"Time Travel"

[devonin]

Re: "Time Travel"

If you go at high velocities, time passes more slowly for you. Why then would you expect backward time travel to affect THE ENTIRE UNIVERSE

It was inherant in the nature of time travel as discussed in this thread, that you were being picked up and moved backwards in time from when you started, and deposited into the same world earlier in time. It still only effects you, not the entire universe, you singularly were moved to an earlier point along the spatial dimension that time is. The issue is then one of whether what you can do while there will have any effect on the rest of the timeline, and people propose all kinds of paradoxes involving killing your grandfather, or whatever to somehow suggest that time travel would either be impossible, or destroy the universe.

Because if the time we have now is the result of the time line correcting itself on every backward time travel, THERE WOULD BE TIME PARADOXES.

I don't think there would be. Remember, what we perceive as reality is, in my theory, already effected by any and all actions that took place "in the past" whether those actions were carried out by people native to that fiction, or people from the future of that fiction.

It isn't a matter of saying "What happens if in 100 years, someone developes time travel and tries to go back in time to prevent Hitler coming to power?" because the fact that Hitler -did- come to power already shows that nobody did such a thing.

Whether that's because time travel included some means of guarenteeing that time travellers couldn't interfere in any way, or whether there's a group from further uptime whose job is to fix things people screw up, or because someone in the future went back in time to stop Gordon Jones from coming to power, and as a result of that prevention, allowed Hitler to come to power instead is irellevant, because whichever of those things might have been true, the end result was OUR PAST AS WE RECORDED IT.

Were someone -ever- to go back in time to try and prevent Hitler coming to power, they clearly either changed their mind, were stopped, or failed in their attempt, because he did come to power.

There are no paradoxes, because the past is already fixed, it is static and objective AND INCLUDES ALL MESSING AROUND DONE BY TIME TRAVELLERS.

[footbull3196]

Re: "Time Travel"

Actually, time travel is possible.

BUT, it's so improbable that it will almost likely never happen.

Also, if you went back and, let's say, killed your grandfather, a new parallel timeline would be created where you are not born. I'm not exactly sure how that would end up, but it's still interesting.

[devonin]

Re: "Time Travel"

Actually, time travel is possible.

BUT, it's so improbable that it will almost likely never happen.

Don't use absolute claims unless you can actually prove them. Please prove that your claim "Time Travel IS possible" is correct.

Also, if you went back and, let's say, killed your grandfather, a new parallel timeline would be created where you are not born. I'm not exactly sure how that would end up, but it's still interesting.

I would instead suggest that the fact that you are alive clearly shows that either you never went back in time to try and kill your grandfather, or that you failed in your attempt to do so.

Which seems like the more likely explanation of your existance?

"I went back in time, and killed my grandfather, which to avoid a paradox, created AN ENTIRELY SEPARATE UNIVERSE in which I wasn't born, for the SOLE REASON of avoiding a potential paradox involving my not being alive in order to go back in time"

or

"Because I do exist, I either never attempted to kill my grandfather in the first place, or I tried and failed"

[Afrobean]

Re: "Time Travel"

Don't use absolute claims unless you can actually prove them. Please prove that your claim "Time Travel IS possible" is correct.

We're traveling through time right now naturally. We know that time dilation occurs at high velocities and that gives us a means to control time's flow to a degree.

The only thing we don't have an absolute theoretical mechanism for is backwards time travel.

I would instead suggest that the fact that you are alive clearly shows that either you never went back in time to try and kill your grandfather, or that you failed in your attempt to do so.

No... you're misunderstanding the concept of a branched time line. There would be two points in time and space, simultaneously existing at different places in the 5th dimension. One would be the time where your grandfather is alive and you are alive, and your future self makes a trip to the past. The other would be an iteration of reality where you seemed to have come out of nowhere, killed who would have been your grandfather, and the you that should have been born according to your native timeline would never have been created.

These potential time lines are all existing within the 5th dimension and it's just our path along the 5th dimension that defines what form our 4th dimension takes.

