Time Travel Paradox

[mesoforte]

Ah. Back to time non-existent time paradoxes, are we?

Without nitpicking every detail of World War II, I think it's worth pointing out that the 30's were so volatile that even the broad strokes could easily have been different. What if it was a left-wing party that had led Germany against the allies? Or merely a normal right-wing party uninterested in world order? A Britain or France focused on dive bombers - or an early adoption of anti-tank weaponry - might have given us cause to remember the conflict as no more than the "Second Franco-Prussian War". What if the Soviets had eagerly jumped onto the Nazis backs while they were busy fighting in France? I kind of wonder what sort of outlook America would have today if the we hadn't fought a major war since 1917.

A lot worse tech and economy-wise. The destruction and rebuilding after WWII pretty much made the monolith that was the American economy afterwards.

 

[Shoggoth2588]

Is it string theory that says for every point in every day for every person, each decision said person makes kind of splits reality. There is the reality in which they made that choice (say, by eating that pack of pop-tarts) and the alternate reality in which they didn't.

I think the same would apply to time travel. If you go back in time and change something, you continue living on knowing that the reality you came from had a Hitler, had a WWII, had a Holocost. When you get to your new timeline, that doesn't stop you from remembering the old time line. You know that you went backwards in time and killed Hitler but when you return "home" you may find that you're a stranger in a strange land. You may not officially even exist anymore. Also, when you try telling people about Hitler, the Holocost and, WWII they'll think you're crazy either because everyone knows WWII started in 1947 when Japan launched an armada of walking battle tanks (or something like that).

 

[The Virgo]

Why do people always reference killing Hilter in relation to time travel? I can think of some 'worse' people, Stalin, Khan... Michael Bay. In all seriousness, humans cannot bear our minds around time travel, its just how we process things. Because whenever I start up a talk, it always ends up turning into a subject about singularities.
Yeah we know how to do time travel, exceed or match light speed. But the conseqences to killing Michael Bay or whatever are out of our reach.

While killing Michael Bay would benefit everyone...actually the killing of Stalin would have likely causes Hitler to win the 2nd World War.

He would have easily invaded and conquered Russia, and not being attacked from both sides, would have probably made landfall in the United States sometime around 1949.

Agreed ... for the most part.

Yes, without Stalin, Hitler would have probably rolled right into Moscow, since there wouldn't have been Stalingrad ... well, there would have been a city there, but the reason why it was so important for the Russians to hold the city was because for the city named after the leader to have fallen into the hands of enemy would bad for morale.

So without Stalin, the battle of Stalingrad would have probably been another city battle while the Russian army fortified in Moscow.

However, I doubt Hitler would have invaded the United States. It is totally impossible for a nation whose (according to http://www.tacitus.nu/historical-atlas/population/germany.htm) population in 1939 was 8.7 million to occupy a nation the size as the US. And Japan wouldn't have been able to be of much help either to hold a nation several hundred thousand miles in area. It is totally impossible.

 

[Dr Pyramid Head]

I would say that if you caused such a thing to happen, you then travel in a time stream not of your own world. Because of the new event you live in a parallel dimension where all the inhabitants of said world can't remember what happened on your world, only theirs, since it didn't actually happen.
Think of time as a river. The water flows in a direction and all the people of a stream travel along it. There is no way to travel the other way or cross land to another stream.
And say that there are rocks in those streams. And that you, as one of the inhabitants of the neverending stream, can switch to any point within your own stream, but not any other.
So you travel backwards until you meet a point which is littered with a massive amount of rocks. You remember how the placement of rocks there caused the stream to move. And you decide to interfere with the placement, changing the way the stream moves. There a new stream is created and leads somewhere else. YOu follow it, and you realize that eveyone you know (And everyone you don't) respond to your question as to what happened in a drastically different way, as this is a cause of what you did.
So you created a reality where only you remember two different outcomes of a situation, whereas the original inhabitants of each dimension only rememeber their version of events. So unless you change the situation to fit the exact version fo what happened in your world (Which is nigh-impossible, I speculate)you cannot return.


The rocks represent the certain criteria that effect the outcome. The change of these rocks (Or criteria) create a different outcome, resulting in two streams.
What a horrible metaphor I have made.

