Time loop and time paradox

[zman9000]

So I had this idea for another topic that will make you think.
So here is three different things to talk about.

#1
Recurring Stable Time loop: Basically take some action that creates a time loop, that loops a number of times with out causing a paradox that then continues along the normal flow of time.
[Note: it is possible]

#2
Time Paradox: Your thoughts on how a time paradox could be avoided once it has already occurred.
[Note: not sure if possible]

#3
Explain your own theory on how time really works. and how it would compensate for a paradox with out annihilating its self. (keep in mind that due to some experiments with the large hydron collider we can't say for sure travel back in time isn't possible.)
______________________________________________________________________
Those of you who know me, you know I love this kinda stuff, and have spent a great amount of time thinking about some of this stuff.
Leaf, Kain, and maybe Salanewt might remember awhile back I had posted a long rant on Skype relating to #1. and made a possible solution for this. And it even included a way that you would interact with your past self with out altering time in 100 recurring time loops that then continued along the normal flow of time with zero differences.

I'd re-post it here, but i don't feel like typing for 3 hours again, that and if i posted it there wouldn't really be anything to discuss about it.

[Daddy Poi's Oily Gorillas]

Number 2 reminds me of Family Guy. XD

Time is like a fourth dimension, right?

How about the speed of time? (Like when we age.) Imagine if you could watch life happen backwards.

Hmm... random thought. Where do you go if you enter a black hole? (And is time different when you do... etc.)

[leaf]

...oh my. I think this question is a bit advanced for this forum.

Anyway, #1 is analogous to Novikov's self-consistency principle.

#2 should theoretically be impossible. By definition, a paradox is a situation that should not be able to occur, because multiple contradicting states are being fulfilled at once. As such, any way to "avoid" a paradox would prevent the paradox from ever occurring in the first place.

For #3... I think there's a couple of equally likely scenarios:
1) Infinitely many worlds exist, each on their own separate time lines. Time in these worlds may or may not be equivalent. For example, a world in the "future" would have faster time than our world, and if you spend one hour in that world, it might be equivalent to only 55 minutes in the real world. While a world in the "past" would have slower time than our world, and spending one hour in that world would be equivalent to spending 65 minutes in ours. Since the worlds are infinite, there are an infinite number of time steps, as well as an infinite number of branching possibilities the worlds can follow. Of course, for time travel to work, the time steps don't have to be different. The mere fact that there are infinitely many worlds makes it possible to avoid paradoxes.
2) Only our world exists. In general, it wouldn't matter if this was true or not; with our current technology, we have no way of verifying this. However, as we have not yet had any documentation of beings crossing over to our world from another, we have nothing to disprove it, either. If only our world exists, time travel is likely impossible, or only possible by way of a stable time loop. Changing the past would be absolutely impossible.


@Teawater: Eh... just read the wiki article. http://en.wikipedia.org/wiki/Black_hole

[zman9000]

For #3 my own theory is this. there aren't multiple worlds, and you could go back in time and kill your self with no paradoxes.
you will be in the same world back in time, and you would have actually died. but there's nothing to say that once in the past you will go away if something happens to the other you. And that same matter in the same place at the same time bull @#$%, for one, its not like all matter has some bar-code that makes it different from every other piece of matter in existence.

Problem is people try to think from a moral standpoint, as if for some reason the universe was made to be perfect and fair. Like if there is only one world, what does that say about the people in the world that doesn't exist anymore?

think of it like this.
Time is relative. what has already happened can't be changed, but what has yet to happen can be changed completely.
you can't change the past from the present but but you can change the future from the present. so going back in time reverses what has happened and while back you can change what will happen.

[Zach]

Theory for #3: From what we know, time is infinite and everything has a cycle. Because there are cycles, time has a habit of repeating itself off and on again. With this in mind, I believe time is forever in a never-ending loop. With each second, you are simultaneously in the past, present, and future; during the second you are in the present and with each millisecond that passes you are in the past while stepping into the future. As for parallel universes, eh......if time travel were possible, then I could believe it. I would have to see it to believe it (although it would be somewhat kickass to time travel :D). With time travel, I believe that if we were able to time travel and went back in the past, we could change the future, however; the future would only be changed in the past that you visited and not the future that you were in. On the flipside, you very well would be able to alter the future that you came from by screwing with the past. Either way, we won't know till it happens and with our current technology, that won't happen in our lifetime UNLESS we do what they did in the Mass Effect trilogy and stumble upon alien/sophisticated technology on Mars or some other planet

[leaf]

For #3 my own theory is this. there aren't multiple worlds, and you could go back in time and kill your self with no paradoxes.
you will be in the same world back in time, and you would have actually died. but there's nothing to say that once in the past you will go away if something happens to the other you. And that same matter in the same place at the same time bull @#$%, for one, its not like all matter has some bar-code that makes it different from every other piece of matter in existence.