Which seems like the more likely explanation of your existance?

"I went back in time, and killed my grandfather, which to avoid a paradox, created AN ENTIRELY SEPARATE UNIVERSE in which I wasn't born, for the SOLE REASON of avoiding a potential paradox involving my not being alive in order to go back in time"

or

"Because I do exist, I either never attempted to kill my grandfather in the first place, or I tried and failed"

If you take backward time travel as a given, you cannot very well say "I either never attempted to kill my grandfather... or I tried and failed." There are very basic tests to try to create this sort of paradox which should be fail-proof. Again, I would say that the only way that the Universe would "know" how to prevent such a paradox would be if there was an all-powerful, all-knowing god of time.

And again, you are misunderstanding the concept of branched time lines. The time that you "created" actually already existed in one form in the 5th dimension and our actions through the 4th dimension just never caused it to come into being in our dimension. However, going back in time and causing a shift in the events of the past would cause the time line to shift in another direction. And even though the time line that we see as established time would have shifted to another place in the 5th dimension, our previous 4th dimensional reality would still exist at another point within the 5th. In truth, the only one who would be aware of the change would be the time traveller, who will be composed of matter from a different place in the 3rd, 4th, and 5th dimensions.

But really, the paradox is explained perfectly on a branched time line. You killed someone who was your grandfather, but in killing him, all you did was put that time line on alternate path in which you don't exist. The paradox is irrelevant here, because the you that killed your grandfather is known to have time traveled to that time from a time and place where that man would have been your grandfather. Think of it this way:

Your home is at a coordinate in reality which can be defined by a set of 5 dimensions, which for the sake of argument I'll call (0, 0, 0, 0, 0). Now, the point in reality where your grandfather was killed by a time traveler from what is for them an alternate future can be defined as, let's say (-1, -1, -1, -1, 1). All you're doing is moving from one point in reality to another point in reality. There is no wave of refreshing on the time line that makes the paradox destroy the Universe; this is not Back to the Future. And if there was a wave that refreshed the timeline, how long would that take? What would trigger it? Why do you believe the Universe KNOWINGLY avoiding a time paradox makes more sense than explaining that the person who killed the man who would have been a grandfather was a person from an alternate reality in the 5th dimension?

Have you seen Sliders? You know how they go to other worlds and things? I believe in most of the worlds they went to, that world's copies of them were ALSO traveling through worlds, but sometimes they weren't. What they were doing is foregoing time travel and just hopping into the same point in time and space at different points in the 5th dimension. Would you consider their existence and affecting those "alternate" time lines to be paradoxical?

[devonin]

Re: "Time Travel"

You could try not just reexplaining your point as though I fail to understand it, because I clearly do understand it. Instead, I was showing a way in which you can resolve the idea of a time paradox without having to presuppose the existance of multiple universes.

Nowhere in anything I said, did I even imply that the universe is in any way self-correcting, that the universe "knows" anything.

What I said was "The fact that you exist shows that you did not kill your grandfather"

There are very basic tests to try to create this sort of paradox which should be fail-proof.

Such as? You're intending to just describe some set of circumstances where if you were hell-bent on creating a paradox you could simply arrange your attempt in such a way as to make it "impossible" to fail?

[Afrobean]

Re: "Time Travel"

Nowhere in anything I said, did I even imply that the universe is in any way self-correcting, that the universe "knows" anything.

If backwards time travel is possible (and traveling back in time can affect the "present" form of the person traveling through time, i.e., the time line refreshes itself when changed in the past) and it is still impossible to create a time paradox, that means that some sort of intelligence must be blocking it from happening before it can even occur. A time police system appears to be somewhat reasonable, but the refreshing nature and the paradox would still show through and by the time a time police force would be aware of an emerged time paradox, it would have already become apparent, turning causality on its head.

What I said was "The fact that you exist shows that you did not kill your grandfather"

And what I said was that your grandfather could simultaneously both live out his life or die in his youth by his potential grandson's hands. Schroedinger ****, I'll admit, but that is the view that I have on reality and the nature of higher dimensions. Do you not buy into the idea of multiple iterations of reality existing simultaneously in higher dimensions?

