Are these predictions about the Pacific coastline true or just a coincidence?

[TheUnknown]

if you put a man in a room, and set the clock to 12:30 and have him wake up from a banging noise (so he can wake up at 12:30)... and set the day to Monday April 4th on his calender... record him and watch what he does... take that man, brain wash him... leave his calendar alone, set his clock to 12:30 again, and do it all over, are you certain he will make the exact same choices? is this in any way different from parallel universes? and if so, how? are we predetermined to make decisions? and if so, why do you think this? If we commit the same actions in every single universe, then sending a time traveler back to ONE of them, would totally mess it up... then what happens? just that one universe is messed up, and the rest of us go on unparallel to it? or is it instantly and mysteriously "destroyed" ...? nice convo btw :)

 

[Ich]

Those multiple universes are not a theory, they are rather an interpretation of quantum mechanics which happen to solve some paradoxes of time travel.
Besides that, nobody knows if time travel really exists and so all this thread is speculation, more or less a "what if" scenario. It´s just fun talking about and letting your thoughts flow. Hope you don´t have a problem with that.
p.s. multiple universes are thought by some people to be a rather straightforward interpretation of QM; the only real alternative today is the "copenhagen interpretation" - I´d like to see your reaction to IT.

 

[moving finger]

No, I agreed that if the machine is 100% guaranteed to work properly (to give the opposite output as its input), then the only self-consistent escape would be for no time travelers to feed its ouput back as input. However, if the machine has even a small chance of malfunctioning and returning the same ouput as its input--say, an 0.000000000001% chance--then there will be at least some self-consistent histories in which a time traveler does feed its output back to it as input, and it malfunctions and returns an output identical to its input. Such histories may be much less likely than histories where a time traveler doesn't mess with it at all, but they are not nonexistent.

Agreed. I did make the initial assumption that the machine would not malfunction, but I agree with you that if there is a non-zero chance of malfunctioning then there would be at least some self-consistent histories within GR which involve a time-traveller predicting the machine's output. However I believe the overwhelming odds would be that such a prediction would not be possible (because the probability of the machine malfunctioning is so small), hence for each possible universe where such a prediction is made, there would be an overwhelming number of possible universes where such a prediction cannot be made. And I believe similar statistics would be true of the prediction of human actions.

And human behavior is so complex that I doubt there is any situation in which you could say, without knowing the details of what was going on in a person's brain (and without having traveled in time), that they were 100% guaranteed to do anything. Imagine humans have spread throughout the galaxy, and there are 500 quadrillion humans alive on different planets. If I go to each one pretending to be a time traveler and say "I know you will have eggs tomorrow for breakfast", then each one is filmed having breakfast tomorrow and all the films showing people having something other than eggs are thrown out, are you suggesting we could be confident there wouldn't be a single film in which someone did decide to have eggs the next day?

Well firstly if you do go to each one and merely pretend to be a time traveller then you do not have infallible foreknowledge and it makes no difference whether they have eggs or not does it?
But even if you were a real time traveller, I am not saying this. What I am saying is that I believe there would be an overwhelming number of instances where people "could" manage to falsify your so-called infallible prediction, and hence by your own account the prediction is simply not possible and therefore cannot be made in the first place.

Yes, that is one solution, and it may be that it's by far the most likely one, but there would be at least some self-consistent histories where a person was told what they were going to do by a time traveler, even if they were extremely rare.

I think we agree.

I don't agree there is any reason they "simply cannot" have such knowledge, and you have given no real arguments for why they can't besides a vague feeling of free will (even though you know this doesn't apply to the computer simulation thought-experiment).

No, it's nothing to do with free will, and yes I have in fact given a very real argument supporting the idea that agents cannot exercise infallible foreknowledge. It’s to do with self-referential loops. We have seen that even a simple machine can negate the possibility of usefully using apparently infallible foreknowledge through the use of a very simple self-referential loop, and the same idea can be extended to humans and other agents.

If it's complex, then even if it decides to try to act like that binary machine, it may get distracted, or change its mind, etc.

It "may" fail, but I believe in the overwhelmingly likely number of cases it will succeed.

Well, surely you agree it is also possible for any sufficiently complex agent to decide to see what his friend eats on thursday and then go back in time and tell him on wednesday--yet your solution to the self-consistency problem was that no agent would ever choose to do so.