Problem is people try to think from a moral standpoint, as if for some reason the universe was made to be perfect and fair. Like if there is only one world, what does that say about the people in the world that doesn't exist anymore?

think of it like this.
Time is relative. what has already happened can't be changed, but what has yet to happen can be changed completely.
you can't change the past from the present but but you can change the future from the present. so going back in time reverses what has happened and while back you can change what will happen.

Actually, I would argue that you can't change anything and that everything is pre-determined, but that's another topic for another day.

Now zed, for your theory to be true, it would mean that you would be physically able to change the past. Your "present" is deconstructed the moment you leave it and replaced by one in which you travelled in time to the past. This results in the breakdown of causality, since "the creation of the time machine" itself becomes null. For all intents and purposes, a time machine and time traveller have just been "created" at the point in space-time that they land. Any future point beyond then is null and can be reshaped.

If we assume that the entire timeline between when a time machine is used and when it appears in the past "never happened" (which is what that theory would entail), then time does not need to flow continuously from point A to point B. Time jumps from point A to point B, and then jumps back to point A again. Time then begins to flow in a continuous stream once more, toward a new point B'.

What does all this mean? It means that if someone had ever or was ever going to travel into our "past," they would have already done so. By your theory, the moment time travel occurs, an entire timeline is instantaneously destroyed and is replaced by the new "proper" one. If someone were going to time travel into our past and had not yet done so, we would be unable to talk about this right now, since we wouldn't exist. Therefore, if there has not yet been any time travel to a point in our past, there never will be one, and if there has been one or more, there will never be any more.

But, there can be time travellers who arrive in our "future." That is still a possibility. As it has not happened yet, we would not know if the future was being reconstructed, or if there were sudden "jumps" in time. And if it ever does happen, you would not be able to tell the difference. The effective result would be that a new mass is "created" in our world, claiming to be from the "future." And that is all that would happen.

Now, certainly, when you look at time travel like this, it presents tons of inconsistencies. First off, energy/matter can not be created or destroyed, so this violates the second law of thermodynamics. Second, where would this person come from? Their future never existed, so how can they be here? Third, this is a HIGHLY self-referential theory. It's reminiscent of the ancient greeks thinking that the sun revolves around the earth, rather than the other way around. This theory is rooted in the belief that we are on the one and only correct timeline, and that time is (mostly) linear. I find these to be extremely foolish assumptions, especially the latter; if we're talking about time travel, then time cannot be linear.

In order to maintain causality, the only possibilities for time travel are one of the following:
1) A stable time loop: At some point in the past, something happened, which gives the traveller a reason to want to travel back in time to stop it from happening (or to make something happen that didn't happen). The time traveller returns to the past, and whatever had happened originally happens anyway, in the exact same way it happened the first time. It's possible that it could happen because of their interference, but that presents its own set of problems.
2) Multiple worlds: I find this to be the most realistic of the time travel theories. Or rather, the most realistic of the ones that allow for "alteration of the past." It works similarly to the "linear" theory you mentioned, but bypasses the main problems of it by actually giving the time traveller a source world. It is, however, bound by the same limitation - it is impossible for a time traveller to arrive in our "past." A different world may be in a state that is identical to a point in our "past," but it is still its own world with its own conditions; the fact that those conditions exactly match a point in our past is just coincidence. Therefore, a "time traveller" could only subjectively change the "present." As far as the time traveller is concerned, they have "altered the past." However, to those in the time traveller's home world, no change is observed, except for the disappearance of the time traveller to another world at the point they left in the time machine. Additionally, to the people in the world that the time traveller arrived in, the time traveller has "altered the present" or "altered the future," but the time traveller distinctly never changes the "past." As a result, perhaps "world hopper" would be a more accurate term here than "time traveller."

Problem is people try to think from a moral standpoint, as if for some reason the universe was made to be perfect and fair. Like if there is only one world, what does that say about the people in the world that doesn't exist anymore?

Where did this bullshit come from? No one thinks the world is perfect or fair. However, we do expect it to behave in a logical and consistent manner. If the world was going to be destroyed at some point in the past and reconstructed, it should have already done so, otherwise we could never have existed to have this conversation.

[zman9000]

a few things with your theory, that, I'm not sure how to explain but i think are off a little.

first off

First off, energy/matter can not be created or destroyed, so this violates the second law of thermodynamics.

except for the disappearance of the time traveller to another world at the point they left in the time machine.