 

[Grospoliner]

I was thinking the other day after watching the new Torchwood (and wondering when the new Doctor Who will come out) about time travel, when I thought of something: If you go back in time for the purpose of changing an event, that would create a paradox.
Say if you do back in time to kill Hitler before the Second World War, and you succeed, WWII is averted, many lives are saved, doesn't this create a paradox? In the future of that time, Hitler died before he did anything historically significant, and since he would have no historical importance, you would have had no reason to kill him, or likely even know of him, so you wouldn't go back in time, and he wouldn't be assassinated.
If you go forward in time, for any reason (unless someone came back in time, and told you to change a future event) this wouldn't happen, as it wouldn't change the present history.

I don't know if this is a particularly original thought, or if I am completely wrong. The scenario above just applies to out known rules of time, not parallel universes, or fixed points in time.

This only creates a paradox if we're functioning within the Copenhagen understanding of quantum physics. In it, all of time and space is deterministic, meaning that once it can be defined entirely at one point, we can then extrapolate in either direction and determine what will happen, as every causal event will have only one outcome. Thus, traveling back in time to kill Hitler, will create a paradox as, should he not exist, you would never have had reason to travel back in time in the first place.

However, the many-worlds interpretation of quantum physics provides a potentially workable resolution to the whole time travel paradox problem. In the MWI understanding, every causal event creates not only the resultant effect you are a part of (your world track), but an infinite number of infinitely diverging alternate world tracks in which every possible outcome for every possible causal event occurs. As such, in MWI, a potential time traveler could indeed travel back in time to kill Hitler without generating a paradox as the actual causal event of killing Hitler would generate an entirely new world track.

The real problem comes when the traveler attempts to return to his own time, at which point a number of possible outcomes could potentially occur. 1) Nothing would change as the traveler returns to his own world track, illustrating the futility of time travel. 2) The traveler would return to a radically altered world track, as if nothing ever happened, and either feel radically out of place or forget anything ever happened. 3) The traveler would be unable to return to his own world track as the physics involved in sundering time and space are woefully complex and require an monumental undertaking of Grecian Divinity scale that even Zeus himself would be hard-pressed to replicate with the most advanced of technology, let alone the pathetic equipment available in World War 2 era Europe.

As to which interpretation of quantum mechanics is correct... Well no one can really say as of yet. There is much conjecture and hypothetical mathematical evidence for both, be they the legendary works of Einstein or the random unpredictable decay of some radioactive isotopes (or the wonderful fun of dual slit electron experiments). So as they say...

"Time will tell... Sooner or later... time will tell."

 

[FalloutJack]

I was thinking the other day after watching the new Torchwood (and wondering when the new Doctor Who will come out) about time travel, when I thought of something: If you go back in time for the purpose of changing an event, that would create a paradox.
Say if you do back in time to kill Hitler before the Second World War, and you succeed, WWII is averted, many lives are saved, doesn't this create a paradox? In the future of that time, Hitler died before he did anything historically significant, and since he would have no historical importance, you would have had no reason to kill him, or likely even know of him, so you wouldn't go back in time, and he wouldn't be assassinated.
If you go forward in time, for any reason (unless someone came back in time, and told you to change a future event) this wouldn't happen, as it wouldn't change the present history.

I don't know if this is a particularly original thought, or if I am completely wrong. The scenario above just applies to out known rules of time, not parallel universes, or fixed points in time.

Well, believe it or not, I actually understand Doctor Who and Torchwood for all its timey-wimeyness. Put simply, our paradox pretty much creates new reality around it, as the universe doesn't die because of one actor's mistake. I support the idea that parallel worlds play out with all possibilities, which is why I'm fairly certain you can't kill yourself with time travel OR be your own grandfather. (Sorry, Fry.) You simply invalidate the universe you were in and your status in it in favor of a different one that's changed around you, foreign to how you remember things.

This is all assuming a Stable Time Loop did not occur.

 

[Aaron Frederick]

Time, it is set in stone. Think about it this way. Lets say that you go back in time to try and... i dont know... Kill Ghandi (i couldnt think of anything else). Because you went back in time, Whatever you did had already happened in the future you were living in beforehand (because it had already happened) Therefore, by traveling in time nothing would change, everything would happen in the exact same way it happened in recorded history because whatever you did that day IS recorded history, BECAUSE IT HAPPENED IN THE PAST! i get so tired of these time travel threads.