By your own argument - there must be instances where the agent CANNOT do as you suggest if we are to maintain self-consistency. All I am arguing is that these cases will be the overwhelmingly most likely cases. However cases where agents DO travel back in time and DO successfully predict another agent's future, whilst theoretically possible in principle (at least according to GR as it stands today), will necessarily be extremely rare.

So why doesn't your argument "I cannot see why any sufficiently complex agent could not behave in this fashion" also apply here? And if you can see that self-consistency might imply that no agent would choose to give a friend foreknowledge in this way, why can't you also see that it might imply that no agent would ever choose to behave like your binary machine, or why no agent would ever choose to kill his mother before he's conceived?

I never said that it was not possible for an agent to choose not to kill his mother. Of course an agent can choose not to kill his mother, that is not the issue here. What I objected to was the implication that no agent could ever kill his mother, even if he so chose.

The second one is just another way of saying that any time-traveling agent is "constrained" not to choose to tell his friend what he'll eat the next day, so I don't see why you'd prefer the second to the first.

There is a big difference.
One solution (the self-consistent histories solution) implicitly assumes that both time-travel and infallible foreknowledge are possible, and that somehow additional “constraints” are placed on agents’ abilities in the present time to ensure consistency with both.
The other solution (the impossibility of infallible foreknowledge) does not assume time-travel, and does not place any additional constraints on agents’ abilities in the present time. In addition, it might turn out in the end that we find there is something wrong with GR as it stands, and time-travel is simply not possible (which would be consistent with the “impossibility of infallible foreknowledge” solution).

Anyway, like I said, as long as it is possible for an agent to occasionally do exactly what he is predicted to do, then there should be at least some self-consistent histories in which he does receive such an infallible prediction.

Agreed, but this neither proves that time travel is possible, nor does it prove that such histories actually exist (only that they are possible in principle assuming GR as it stands).

If we're getting into the domain of likelihood, it also seems unlikely that time travel would be widely available yet no time traveler would ever decide to make an infallible prediction, so perhaps the most likely type of self-consistent history would simply be one where sentient beings simply never invent time travel, even if it is permitted by the laws of physics.

This is closer to what I believe is the truth – but I would go even further and suggest the simplest solution of all is that in fact time travel is not permitted by the laws of physics, we just haven’t realized it yet.

MF

 

[TheUnknown]

Those multiple universes are not a theory, they are rather an interpretation of quantum mechanics which happen to solve some paradoxes of time travel.
Besides that, nobody knows if time travel really exists and so all this thread is speculation, more or less a "what if" scenario. It´s just fun talking about and letting your thoughts flow. Hope you don´t have a problem with that.
p.s. multiple universes are thought by some people to be a rather straightforward interpretation of QM; the only real alternative today is the "copenhagen interpretation" - I´d like to see your reaction to IT.

It's not my opinion though, I'm pretty sure i just proved it to be factually flawed?

 

[TheUnknown]

or if i didn't prove it wrong, i proved if time travel is possible we can destroy the universe accoring to this theory.. i'll go check out that other stuff btw thanks for the link :)

 

[moving finger]

haha indeed... we are just very sophisticated curious animals. ok, ok, i meant... what if i went back in time, supposing that i could warn someone of some catostrophic event that is going to happen(not in nature... assuming the Earth ages the same and almost all the same geological catastrophes happen in synch with normalcy to our Known universe/world)... how do i know this will happen in their world?

How do you know there is more than one world?

how do i know if that person(s)even exist in where i am going?

You cannot warn soemone who does not exist.

on a differnt subject. if we do have parallel universes in the world

That's a very big IF

.. as far as living things go? and we all just happen to be born in these parellel universes because of some unknown mystery yet to be figured out. Then why go back? to save yourself in another universe which is you... but won't actually effect "YOU"

One wouldn't necessarily want to go back to save oneself. As I said, humans are curious animals, or maybe we just want to escape from our existing future and find another future?

... i think there is a huge information gap involved with the discussion of time travel, and there always will be until we can figure it out (which i do believe is not to far off), Also about the Dad thing, i meant if my dad has lost that sperm when i went back in time.. acknowledging the fact that we have free will in all of these parallel universes.

lol - what is "free will"?

Then where i went to find myself, i would not find... but i would still find my Dad... and possibly a child that took my place :)(being that he still marries my Mom) very interesting... love the feed back, i think this is brain food, not tuna. ha. Maybe I'm missing something here? but i don't see how even in parallel universes... (whatever that means in full.. i'd love a total explanation...) how are we denied the right to free will?