... wouldn't this technically... well what ever...

also there's something you used as an argument that made me remember something I read on some of the tests done with the large hydron collider.
[spoiler]something about the universe being chaotic and doesn't follow logic. They tested some particle's and found that under the same test with everything exactly the same, they got different results every time. And there was something about the discovery that at a certain point matter transfers in and out of existence but the mass of the universe always stays the same... [/spoiler]
(don't quote for details)

And everything you have said doesn't mean my theory is impossible nor does it make it very unlikely its how it actually works, since we can't explain how matter exists.
Now My point is lets say time exists in a straight like, and it is well known that a person is the what their memory's and experiences make them.
by that, it would mean, everything you do, think, and do after reading this was bound to happen.
But going back in time you say it destroys the future you come from. but for the people of that time, it hasn't happened yet so nothing has been destroyed.
as for matter being created and destroyed, think of the game portal, going through the portal it doesn't destroy anything and then recreate it on the other side. both places are at the same place already. in this case, matter would be taken from the future and end up in the past. matter isn't linked to anything but its self, there suddenly being more energy in the universe isn't going to destroy it. In a sense the energy came from an existence that never existed.

Finally I have something else to think about. say time does move in a straight like, and the future were to open a portal to the past, that links the two times.
there aren't now two different worlds. they are one world, and should the portal close the other world would no longer exist to the other. I suppose this is kinda the multiple worlds theory, but both worlds exist, and don't exist at the same time. while connected, they are one, and when they separate, they are still only one.

So basically I'm saying there is only ever one world/dimension and when two times meet the merge, when they separate they no longer exist with in reality or time.
What I'm trying to describe has no words to explain it as its talking about some that exists and doesn't...
just because its something you can't ever hope comprehend doesn't mean it doesn't work that way. This only holds up if time is like a straight line.

should there be multiple universes you should be able to reconnect that portal where the past and future meet.

[leaf]

For the part you quoted, it's because it's holding the mass/energy of all worlds together as a constant. It depends on what you consider to be the system. While sure, if you only look a small segment of a river, mass is entering and leaving that system constantly. But if you look at the entirety of the whole universe, mass/energy do not enter or leave, and are neither created nor destroyed. So, if our world were only a subset within the universe, with many parallel worlds, in order to apply conservation laws, you would have to consider the system to encompass all of the parallel worlds. If only one world ever existed at a time and time travel were possible, it would be possible to "create" matter/energy, which is obviously a problem.

As for the stuff you referenced about particles taking on different states, that's only on the quantum level. Quantum interactions are influenced by the observer, which makes studying them extremely difficult. Despite having so many researchers working on it, there still is no complete theory of quantum mechanics. In other words, it's inappropriate to assume that there isn't a reason for the particles taking on different states each time. It's just that we haven't been able to isolate why.

as for matter being created and destroyed, think of the game portal, going through the portal it doesn't destroy anything and then recreate it on the other side. both places are at the same place already. in this case, matter would be taken from the future and end up in the past. matter isn't linked to anything but its self, there suddenly being more energy in the universe isn't going to destroy it. In a sense the energy came from an existence that never existed.

The problem isn't necessarily that energy or mass was added to the universe. Conservation laws are merely laws that explain what happens in reality. In that sense, conservation laws are not actually fundamental laws of the universe; causality is. As such, the real problem at hand is the breakdown of causality. Things do not just spontaneously appear in reality like that (at least not on the macro scale).

Finally I have something else to think about. say time does move in a straight like, and the future were to open a portal to the past, that links the two times.
there aren't now two different worlds. they are one world, and should the portal close the other world would no longer exist to the other. I suppose this is kinda the multiple worlds theory, but both worlds exist, and don't exist at the same time. while connected, they are one, and when they separate, they are still only one.

This is basically the first theory I mentioned, the stable time loop as specified by novikov's self-consistency principle. In this, all events are still preconfigured to happen. The oddity is that this allows for a reversal of causality: something happens in the past because of meddling from the future, but the meddling in the future is caused by the event happening in the past. The meddling in the past was set in stone as it already happened, but the cause is determined later, in the future. That's why I don't like it. While it doesn't cause world-shattering issues, it still breaks causality.

So basically I'm saying there is only ever one world/dimension and when two times meet the merge, when they separate they no longer exist with in reality or time.
What I'm trying to describe has no words to explain it as its talking about some that exists and doesn't...
just because its something you can't ever hope comprehend doesn't mean it doesn't work that way. This only holds up if time is like a straight line.

Uh... all I'm getting from this is you don't want to be wrong, so you're making @#$% up to make yourself sound philosophical.

[zman9000]

Uh... all I'm getting from this is you don't want to be wrong, so you're making @#$% up to make yourself sound philosophical.

nono, don't get me wrong, I remember something like this from some where. trying to describe something that doesn't exist means its something that can't be described because it exists out side of reality and doesn't follow any laws we can know.

its like saying, where does heaven exist if you are a christian. the simple way to think about it is its like a higher dimension that is completely different and can't even be described because you can't even comprehend it. And in a way, it doesn't exist yet it does.