EDIT: Also, you may want to stop basing your knowledge of time travel on a fictional TV Program

 

[idodo35]

I don't know if this is a particularly original thought, or if I am completely wrong. The scenario above just applies to out known rules of time, not parallel universes, or fixed points in time.

well its not very original but it is very true...
anyway thats why you can only travel forward!

 

[Karma168]

exactly, its actually...

Damn Ninja'd. Anyway Doctor Who has an mechanic for this; there are fluid and fixed points in time, the fluid ones can be changed but the fixed ones have to happen (see; pompeii episode).

WW2 would likely be fixed, Hitler maybe not. This means you go back kill snd kill Hitler, WW2 would still happen; someone else would just take Hitlers place, someone then goes back to kill him (thus leaving hitler alone) and Hitler takes over. As the timeline changes the target changes. There would be no way to avoid WW2.

 

[Woodsey]

The Doctor explains this in two ways, first off, some events in time are time locked and cannot be changed, these are generally large events that would cause too many problems if they were undone, like the Dalek-Timelord war or possibly, WWII.

The second is that when you are traveling, the knowledge that you have and the events that you cause are now your existence. So for example, you would be aware of the changes, but everyone else wouldn't be in the future.


So in summary, Hitler probably couldn't be killed because WWII is time locked and even if you could kill him, you would still remember the atrocities committed, but everyone else wouldn't.

But that's just in the world of Doctor Who, which lacks almost any semblance of internal logic.

 

[standokan]

My conclusion is parallel dimensions, a paradox creates two streams, one in which the time travel has a effect and one in which it never happened. It's the best I could come up with/

 

[grimmreapervi]

Why isn't anyone considering the laws of conservation?

 

[thejdcole]

500 years ago we thought that the earth was flat. I'm sure in 500 years time people will look back and laugh at our current understanding of space-time.

 

[Dr Jones]

anything to do with timetravel is to complicated as ends in a paradox. except maybe traveling back in time as an observer.

That is true (though observers would undoubtedly do some shit too), but it isnt necesarilly true. This all depends on if "Novikov's self consistent theory" proves to be right. Basically what it says is that if you travel back in time to burn a house and you return, nothing will have changed. That house burning has always been a part of history. So at your age of 4 you were there too burning a house. So if John Wilkes was about to kill Abraham and you could stop him, you couldnt. It would be physically impossible due to the laws of physics (according to this theory), basically you would end up fucking up, though in the end that was a part of history.
ALTHOUGH this creates the question "Who started it then?", if you were Booth and went back in time to kill Lincoln (which had already happened in your youth), then who killed him first? This is what's called the Bootstrap paradox (i believe).

Of course its just theories. I like the self consistent one. But the generally believed butterfly is likely the truer.

 

[Zenn3k]

Why do people always reference killing Hilter in relation to time travel? I can think of some 'worse' people, Stalin, Khan... Michael Bay. In all seriousness, humans cannot bear our minds around time travel, its just how we process things. Because whenever I start up a talk, it always ends up turning into a subject about singularities.
Yeah we know how to do time travel, exceed or match light speed. But the conseqences to killing Michael Bay or whatever are out of our reach.

While killing Michael Bay would benefit everyone...actually the killing of Stalin would have likely causes Hitler to win the 2nd World War.

He would have easily invaded and conquered Russia, and not being attacked from both sides, would have probably made landfall in the United States sometime around 1949.

Agreed ... for the most part.

Yes, without Stalin, Hitler would have probably rolled right into Moscow, since there wouldn't have been Stalingrad ... well, there would have been a city there, but the reason why it was so important for the Russians to hold the city was because for the city named after the leader to have fallen into the hands of enemy would bad for morale.

So without Stalin, the battle of Stalingrad would have probably been another city battle while the Russian army fortified in Moscow.

However, I doubt Hitler would have invaded the United States. It is totally impossible for a nation whose (according to http://www.tacitus.nu/historical-atlas/population/germany.htm) population in 1939 was 8.7 million to occupy a nation the size as the US. And Japan wouldn't have been able to be of much help either to hold a nation several hundred thousand miles in area. It is totally impossible.

Yes, in that respect you are correct...but Hitler wasn't exactly the type to let a little thing like "plausibility" stand in his way.