Such as? You're intending to just describe some set of circumstances where if you were hell-bent on creating a paradox you could simply arrange your attempt in such a way as to make it "impossible" to fail?

Uh, yeah. Like, go back in time one minute and shoot yourself in the head. The only way something simple as that could fail is:

#1: time travel skews into an alternate time line that exists simultaneously in another dimension
#2: backward time travel is not possible
#3: random chance
#4: some sort of intelligent and all-knowing/all-powerful being taking care to ensure that the attempt fails

The first example is what I think is right. The second is also a reasonable explanation. The third is essentially impossible, because even if the first attempt fails, given a potentially infinite number of attempts to create a paradox, there is no way, for example, that your gun would jam every time you try to kill your past self. The fourth jumps into the same area as intelligent design and there is no evidence to suggest that backward time travel has ever occurred in this iteration of reality, and if there were such evidence, an intelligent presence acting, even indirectly, would leave something to suggest that things we're playing out entirely on their own (for example, a person's gun jamming EVERY time they try to shoot their past self in the head would indicate something fishy).

[devonin]

Re: "Time Travel"

that means that some sort of intelligence must be blocking it from happening before it can even occur.

Why? You're leaping to a "necessary" conclusion that I don't feel is necessary at all. I didn't say something -blocks- a paradox from happening, I said that the fact of the state of reality just happens to show that you didn't succeed.

Team A winning the championship shows that team B failed to win the championship without some outside force necessary having -stopped- Team B from winning. You can still observe the lack of championship trophy in the possession of Team B and conclude "They failed to win the championship"

you can even exhaust a huge number of individual reasons why in any given case of the above, team B failed to win. Maybe a player got injured, maybe the referee got bribed, maybe the team simply played poorly, and on and on and on. By the same token, you seem insistant that there has to be ONLY ONE reason why time paradoxes don't happen. You're simply going from "I could resolve to engage in some paradoxical act involving time travel" and then leaping directly to "It succeeded with no problems, what are the consequences" without considering the myriad reasons that could each individually be why each individual attempt has apparantly failed.

Uh, yeah. Like, go back in time one minute and shoot yourself in the head. The only way something simple as that could fail is:

You're missing my point once again. I know what happened one minute ago, and it wasn't "A duplicate me appeared and shot me in the head" My point is thus: THE REASON WHY THAT IS THE CASE IS COMPLETELY AND UTTERLY IRELLEVANT TO ANYTHING.

The simple, observable fact of the matter is "One minute ago, I was not shot in the head" This is just the state of things. My chosen method to explain why "I did not shoot myself in the head one minute ago" is true is "Because I did not shoot myself in the head one minute ago."

You can try to call that tautological of you like, but it really isn't. As I mentioned before: For the same reason why the factual state of whether free will or determinism is true is irellevant (because we have either free will or a perfect illusion of free will) so too the case-by-case individual reason why time paradoxes haven't ever occured is irellevant.

It seems like you're assuming it goes "If someone were to go back from what is currently our future, to our objective past, and change something, effects would cascade forward, changing reality and potentially leading to paradox" And you choose to resolve those potential paradoxes by supposing that there must be alternate timelines causally seperated from this one which are the true destination for time travellers (Which to me, would make me say that they aren't actually time travellers)

Instead I'm saying "Any and all time travel that will ever occur in what is currently our future, to our objective past, has ALREADY HAPPENED AND LED TO OUR CURRENT REALITY"

Functionally, you left off #5: Reality as we percieve it is already the result of all time travel that will ever occur to a time before ours

[Afrobean]

Re: "Time Travel"

Why? You're leaping to a "necessary" conclusion that I don't feel is necessary at all. I didn't say something -blocks- a paradox from happening, I said that the fact of the state of reality just happens to show that you didn't succeed.

