decides to build the time machine anyway.

Eh, this was just something off the top of my head.

[EverPhoenix]

most movies that involve time travel aren't too well thought out. the point with the original terminator movie is a good one - initially there would have had to be a different john connor to send kyle reese back.

there was one discussed in the Big Bang Theory, where leonard wanted to go back in time several minutes to hit sheldon, to prevent him saying something. as such, if he did hit him, there would no longer be the motivation to do so, and he wouldnt actually have any reason to hit him.

[SoulBlazerFan]

most movies that involve time travel aren't too well thought out. the point with the original terminator movie is a good one - initially there would have had to be a different john connor to send kyle reese back.

there was one discussed in the Big Bang Theory, where leonard wanted to go back in time several minutes to hit sheldon, to prevent him saying something. as such, if he did hit him, there would no longer be the motivation to do so, and he wouldnt actually have any reason to hit him.

Some people believe time is a loop- it ends and begins again, and follows the same path. Believing this, you're not actually time traveling- you're just living through an identical history, so theoretically speaking time travel would be possible- you'd just be traveling through a huge amount of time to an identical history, which is possible to change.

That Terminator one had been bothering me for quite some time. If John Conner B only existed after John Conner A... man, paradoxes are so ridiculous.

[EverPhoenix]

that would be why they are called paradoxes. ive had discussions with my friends about the nature of time travel (although, being completely honest, alcohol was involved most times so the discussions were more tripping out and less philosophical thought), and we've arrived at a couple of theories.

time is like another dimension. it has linearity. so, assuming you could move in time, you could move back to see things as they were, but with you as you were then. which, if considered, wouldnt be time travel. it would be reliving past events, with the possibility of making different choices. travelling into the future this way would be highly unstable, as the choices which shape the future are yet to be defined, and almost anything could happen.

travelling as a third person could also be interesting, but that would mean you could observe yourself, and have an influence on past events with knowledge of the present/relative future. dangerous thing about this, though, is that your observer form is based entirely on what you were like then. so, if anything you do changes your environment, you could potentially change in ... unexpected ways. mental instability, memories, etc etc.

it is all a really confusing thing to think about, but can lead to some amusing discussions. especially if there is some form of social lubricant involved. (yes, yes, i do like having a few drinks)

[SoulBlazerFan]

that would be why they are called paradoxes. ive had discussions with my friends about the nature of time travel (although, being completely honest, alcohol was involved most times so the discussions were more tripping out and less philosophical thought), and we've arrived at a couple of theories.

time is like another dimension. it has linearity. so, assuming you could move in time, you could move back to see things as they were, but with you as you were then. which, if considered, wouldnt be time travel. it would be reliving past events, with the possibility of making different choices. travelling into the future this way would be highly unstable, as the choices which shape the future are yet to be defined, and almost anything could happen.

travelling as a third person could also be interesting, but that would mean you could observe yourself, and have an influence on past events with knowledge of the present/relative future. dangerous thing about this, though, is that your observer form is based entirely on what you were like then. so, if anything you do changes your environment, you could potentially change in ... unexpected ways. mental instability, memories, etc etc.

it is all a really confusing thing to think about, but can lead to some amusing discussions. especially if there is some form of social lubricant involved. (yes, yes, i do like having a few drinks)

The third person thing kind of sounds like this show Quantum Leap. The guy can't time travel as himself- he was to move from person to person, and must "make right what once went wrong." The original plan was to observe history as a hologram, as you mentioned, but things obviously went wrong.

I've always been a fan of alternate universes. So if another "mirror" universe existed that was like ours only at a different time in history, it won't exactly be time travel. Well, technically... but it's more interdimensional travel than time travel anyway.

[Yet One More Idiot]

The John Connor problem isn't necessarily a paradox, as far as I can see.....true time loops, after all, have no end OR BEGINNING. They can just simply exist, pre-made, attached to the timeline. It doesn't violate the Novikov self-consistency theorem whatsoever, to have a closed timelike curve such as the events in the Terminator film, happening.

Back to the Future, as you say, can easily be explained by Doc's unwillingness to change past events - he invented the time machine, after all, to observe the past in action, not meddle with it.

The minor example in The Big Bang Theory, the way I see it, can also be explained as logical. Assume a timeline where Sheldon said something that annoyed Leonard. Leonard then travels back in time 5 minutes and hits earlier Sheldon over the head, thereby stopping him from what he'd been about to say. However, there are now three people in the room - Leonard and past Sheldon, AND past Leonard. By going back, Leonard is no longer in the timeline that he had originally experienced at all (since he doesn't remember earlier seeing himself arrive from the future or anyone hitting Sheldon) - by arriving in the past, he creates a new timeline that branches off from the original at the moment of his arrival. The motivation to hit Sheldon therefore never vanishes.

A less pleasant side-effect of this theory would be that in this new timeline, there are now TWO Leonards, which would be very difficult to explain away to the authorities. And in the original timeline, Leonard went back in time and simply vanished - because he'd in fact created a new reality and trapped himself in it. This doesn't violate conservation of mass, because there are two Leonards in the new reality, and none in the original - still averaging to one Leonard per reality.