In fact, early dictations by Hitler, which were locked away for a long time, proved that after he took Russia and England, he was planning an attack on America. He was even building "America-Bombers" http://en.wikipedia.org/wiki/Amerika_Bomber

So the intent to attack America directly existed...being able to occupy the US might have been a logistical impossibility, but that doesn't mean the Nazi wouldn't have tried.

 

[ShindoL Shill]

exactly, its actually...

Damn Ninja'd. Anyway Doctor Who has an mechanic for this; there are fluid and fixed points in time, the fluid ones can be changed but the fixed ones have to happen (see; pompeii episode).

WW2 would likely be fixed, Hitler maybe not. This means you go back kill snd kill Hitler, WW2 would still happen; someone else would just take Hitlers place, someone then goes back to kill him (thus leaving hitler alone) and Hitler takes over. As the timeline changes the target changes. There would be no way to avoid WW2.

my way you might be able to. because the Princip was the last assassin, he had the one chance (outside the cafe) to kill the archduke. kill him and you prevent WW1 and therefore WW2.

 

[crudus]

I was thinking the other day after watching the new Torchwood (and wondering when the new Doctor Who will come out) about time travel, when I thought of something: If you go back in time for the purpose of changing an event, that would create a paradox.

Spoiler: Ahem

The very first part is definitely true, but as a Doctor Who fan you should know that whole line(also, new episode this Saturday). In all seriousness, the universe seems to have a lot of "built in" paradox "fail safes". They are weird things the universe does to prevent a certain law from being broken. For example lets say there is a ship traveling 1 mph under the speed of light. A person would then think "hey, I could just run from one end of the ship to the other and go faster than light". No, various effects prevent this. I am sure the universe would have a paradox "fail safe" for time travel as well.

 

[The Artificially Prolonged]

You cannot go back in time without creating paradoxes, as virtually anything you do in the past could be considered a paradox. As a wise man Abe Simpson said, "if you ever go back in time, don't step on anything!"

 

[thejdcole]

500 years ago we thought that the earth was flat. I'm sure in 500 years time people will look back and laugh at our current understanding of space-time.

*slap*

The shape of the earth has been common knowledge for at least the last 2000 years. All this bullshit about people being morons who thought the earth was flat is something that was invented in the 18th century.

As much as I appreciate the slap, why does what i said matter. It is an analogy that many people will understand and can relate to. And the point that I was making had little relevance to what peoples perception of the earth 500 years ago actually was.

What I was trying to say, in case you missed it, was that at the moment I believe that our understanding and comprehension of space time is limited. And much like how science 500 years ago is far better understood and comprehended today, I believe in the future people will look back at our current understanding of time and laugh.

(But thanks for the correction, it is something I did not know, and has made for some interesting internet reading).

 

[TimeLord]

So you want a discussion about time do you?

Point 1

[HEADING=1]The Blinovitch Limitation Effect[/HEADING]​

The Blinovitch limitation effect is a physical, real limitation which prevents time travellers from interfering with their own history. It has two manifestations, one which prevents time travellers from changing their own past, and one which prevents a time traveller from meeting themself.

The key word here is "Limitation"; that is, the effect limits the amount of interference in the past as opposed to completely prohibiting it. Although it still isn't recommended for the reasons below.

In its first form, the effect is simply a time loop. Blinovitch stated that time is non-linear, and can become circular. A time traveller attempting to change their own history, for better or worse, will simply just create a time-loop, where his or her actions in the past are pre-destined and in fact have already happened.

Basically making the travellers future more "fate" oriented as events are destined to happen the same way again and again.

Time loops are paradoxical in nature, and to occur, time travel across time-streams must have happened. Of course, visiting your own personal past is only possible by crossing your own time-stream.

The Blinovitch limitation effect also has a second form, in this scenario it manifests itself as a force which prevents time travellers from interfering directly with their own past selves.

Basically, someone can't re-do something they have already done.

The force which intervenes may take any known form, manipulating chaotic and quantum variables in a weak manifestation, and manipulating explosive energies in a more violent manifestation. This form of the Blinovitch limitation is related to time eddies, a phenomenon which occurs when localised time runs in reverse, or circles round and round in a whirlpool like fashion.

It may be surprising to learn that both forms of the Blinovitch limitation effect can be circumnavigated.