I don't really remember all what i was getting at, but this is all such a complicated thing that we tend to go for whats most logical, assuming the universe is logical.

[leaf]

Remember that there's a difference between "logical" and "intuitive." Even if something may not intuitively "make sense," it's still possible for it to be "logical." However, if something does not follow logical rules, then it is entirely impossible to have any discussion on it whatsoever. If an entity violates logic, there is no cause and effect, and no way to verify validity of claims.

There is good reason people trend toward the simpler explanations. All other things being equal, the simpler solution is more often the correct one. While, sure, it's possible that crop circles appeared on a farmer's land because aliens from lightyears away visited earth and the only thing they did was leave behind an imprint in a field, the more likely explanation is the simpler one, that a person went out and flattened the crops during the night. The explanation that the universe does not follow defined rules is about as complex of an explanation as you can get, since you would need to explain away any emerging patterns as a "statistical improbability" or as an "insufficient quantity of data."

[Jiten]

I'd re-post it here, but i don't feel like typing for 3 hours again, that and if i posted it there wouldn't really be anything to discuss about it.

Why not just copy and paste it from the chat?

[zman9000]

Why not just copy and paste it from the chat?

sure, i'll just scroll back a little over half a year and find it...
ha-ha no! and besides, I'd like to see how some one else will tackle the problem.

well you know what... lets see how short i can make it...
[spoiler]it involves 2 different time jumps for each loop, one indirect meeting with your your self each loop, two rooms with a space in between you can pass things between with out seeing the other room, and a mechanical device of some kind like a candy dispenser.
the loop will go 100 times then complete its self.

first you start in one room, and look in the space between rooms, if its empty you travel back in time to a set place where the dispenser and use it.
you then take what you get and from the other room put it in the space between rooms before you checked.
you will check and find a ball with a note of the time to go back to, which will be just after the first one left the time with the dispenser, the dispenser will be pulled again and it will give the next ball with a time slot.
go back to the same time in the other room as set before, and put it in the space between rooms before you look again.
it will have the next time to go back two making sure you won't meet your self.
this will repeat 100 times (or how ever many times you have it go.) until it runs out of balls with times written in it.
you then go back into the room but you don't put anything in the space between the room, thus completing the loop.[/spoiler]

[leaf]

I... think I understand what you're trying to say? It just seems pointless, and I'm not completely sure I understand who is doing the checking when.

Anyway, what you mentioned there reminded me of Time loop logic, using a time machine to solve computational problems in polynomial time.

...unfortunately, time loop logic relies upon an ontological paradox. Where did that information come from to begin with? Some information was sent back into the past and received there, then, that same information is taken later and... sent back into the past. The information has no source.

Aaaaaaand, this is why I hate thinking about this stuff >_>

[zman9000]

ah but it does have a source.

everything is set up by one person, the device is in the past, the notes are taken from the past and put into the future.
this makes 100 different dimensions that self loop and then rejoin the time line leaving no differences.

and say you wanted all 100 notes to end up in the world and not have 99 or 100 of them go away.
then have them sent to the future after each note is read and sent to a different time one after another.

the time line would look like this (just 10 instead of 100) lines from left to right are the flow of time. and the top and bottom time lines are connected.

             /============/
             /============/
---------/============/----------
            /============/
            /============/

if that doesn't make sense... think of it like this, take ten pieces of string in a straight line, grab both ends and push to the center. they fan out making 10 lines that curve out then back in. in the end, everything is as it was before and all time lines are exactly the same.

[Misery]

The way I want to see it, the universe consists of a single, constantly changing state. Which is to say, only the present ever exists, and time is a way to describe that phenomenon of change. According to this view, no kind of time travel, loops or paradoxes would be possible.

With that said, I think I'm just going to stay out of this one -_-

[Aile~♥]

Problem with that is that from what my grade 11 physics stuff says, time is the 4th dimension. Consider that time is also relative, and I'd say that makes time travel absolutely possible in some form. Though, whether it could even technically be considered time travel is another question entirely.

[leaf]

Well, time travel toward the future is entirely possible right now. Twin paradox, anyone?

Anyway zed, I took another look at what you were saying before. I think I understand what you're getting at better now. It actually does make some sense. But... while it seems to work on the surface, it still has some problems.

You, in the present, check the space, find nothing, and travel back in time to send something to the present. However, since you're the one sending it, you would have no reason to go back to the present and receive the same thing. You return to the present and continue living your life. Now, let's say sending a ball to the present did change it, and a new you (we'll call it "you #2"), receives the ball sent from the past. The problem is, this new version of history never has you #1 going back in time to send the ball in the first place; it just spontaneously appears there. The cause of the ball appearing in the space is because you #1 went back in time and changed the past, but... you #1 does not exist in this timeline. As a result, you #1 was essentially "created" in this timeline, and then subsequently "destroyed" upon leaving.