Define free will first, then we can debate whether it exists...

MF

 

[moving finger]

You can tell your brother that he will eat two eggs only if this won't cause him to not eat two eggs according to the 'select valid spacetimes' theory.

It's not that, given the assumption that your brother has free will, he literally CAN'T deviate from this page, it's that he WON'T. All the timelines where he decides not to are destroyed, therefore he must.

Your problem is that you're mixing science with free will.

Your problem is that you assume I am arguing in favour of, or on the basis of, free will. Read the posts - I am not.

There will be an overwhelming number of times that you cannot infallibly tell your brother he will eat two eggs, because he can prove you wrong. Therefore the vast majority of times you simply will not be able to make the infallible prediction (you can make a prediction, yes, but most times you will be wrong). This has nothing to do with free will, but everything to do with self-referential loops.

MF

 

[moving finger]

nobody knows if time travel really exists and so all this thread is speculation, more or less a "what if" scenario. It´s just fun talking about and letting your thoughts flow. Hope you don´t have a problem with that.

I have no problem with it, Ich, but if you read the first post in the thread you will see what its all about. According to GR as it stands today, time travel is theoretically possible - ie it is not ruled out by current theories. In this thread we are simply exploring some of the implications of that.

multiple universes are thought by some people to be a rather straightforward interpretation of QM; the only real alternative today is the "copenhagen interpretation" - I´d like to see your reaction to IT.

I disagree. There are a number of interpretations of QM apart from Copenhagen and multiple universes, including the Hidden Variables interpretation. However the various interpretations of QM are off-topic for this thread.

MF

 

[Ich]

or if i didn't prove it wrong, i proved if time travel is possible we can destroy the universe accoring to this theory.. i'll go check out that other stuff btw thanks for the link :)

You just found out that time travel brings you a great deal of trouble, vanishing universes maybe the least of it. People here know that, and that´s why they´re discussing a lot.
BTW , time trave really is speculation, but i´m sure there are two or three things about the behaviour of our universe which would lead you to PROVE it wrong in less than five minutes ;)

 

[moving finger]

without free will we don't have science...

? pardon? what does science have to do with something called free will? What is this thing you call free will anyway?

it's not a problem.. or maybe it is? maybe this means time travel can never exist. If there is someone living that is me right now in a parallel universe...

How can someone else be you, unless they really are you, and you them?

why are you so certain he will not get in a car crash and die tomorrow whereas here, i keep on living?

that's the whole idea of parallel universes, that different things can happen given the same starting conditions

Please tell me where science explains that. So you're image of parallel universes is a bunch of robots programmed running around doing the EXACT same things with no free will? that is not Science...

free will, what's that again?

MF

 

[Ich]

moving finger,

admitted, GR allows for time travel under certain conditions. It also allows for wormholes and superluminal velocities, if you just can gather enough exotic matter. Don´t misunderstand me, I welcome discussion about it and enjoy it myself. Nevertheless it´s speculation, because we´re just beginning to explore the consequences of GR - already knowing that it cannot be strictly correct (TOE and so on).
To QM, i thought Bohm ran into problems with his hidden variables, and decoherence is up to date. But You´re right, that´s another forum.

 

[moving finger]

BTW , time trave really is speculation, but i´m sure there are two or three things about the behaviour of our universe which would lead you to PROVE it wrong in less than five minutes ;)

ok, Ich, and with the deepest respect, go ahead and be my guest and try to prove time travel "wrong" - I'll be generous and let you have 5 days, never mind 5 minutes

MF

 

[Ich]

ok, Ich, and with the deepest respect, go ahead and be my guest and try to prove time travel "wrong" - I'll be generous and let you have 5 days, never mind 5 minutes

MF

sorry, moving finger, this one was meant for theunknown. I didn´t want him to prove time travel wrong, but out whole universe.