To cancel out the time-loop in the first instance, it is necessary for an external time-traveller not previously connected with the time-loop to interfere with the creation of the time-loop. This may sound like interfering with a past-event, but there is a subtle difference here. A time-loop is not a real event. Once a time-loop is destroyed, the energy it had consumed to create its alternative reality is released back into the real universe.

Note this time that the destruction of a time-loop is a real event, and any attempts to change this will prevented by the second form of the Blinovitch limitation effect.

However, the second Blinovitch limitation effect can itself be avoided. The trick is simple: cross time-streams. The Blinovitch limitation effect only occurs as a result of a time-traveller meeting himself in his own time-stream. By meeting oneself in another time-stream, the effect does not take place.

Basically, in the event a time paradox...
[sup]sorry, I mean:[/sup]

[HEADING=1]TIME PARADOX[/HEADING]
ahem...

...the event can still be altered based on the circumstances to correct the The Blinovitch Limitation Effect.

and

Point 2

[HEADING=1]Travel to the Past[/HEADING]​

"Every point in time has its alternatives...The future can be shaped - the actions of the present change the future. To a small extent a man can change the course of history. It takes a being of ... almost unlimited power to destroy the future."

When travelling to areas in your personal past, the question most often asked is, "has time travelled already happened?". This is another way of asking whether or not the past in immutable. For example, has it already happened in history that a time-time traveller from the future has travelled back, or does travelling back change history? The two alternatives are usually summed up thus:

1] Time travel has already happened -- the past destination is really an extension of your present. Nothing you do will change history, and everything you do will fullfill history, barring abnormal interference. This is also described as a soft time-loop.

2] Time travel has not already happened. In this case the traveller risks the possibility of creating an alternative universe.

The distinction is far from academic. Let us consider an example:

Is there one version of this event? Do they agree on the details? Does Andy see Borak from the future? Certainly Borak should see Andy. Whilst travelling in time you will find that a meeting such as the one described above simply cannot happen. Basically Andy would come and go, and Borak would not be there. Borak then would not be able to set his coordinate to day 100 12:10. In fact, the nearest coordinate would be day 101 12:00. This prevents the potential paradox mentioned above. The enforcement of time-streams creates urgency, as one cannot wait around and then act on an emergency distress call, as it may well preclude the ability to answer.

Without a Time Machine enforcing travel to within time-streams, the following may of happen:

If Borak were to attempt to contact Andy, he would find himself up against the Blinovitch limitation effect. As Andy has arrived "first" (spatial-temporal destination is a sub-topic for a later thread) his version of the events are immutable. And since he didn't see Borak, Andy cannot do anything to change that.

To summarise, the past is ordinarily immutable. What has happened has happened. Everything someone does in the present is recorded in the past. So what happens when someone tries to change history? Various phenomena occur as you battle with time. If someone attempts to change the past of their own time-stream, the Blinovitch limitation effect comes into play. If someone attempts to change the past of someone else's time-stream, they will find this immutable. It is possible, as the quote above suggests, for a being or machine of extraordinary power to distort space-time so much as to force the creation of an alternative reality which becomes the default reality for all time-travellers. Basically creating a parallel universe. (ala Back to the Future 2)

Both of those pieces are from these threads below.
I'll just leave these links here.

The Blinovitch Limitation Effect [http://www.escapistmagazine.com/forums/read/18.201912-A-Discussion-about-Time-The-Blinovitch-Limitation-Effect]
Time Streams/Illusion of Time [http://www.escapistmagazine.com/forums/read/18.203130-A-Discussion-about-Time-The-Illusion-of-Time-Time-Streams]
Travel to the Past [http://www.escapistmagazine.com/forums/read/18.204135-A-Discussion-about-Time-Travel-to-the-Past]
Travel to the Future [http://www.escapistmagazine.com/forums/read/18.208546-A-Discussion-about-Time-Travel-to-the-Future]
Time Tracks/Time Friction [http://www.escapistmagazine.com/forums/read/18.218644-A-Discussion-about-Time-Time-Tracks-Time-Friction]
Time-Loops [http://www.escapistmagazine.com/forums/read/18.224218-A-Discussion-about-Time-Time-Loops]
The Laws of Time [http://www.escapistmagazine.com/forums/read/18.231707-A-Discussion-about-Time-The-Laws-of-Time]