[EverPhoenix]

A less pleasant side-effect of this theory would be that in this new timeline, there are now TWO Leonards, which would be very difficult to explain away to the authorities. And in the original timeline, Leonard went back in time and simply vanished - because he'd in fact created a new reality and trapped himself in it. This doesn't violate conservation of mass, because there are two Leonards in the new reality, and none in the original - still averaging to one Leonard per reality.

that depends on whether that time machine moves the driver in third person (as an observer), or whether it reverts them to how they were at the chosen time. the former is logically sound, the latter is where things get confusing.

[psychokind]

wasn't there something with past, present and future all going on simultaneously? kyle reese travels back to make his son, the future can't exist without the past being visited by the future, the present can't go on if the future didn't assure its existence by making sure that in the past the pasts present makes way for their future by making john connor?

[SoulBlazerFan]

wasn't there something with past, present and future all going on simultaneously? kyle reese travels back to make his son, the future can't exist without the past being visited by the future, the present can't go on if the future didn't assure its existence by making sure that in the past the pasts present makes way for their future by making john connor?

Well, think about this for a minute. There had to be a time when there was no machines in the past. Judgment Day happens with no pre-knowledge of that future. So, in the present, another man has to be John Conners father in order for that future to exist. It's after this timeline, as I said before, John Conner A sends Kyle Reese back because of the time displacement of First T-800 that was sent back to 1984.

In this timeline, Kyle Reese becomes father of John Conner B, who may or may not be identical to the original John Conner of timeline A. So this John Conner would have complete knowledge of the past, the future, of who Kyle Reese would be. This timeline would then be a complete loop, going on forever and ever.

[psychokind]

wasn't there something with past, present and future all going on simultaneously? kyle reese travels back to make his son, the future can't exist without the past being visited by the future, the present can't go on if the future didn't assure its existence by making sure that in the past the pasts present makes way for their future by making john connor?

Well, think about this for a minute. There had to be a time when there was no machines in the past. Judgment Day happens with no pre-knowledge of that future. So, in the present, another man has to be John Conners father in order for that future to exist. It's after this timeline, as I said before, John Conner A sends Kyle Reese back because of the time displacement of First T-800 that was sent back to 1984.

In this timeline, Kyle Reese becomes father of John Conner B, who may or may not be identical to the original John Conner of timeline A. So this John Conner would have complete knowledge of the past, the future, of who Kyle Reese would be. This timeline would then be a complete loop, going on forever and ever.

I know what you mean, but as we can see in Terminator 4, there is no way the judgement day can be prevailed, and the judgement day happens because of all the people/machines who come to the past.
future john connor knows about this and sends back all the guys to the past anyway.

this would mean the future and past exist parallel to each other. while people from the future come to the past, everything is already set and is part of the past. nobody in the future can do something to alter his current present.

[SoulBlazerFan]

wasn't there something with past, present and future all going on simultaneously? kyle reese travels back to make his son, the future can't exist without the past being visited by the future, the present can't go on if the future didn't assure its existence by making sure that in the past the pasts present makes way for their future by making john connor?

Well, think about this for a minute. There had to be a time when there was no machines in the past. Judgment Day happens with no pre-knowledge of that future. So, in the present, another man has to be John Conners father in order for that future to exist. It's after this timeline, as I said before, John Conner A sends Kyle Reese back because of the time displacement of First T-800 that was sent back to 1984.

In this timeline, Kyle Reese becomes father of John Conner B, who may or may not be identical to the original John Conner of timeline A. So this John Conner would have complete knowledge of the past, the future, of who Kyle Reese would be. This timeline would then be a complete loop, going on forever and ever.

I know what you mean, but as we can see in Terminator 4, there is no way the judgement day can be prevailed, and the judgement day happens because of all the people/machines who come to the past.
future john connor knows about this and sends back all the guys to the past anyway.

this would mean the future and past exist parallel to each other. while people from the future come to the past, everything is already set and is part of the past. nobody in the future can do something to alter his current present.

Then that would entirely negate the line, "There is no fate but what we make for ourselves." If what you say is true, then no matter what, John Conner cannot die. In more realistic terms, someone could go back, put a gun to Conners head- and he would not die, due to the fact that fate is inevitable. Thus, fate and destiny would be proved, and there is no way to alter the past.

I still think there had to be a "first" timeline.

I'm drawing up a diagram to show this point.

[inferiare]

Time travel can theoretically be possible. It's been theorized that if you were to get yourself directly into the middle of a black hole traveling at the speed of light you may be able to traverse time.

[NoZKeY]

Time travel can theoretically be possible. It's been theorized that if you were to get yourself directly into the middle of a black hole traveling at the speed of light you may be able to traverse time.

I think you don't need to get into a black hole. You just need to travel at a speed close to the speed of light.

[SoulBlazerFan]

Time travel can theoretically be possible. It's been theorized that if you were to get yourself directly into the middle of a black hole traveling at the speed of light you may be able to traverse time.

I think you don't need to get into a black hole. You just need to travel at a speed close to the speed of light.

That's not actual "time travel." If you move at the speed of light, time would literally stop all around you- when you slowed to a normal speed, you would actually be older than anyone else around you... or is it the other way around? I can't remember.

[EverPhoenix]

i think it is possible to time travel, assuming you can either exceed the speed of light, or travel at universally negative velocity. after that, the time dilation formula does funny things.