 

[TheUnknown]

You just found out that time travel brings you a great deal of trouble, vanishing universes maybe the least of it. People here know that, and that´s why they´re discussing a lot.
BTW , time trave really is speculation, but i´m sure there are two or three things about the behaviour of our universe which would lead you to PROVE it wrong in less than five minutes ;)

Don't get me wrong! i am not trying to prove time travel wrong, i am trying to prove it right.. but first we need to ask questions about theories, and get rid of ones that are so absurd, if we don't.. we'll never move forward... vanishing universes? i mean c'mon.. destroying the universe because you went back in time 2 times, once told your brother he was going to eat 2 eggs... he did.. so the ones where he didn't suddenly blew up, or vanished, then go again and tell him he's gunna eat two eggs, and he does.. so they vanish too, so then what are you left with? where did that theory come from? where do the universes go if they vanish? what happens to them? it sounds... extremely wishful to me. It's not that simple... well it can't be! or we'd be destroyed already, because obviously the universe is omnipresent when it comes to thinking on a time travel level, so we could have already experienced time travelers? or is it not... do you think we are the first earth/universe to reach 2005? i believe all the questions i have posted here and in my previous posts need to be applied to all time travel theories... it can't be that universes dissapear, you could not just destroy a whole dimension of Earth just from time travel, or I'm sure we'd be destroyed by now being that the universe is omnipresent ... it's really strange isn't it? arg... maybe it's only omnipresent up to our current and previous dates.. would this explain no time traveler visits? really weird.. now I'm lost lol ah.. maybe if time travel exists, then it is not used much... don't you think? or we would have seen something by now? ( i mean does not exist... being that the universe is omnipresent... no futuristic people have visited us yet saying they are time travelers with concrete evidence)

 

[moving finger]

moving finger,

admitted, GR allows for time travel under certain conditions. It also allows for wormholes and superluminal velocities, if you just can gather enough exotic matter. Don´t misunderstand me, I welcome discussion about it and enjoy it myself. Nevertheless it´s speculation, because we´re just beginning to explore the consequences of GR - already knowing that it cannot be strictly correct (TOE and so on).
To QM, i thought Bohm ran into problems with his hidden variables, and decoherence is up to date. But You´re right, that´s another forum.

Godel found a solution to Einstein's equations which allowed time travel but did not require wormholes, exotic material or superluminal velocities. It is generally recognised that within GR as it stands, time travel is possible at least in theory. As to speculation - well even the possibility of manned flight was "speculation" until someone had the curiosity and the courage to try to make it happen for real

The only problem with QM (and it's a problem for ALL interpretations, not just Hidden Variables) is that any viable solution must be non-local. This has been (ignorantly) used as a "proof" that no hidden variables theory can work (von Neumann has a lot to be blamed for!), whereas in fact non-local hidden variables theories can work.

MF

 

[Ich]

theUnknown -
absurd things/theories happen to come along every day. I didn´t say tou should believe it. My point was that you can´t actually DISPROVE it, so join the discussion and have fun.
Moving Finger -
agreed to all. Still QM is (at least) strange, and time travel is not shown to be possible.

 

[DaveC426913]

I get it. I get it!


All the thought experiements about traveling to the past and setting up a paradox make the same assumption; they make the assumption that the past is open, i.e. that it has not happened yet, i.e. that it is still possible to shoot one's mom.

The past is not the future. It has happened. We know that you will not return to the past and shoot your mother because it did not happen. (That's the one advantage of the past, that we know what (will have) actually transpired).

This plays right into the concept that time is an illusion, that past and future are merely the myopia of living creatures. If the past present and future have already been painted on the canvas (this is the "block time" referred to), then there is, simply put, no picture of our universe that was painted where a paradox occurred.

Does this mean we do not have free will? Maybe. It doesn't require the preposterous notion that some 'thing' will prevent you from pulling the trigger, it just means that the universe you are attempting to describe wherein those events occurred, is simply not in existence. You did not shoot your mother. Period.

 

[TheUnknown]

How do you know there is more than one world?


You cannot warn soemone who does not exist.


That's a very big IF


One wouldn't necessarily want to go back to save oneself. As I said, humans are curious animals, or maybe we just want to escape from our existing future and find another future?


lol - what is "free will"?


Define free will first, then we can debate whether it exists...