But in the case of history-altering paradoxes, it simply just "not happening" doesn't mean anything. Yes, I have never gone back in time and killed my past self (as per this iteration of reality anyway), but that does not mean that if I did attempt it, it would fail.

You're arguing that time paradoxes wouldn't be possible because history says that they haven't. However, this isn't a legitimate argument to make, because history also says that no one has ever traveled back in time, nor has anyone ever attempted to create a paradox.

In addition, I might add that ANY trip to the past where the intention is to change the past in ANY way would create a time paradox. In addition, the butterfly effect can cause unintended changes which could trigger time paradoxes by mere observation of the past.

Team A winning the championship shows that team B failed to win the championship without some outside force necessary having -stopped- Team B from winning. You can still observe the lack of championship trophy in the possession of Team B and conclude "They failed to win the championship"

This is time travel, buddy. Pure theory. You cannot draw parallels to established existence when we can't even say with certainty that backward time travel is even physically possible.

you can even exhaust a huge number of individual reasons why in any given case of the above, team B failed to win. Maybe a player got injured, maybe the referee got bribed, maybe the team simply played poorly, and on and on and on. By the same token, you seem insistant that there has to be ONLY ONE reason why time paradoxes don't happen. You're simply going from "I could resolve to engage in some paradoxical act involving time travel" and then leaping directly to "It succeeded with no problems, what are the consequences" without considering the myriad reasons that could each individually be why each individual attempt has apparantly failed.

Ok, given the situation that time travel is possible and I have a time machine, and Back to the Future rules of the flow of time apply:

I go back in time 1 minute to kill my past self. However, my future self's existence means that I must have failed in my past attempt to kill my past self, according to your "only one iteration of time that encompasses all future travels to the past". However, I wouldn't even have a memory of my future self having tried to kill me. And how would I fail? My gun would jam? My shot would miss? What happens when I try over and over? First attempt fails? Go back in time again and attempt a second try while my first try is busy failing. Second try fails? Go back in time again.

You're basically saying that I could try millions of times to kill myself in that instance, with millions of time doppelganger copies of myself attempt to kill the original. And all of the millions of the attempts would fail.

You're missing my point once again. I know what happened one minute ago, and it wasn't "A duplicate me appeared and shot me in the head" My point is thus: THE REASON WHY THAT IS THE CASE IS COMPLETELY AND UTTERLY IRELLEVANT TO ANYTHING.

What of a sniper shot? What about other ways in which one can affect time to cause a paradox without the past persons being aware of a future person's presence?

Anyway, you actually seem to be arguing that traveling back in time isn't even possible in your "yeah but then I would remember it" idea. History has no indication of a person traveling through time, so no, we don't remember it.

The simple, observable fact of the matter is "One minute ago, I was not shot in the head" This is just the state of things. My chosen method to explain why "I did not shoot myself in the head one minute ago" is true is "Because I did not shoot myself in the head one minute ago."

You cannot use the basic fundamentals of causality to explain a time paradox. Doing so in your manner indicates that backwards time travel is not even possible, and if you're going to take that stance, is discussion of the topic even worth putting forth?

The very reason that time paradoxes are worth thinking about and discussing is BECAUSE they throw causality into question.

It seems like you're assuming it goes "If someone were to go back from what is currently our future, to our objective past, and change something, effects would cascade forward, changing reality and potentially leading to paradox" And you choose to resolve those potential paradoxes by supposing that there must be alternate timelines causally seperated from this one which are the true destination for time travellers (Which to me, would make me say that they aren't actually time travellers)

Yeah, that's right.

Also notice that I never indicated that someone remaining in the same time and space, but moving across to an alternate time line (i.e. 5th dimension, ala Sliders), were time travelers.

And yes, if it is possible to travel back in time, and the future is not set in stone, and there is only one iteration of time that contains all time travels already, future trips to the past would have to cause a "cascading effect". This is how Back to the Future works, and this is why time paradoxes can cause a problem for this model of time travel.