MF

free will... the ability to make your own decisions? if you believe in time travel you must believe in free will... because you have the free will to go back in time and mess with someone and they have thr free will to agree with you, or not agree with you, and the list goes on... when thinking about time travel you MUST incorporate free will, or certainly the universe will end, to many contradicting factors with no free will.. so by my studies over the last 6 months I've come to the conclusion of many things, that is one of them... about warning someone if they do not exist... that was my point! :) if you decide to time travel and warn someone of something.. how do you know if their parents got together and successfuly had you, or the parents of their parents? or their parents? and all the way back to the ice ages, can you imagine the probability of that happening? it all has an effect, if anyone thing is altered the whole world changes. again it's free will at work... you may be way more special than you think, you may be the only YOU in this universe/world/etc. also how could you go back to escape your future? how do you know your future? and if you did, and we did, don't you think we'd stop our own future from happening instead of escaping? we can never know our future with 100% accuracy... or so i believe, and if we did escape to another world where there was no time travel what would we tell them? how would we have enough room to fit all of humanity into another worldline? would humans be scattered through multiple universes or many worldlines? would we then warn every worldline of the possible catastrophes that lie ahead? see what i mean? this destruction of universes thing cannot exist... i can't find any reasonable logical explanation of it that i can't contradict.

 

[TheUnknown]

theUnknown -
absurd things/theories happen to come along every day. I didn´t say tou should believe it. My point was that you can´t actually DISPROVE it, so join the discussion and have fun.
Moving Finger -
agreed to all. Still QM is (at least) strange, and time travel is not shown to be possible.

i am having fun! you don;'t like me? :(

 

[Ich]

still have ;)

 

[TheUnknown]

I get it. I get it!


All the thought experiements about traveling to the past and setting up a paradox make the same assumption; they make the assumption that the past is open, i.e. that it has not happened yet, i.e. that it is still possible to shoot one's mom.

The past is not the future. It has happened. We know that you will not return to the past and shoot your mother because it did not happen. (That's the one advantage of the past, that we know what (will have) actually transpired).

This plays right into the concept that time is an illusion, that past and future are merely the myopia of living creatures. If the past present and future have already been painted on the canvas (this is the "block time" referred to), then there is, simply put, no picture of our universe that was painted where a paradox occurred.

Does this mean we do not have free will? Maybe. It doesn't require the preposterous notion that some 'thing' will prevent you from pulling the trigger, it just means that the universe you are attempting to describe wherein those events occurred, is simply not in existence. You did not shoot your mother. Period.

ah very bright, i love it ;) but don't forget the possibility of the multiple worlds theory.. although it is just a theory, it does seem very possible. but you may want to rethink your 'can't go into the future cause it hasn't been done', if there are parallel (again i am just using different theories that i believe possible, since they cannot be proved wrong yet) universes, then the universe would be omnipresent, and you could go into the future, because... if you can go back in time, then you can go into the future, because by going back in time, that means that "the past" is still unfolding at that present worldline... therefore the universe is omnipresent, and the future must also be unfolding as well... aren't astro physics tricky.

 

[TheUnknown]

also the destruction of universes from the consequence of time travelers would not make much sense in the fact that... if you told your brother he was going to eat 2 eggs... and he didn't... then EVERY single Earth/universe... and the people in it suddenly disappear "destroy"... so the only logical possible outcome from then on... would be for him to EAT the eggs right? so now this is where you come in... travel back again, and kill him! then what? uh oh! so he dies in every other parallel universe to.. the way this theory is thought out.. is that the consequence of one worldline effects anther? i don't believe in this because it assumes that EVERY universe where he doesn't eat the eggs is DESTROYED, why?! there is still no explanation for this... therefore if I FORCE him not to eat the eggs... the universe ends? remember all the universes where he HAS to eat the eggs has been destroyed... so am i creating a new universe by making him eat eggs? i hardly think so... this is almost laughable, because that's where this theory comes to an end :-/ it can't be true because it is incomplete and lacks a lot of logic, everytime i read it, it sounds like someone who, don't get me wrong, is very brilliant... but it sounds like their wishful thinking, desperately trying to be made true, and i think i exposed a LOT of faults here to undeniably dismiss it? don't get mad at me ich... remember i am not against time travel.. i am just pro fact, and pro logic and reasoning... i want to prove time travel to be right, and i believe it can be done... but the crazy theories trying to scare people who can't analyze the theory for themselves begin thinking time travel is going to destroy the universes... it's abs... ahhem.. you see what i mean now :)

 

[DaveC426913]

I think the key is that the universe getting destroyed does not happen in "our experience" of time. i.e.: "Yesterday, a universe. Today, not so much with the universe."


But it happens outside of time. i.e that universe just didn't happen.