Instead I'm saying "Any and all time travel that will ever occur in what is currently our future, to our objective past, has ALREADY HAPPENED AND LED TO OUR CURRENT REALITY"

Talking like that is the same as saying "traveling into the past that has already happened is not possible".

Functionally, you left off #5: Reality as we percieve it is already the result of all time travel that will ever occur to a time before ours

I left that out because it is related to the second conclusion: that time travel into the past is not possible. Yes, reality as we know it does contain all trips to the past thus far: ZERO.

[devonin]

Re: "Time Travel"

You're arguing that time paradoxes wouldn't be possible because history says that they haven't. However, this isn't a legitimate argument to make, because history also says that no one has ever traveled back in time, nor has anyone ever attempted to create a paradox.

History doesn't say anybody has travelled back in time because we haven't invented time travel yet. History -has- recorded a number of people who claim to be from the future, but obviously, there is some difficulty in proving that. I think what you wanted to say was 'History shows no evidence of meddling by time travellers' to which I say "Of course not, because history is the result of that meddling."

but that does not mean that if I did attempt it, it would fail.

I didn't say if you did attempt it, you would fail. I said that it didn't happen. I made no claims whatsoever as to the reasons why it didn't happen.

However, I wouldn't even have a memory of my future self having tried to kill me. And how would I fail? My gun would jam? My shot would miss? What happens when I try over and over? First attempt fails? Go back in time again and attempt a second try while my first try is busy failing. Second try fails? Go back in time again.

Think back one minute ago. Did a duplicate of you appear and try to kill you? No? Then you didn't go back in time from one minute from now and try to kill yourself. Whether you have a time machine, or Back to the Future rules apply, there is only one instance of each time-slice in the past, if it will have included time travellers in that time-slice, it already includes those time travellers.

No future you trying to kill you one minute ago? Then one minute-from-now-you doesn't make the attempt, or is stopped in the attempt in some fashion. Since I can't see into the future, I have no way to know which mechanism stopped you, but one hopes "Good sense and a desire to not create a paradox" featured highly in the reasoning.

History has no indication of a person traveling through time, so no, we don't remember it.

History has no indication of what I ate for breakfast on September 2nd 1990, unless someone happens to remember for some reason (I dont' remember) that doesn't mean I didn't eat breakfast on September 2nd 1990. There are all kinds of historical accounts of things that -could- be interpreted as evidence of time travellers, but what are you looking for? Something in the writings of Aristotle about travellers from the future? A newspaper article "Men from the future captured in Nazi Germany!"

I said that our reality is already the result of any meddling that has or will have happened due to people travelling into the past. I don't see why there MUST be some sort of recorded evidence that these people were there, presumably if they went back in time they were clever enough to at least blend in.

And yes, if it is possible to travel back in time, and the future is not set in stone, and there is only one iteration of time that contains all time travels already, future trips to the past would have to cause a "cascading effect". This is how Back to the Future works, and this is why time paradoxes can cause a problem for this model of time travel.

Let's try again: The cascade has already happened. We are already living the results of meddling with the past. There will be no sudden "new" cascade, because even if in 1,000,000 years, someone goes back to 1980 to screw with time, 1980 already happened, thus their visit already happened, thus any changes to the timeline already happened, leaving us with this one. Because that cascade happened, whatever the results of the cascade were, they did not include anything that would have led to the traveller not being alive to make the trip, because they did make the trip.

Talking like that is the same as saying "traveling into the past that has already happened is not possible".

I disagree, considering my statement explicity assumes that time travel -is- possible.

Yes, reality as we know it does contain all trips to the past thus far: ZERO.

And it contains all trips to the past that haven't happened yet: SOME NUMBER WE CANNOT RELIABLY ASSUME

[Afrobean]

Re: "Time Travel"

dev...



All I'm hearing from you is "time travel into the past must not be possible."

So quick question. We take the assumption that backward time travel is possible, right? But the future is not set in stone? How is it then that the time travels from the future exist in the "stone" past if the future is not yet set?

Your whole argument is hinged on the fact that no one has actually traveled through time to the past and that no one has ever done so with a purpose that would cause a paradox. It doesn't even have to be something as absurd as killing your past self or killing your grandfather. Say you intended to go back in time to stop a terrible dictator from coming to power. The only way that such a trip could have NOT created a paradox is if the attempt to stop him failed. But then, if the people of the future are familiar with time travel and know the past is set in stone, couldn't the potential time traveler look at the past and notice that their attempt in the past didn't succeed and thus, never bother going back there in the first place, thus bringing about a completely different paradox?

Your model of time travel does not negate the possibility of paradoxes and it does not even come close to answering the questions presented by them. You're basically saying "no one's traveled through time, so no one created a paradox," then from there, you're taking the point that "no one has created a paradox" and saying that's because they haven't tried (or that they've all MIRACULOUSLY failed); you're making an assumption that is only possible as a good conclusion if you take the stance that time travel to the past is not possible.

And bro, let me tell you, if backwards time travel ever becomes possible, paradoxes are inevitable. The very nature of traveling back in time removes causality from the equation. Everything in the world follows the basic rules of cause and effect. But when someone appears from the future, there is an effect of additional matter and energy entering the 3rd dimension of the Universe without a cause-effect relationship in the 4th dimension.

Even if you go back in time only to observe and do not truly affect anything, butterfly effect can take hold and **** everything up just because of a few misplaced air molecules.

ps

And it contains all trips to the past that haven't happened yet: SOME NUMBER WE CANNOT RELIABLY ASSUME

Then why do you feel your conclusion is reliable to assume? You don't know how many trips might have happened in the future, why then do you feel it is reasonable to draw the conclusion that our past is riddled with the people of the future mucking about in it? There is no good evidence suggesting that someone from the future has ever mucked about in our past, so why would you come to that conclusion?

Really, man, you're making the assumption that people of the future would be noble and not **** with time, but do you really think that they would? Time travelers first steps would be to scientifically measure how they can affect the past, then, if it is safe, they'd go back and push humanity forward earlier on. They'd go back and erase the dark ages, push back the technological age a couple hundred or thousand years. They'd use their power to advance humanity in ways never before thought possible.

[devonin]

Re: "Time Travel"

I cannot conceive of a group of people "Noble enough to want to help humanity" via time travel who woudln't also be noble enough and intelligent enough to know that the potential risks are not worth it.

Again, since time travel does not currently exist, we really have no basis to assume that were it to be developed at some point in the future, that it would be in any way shape or form commonly accessible to whoever happens to want to use it.

I can't think of a thing which would be -more- prone to being regulated, controlled and monitored than the potentiality of backwards time travel. You're assuming just as many things about how time travel would work as you negatively accuse me of doing.

What's your basis for the assumption that time travel to the past needs to include the addition of matter and energy into the universe? Could time travel not potentially be developed in such a way as to render the traveller bound by "You can look but you cannot touch" not in the sense of "don't" but in the sense of "Is completely unable to"

If we're assuming that the universe has to follow its various laws that seem pretty much objectively true, why couldn't potential travellers be "out of phase" with reality as we understand it, able to move about and observe, but not actually able to effect anything by their presence? There's a potential version of time travel that is paradox free.

The main issue here is that you're saying "If we assume that someone travelling back in time must effect the timeline with consequences cascading" but even with my concept that time travel doesn't also include parallel universe travel, one of the potential explanations for the lack of paradoxes can easily be "Because travellers to the past can't actually interact with anything."

As I said more than once, the individual reasons why time travel in each instance of time travel hasn't led to a paradox don't especially matter, but I don't even mean they don't MATTER, so much as the fact that they are currently UNKNOWABLE so Agnostics ahoy, trying to imagine now whether it's time police, or failed attempts, or whatever doesn't actually DO anything. The lack of paradoxes shows that there is a lack of paradoxes.

Basically you're saying something like "You say that nobody has successfully carried out a paradoxical action while time travelling, but since -I- think that paradoxical actions are inevitable, the only way I can possibly accept your premise is if I assume that your conclusion is 'time travel is impossible'"

But since my conclusion is not "Time travel is impossible" but instead "Whether time travel is possible or not, nobody who has travelled to a time before right now has ever done anything paradoxical FOR WHATEVER REASON" So again, second thoughts, failed attempts, time police, time travel putting you out of phase, whatever the individual reasons happen to be, the evidence seems clear to me (Namely, that the universe hasn't exploded in a puff of logic) that whether you CAN create a paradox or not, no paradox has taken place before january 19th 2009 at whatever time you happen to see this.

[footbull3196]

Re: "Time Travel"

Don't use absolute claims unless you can actually prove them. Please prove that your claim "Time Travel IS possible" is correct.

Ok, well, I wasn't able to prove it yesterday since I somehow got banned, but anyways, there's this series called "Time" or whatever on the Science Channel with some Asian guy, and that's what they said on that show.

They also did some test with time. They took some thing that flashed numbers really quickly. Then they made a simulation to see if time slowed down during a near death experience. They took some guy up to the top of some tower and dropped him 100+ feet into a net. Not really a near-death experience, but he was stlil able to see the numbers.

Anyways, I thought that was cool, and on that show, they did say that time travel was possible, but just infinitely improbable. The odds of getting it right are like slim to none.

[zhul4nder]

Re: "Time Travel"

The term is sometimes used in popular media dealing with the idea of time travel, usually inaccurately. Most time travel depictions simply fail to address butterfly effects. According to the actual theory, if history could be "changed" at all (so that one is not invoking something like the Novikov self-consistency principle which would ensure a fixed self-consistent timeline), the mere presence of the time travelers in the past would be enough to change short-term events (such as the weather) and would also have an unpredictable impact on the distant future. Therefore, no one who travels into the past could ever return to the same version of reality he or she had come from and could have therefore not been able to travel back in time in the first place, which would create a phenomenon known as a time paradox.


-wiki owns you. Time travel is impossible because there would be no time to come back to.

[devonin]

Re: "Time Travel"

Footbull: "I saw it on TV one time" does not constitute proof, I'm pretty sure I've said as much to you once already. Also, none of your examples has the first thing to do with time travel. They have to do with testing the objective accuracy of subjective time dialation. Unfortunately for you, actual time dialation absolutely occurs and has been proven, involving very accurate clocks and very high speeds.

zhul4nder: They're just supposing that the mere presence of time travellers would change short term events, but even granting that, it in no way suggests that that butterfly effect would cause any kind of paradox, just that it would send a cascade of modified causes and effects moving forward. They could be very minor effects and still be effects. Also, just because the 'present' you returned to would not be the same as the one you left doesn't mean time travel is impossible, it just means time travel has consequences, which nobody here has been denying. Moreover, wiki owns nothing in this forum. Wiki's no more legitimate a source than anything else we're referencing or drawing from.

[Afrobean]

Re: "Time Travel"

I cannot conceive of a group of people "Noble enough to want to help humanity" via time travel who woudln't also be noble enough and intelligent enough to know that the potential risks are not worth it.

Like I said, ANY trip to the past could potentially cause a paradox, even if they do not intend to do anything.

And come on, you know scientists would be all over experiments involving time travel if they figured out how to do it.

Again, since time travel does not currently exist, we really have no basis to assume that were it to be developed at some point in the future, that it would be in any way shape or form commonly accessible to whoever happens to want to use it.

If ANYONE used it, it could cause a paradox.

And again, scientists would having nerdgasms all day long about experimenting with time travel.

I can't think of a thing which would be -more- prone to being regulated, controlled and monitored than the potentiality of backwards time travel. You're assuming just as many things about how time travel would work as you negatively accuse me of doing.

The only assumption I am making is that scientists would experiment with time travel if given the opportunity.

Do you disagree?

What's your basis for the assumption that time travel to the past needs to include the addition of matter and energy into the universe? Could time travel not potentially be developed in such a way as to render the traveller bound by "You can look but you cannot touch" not in the sense of "don't" but in the sense of "Is completely unable to"

I thought about this and I decided that such a development would probably need to be artificially crafted.

Anyway, if they're able to go back and observe things, how would it be possible for them to not affect ANYTHING? Are you suggesting that a function of the Universe would be to stop them from being able to act? What about basic ideas of physics? If a time traveler punches a caveman in the face, what happens to the energy that should be imparted to the past-dweller's face?

If we're assuming that the universe has to follow its various laws that seem pretty much objectively true, why couldn't potential travellers be "out of phase" with reality as we understand it, able to move about and observe, but not actually able to effect anything by their presence? There's a potential version of time travel that is paradox free.

You mean, like floating out in the fifth dimension, looking at cross-sections of the 4th?

That wouldn't be time TRAVEL though. That would be like looking at a photograph; just seeing the photograph isn't the same as BEING there.

The main issue here is that you're saying "If we assume that someone travelling back in time must effect the timeline with consequences cascading" but even with my concept that time travel doesn't also include parallel universe travel, one of the potential explanations for the lack of paradoxes can easily be "Because travellers to the past can't actually interact with anything."

I don't think this is possible without an artificial construct, and frankly, I doubt if the scientists to discover and first experiment would go to such extreme lengths as developing a method whereby they can be present in a space without affecting any matter or energy around them and also be completely invisible.

I'd guess the only way to achieve that would be to bend space-time around them, but then again, if they did that, it wouldn't even be possible for them to observe anything anyway (light would bend like-wise around them as well).

As I said more than once, the individual reasons why time travel in each instance of time travel hasn't led to a paradox don't especially matter, but I don't even mean they don't MATTER, so much as the fact that they are currently UNKNOWABLE so Agnostics ahoy, trying to imagine now whether it's time police, or failed attempts, or whatever doesn't actually DO anything. The lack of paradoxes shows that there is a lack of paradoxes.

Right, but the lack of paradoxes does not indicate a lack OR presence of future travel to the past. Your argument does not imply your conclusion. Lack of paradoxes does truly indicate a lack of paradoxes, but it doesn't mean that all future time travel to our past is already present in our "stone" past.

Basically you're saying something like "You say that nobody has successfully carried out a paradoxical action while time travelling, but since -I- think that paradoxical actions are inevitable, the only way I can possibly accept your premise is if I assume that your conclusion is 'time travel is impossible'"

Yes. Any travel back in time is likely to cause a paradox, not necessarily by direct action (such as killing your past self), but by the butterfly effect.

But since my conclusion is not "Time travel is impossible" but instead "Whether time travel is possible or not, nobody who has travelled to a time before right now has ever done anything paradoxical FOR WHATEVER REASON" So again, second thoughts, failed attempts, time police, time travel putting you out of phase, whatever the individual reasons happen to be, the evidence seems clear to me (Namely, that the universe hasn't exploded in a puff of logic) that whether you CAN create a paradox or not, no paradox has taken place before january 19th 2009 at whatever time you happen to see this.

I agree that the Universe can't "explode in a puff of logic", but I agree with this because I believe the Universe would just derail onto a new track in the 5th dimension.

Quick question, dev. Assuming time travel is possible, do you think it could ever be possible to travel DIRECTLY to alternate time lines? For example, you don't think we can go back in time and change the past from what we know to be the past, but could we hop from this point in time in the 5th dimension to the same point in time at another point in the 5th dimension? For example, say I had a near death experience, but barely survived. Do you believe there could be another iteration of reality that physically viable in another form where I did die? If not, why not?

ps zhul4nder, right, but what about shorter trips? If I go back in time one hour (and don't do anything which would directly stop myself from making the same trip in an hour), do you really think the butterfly effect would cause such drastic effects? Yes, it would be a different "present" I'd be "returning" to, but it would be fundamentally the same and the changes could quite possibly be entirely unnoticeable.

edit:

Wiki's no more legitimate a source than anything else we're referencing or drawing from.

lolz

I'm drawing from scifi movies and TV shows 8)