Same thing as with the double slit experiment. Measuring the photon doesn't destroy the offending path, it makes it that the path did not happen.

 

[TheUnknown]

I think the key is that the universe getting destroyed does not happen in "our experience" of time. i.e.: "Yesterday, a universe. Today, not so much with the universe."


But it happens outside of time. i.e that universe just didn't happen.


Same thing as with the double slit experiment. Measuring the photon dopesn't desotry the offending path, it makes it that the path did not happen.

but that is not reasonable... i mean if suddenly a time traveler came and did something that destroyed our World... we'd KNOW, and he would too! so we did exist! and he knew about it as well as us! he still has to go back to his time knowing we existed(being he survived, which he should, since he is not a part of our universe, unless it suddenly self destructs while he's there... this is why i don't buy this theory again.)... therefore we did exist in time, and our universe was both destroyed in his time and ours. either way you put it for US... he still witnessed his actions destroy our universe. That is very interesting... our existence of time.. i'll have to think about that one for a while, let me get back to you, my brain is scattered right now lol. I still don't believe in universes being destroyed by time travel! :)

 

[TheUnknown]

anyone just looking at this page, i ask you to please read all of them :)! i need some input on this, i am studying this topic very hard, i believe time travel is possible, but so far it is beyond our comprehension... and i am trying to move us forward by dismissing old faulty theories, and possibly create new ones.. if anyone would like to collaborate? because before we try and attempt something that has the potential for a number of universal flaws... we should first theorize logically, and lift up every stone, not turn a blind eye to any suggestion, and look around every corner... humans are amazing... look what one of us can do... put 5 brains together and it's very possible.

 

[DaveC426913]

but that is not reasonable... i mean if suddenly a time traveler came and did something that destroyed our World... we'd KNOW, and he would too! so we did exist! and he knew about it as well as us! he still has to go back to his time knowing we existed(being he survived, which he should, since he is not a part of our universe, unless it suddenly self destructs while he's there... this is why i don't buy this theory again.)... therefore we did exist in time, and our universe was both destroyed in his time and ours. either way you put it for US... he still witnessed his actions destroy our universe. That is very interesting... our existence of time.. i'll have to think about that one for a while, let me get back to you, my brain is scattered right now lol. I still don't believe in universes being destroyed by time travel! :)

No. We know that a time traveller will/did not destroy this universe: it exists.

Brian Greene's book 'Fabric of the Cosmos' shows how time can be seen as an illusion. That both past and future already exist**; it is merely our limited perception that we view time as "passing". Since the future exists, it is impossible to have a future exist wherein a time traveller destroys it in the past. That particular series of events just never happened.



**In a nutshell: Using GR, you can show that one man's past is another man's future. If you slice it just so, the two events can be shown to have happened simultaneously in spacetime.

 

[Raparicio]

Paradoxal time

You can supply the paradoxes, by division of x->x' and t->t' formula of A. Einstein. Now, you work with velocities, and this have no paradoxal time. An example of another post is:

https://www.physicsforums.com/showthread.php?t=69849

where is de paradox? In our minds.

 

[TheUnknown]

No. We know that a time traveller will/did not destroy this universe: it exists.

Brian Greene's book 'Fabric of the Cosmos' shows how time can be seen as an illusion. That both past and future already exist**; it is merely our limited perception that we view time as "passing". Since the future exists, it is impossible to have a future exist wherein a time traveller destroys it in the past. That particular series of events just never happened.



**In a nutshell: Using GR, you can show that one man's past is another man's future. If you slice it just so, the two events can be shown to have happened simultaneously in spacetime.

so what you're saying is that ultimately... we'll never have any factual evidence of this?! and all of this is just going to be theories forever, since if we are destroyed we never existed anyway? and no other universes/world parallel with us or not.. would have ever known of us since we were destroyed and therefore did not exist in "time".? doesn't sound very plausible to me... although it does make 100% sense. so then this paradox WOULD be created only in our mind... if all of this NEVER really happens... so are we then... crazy? Maybe this paradox is so much that it doesn't really exist? and it is just a figment of our imagination, and wishful thinking to be able to go back in time and into the future. :) thanks for stuff guys.

 

[TheUnknown]

No. We know that a time traveller will/did not destroy this universe: it exists.

Brian Greene's book 'Fabric of the Cosmos' shows how time can be seen as an illusion. That both past and future already exist**; it is merely our limited perception that we view time as "passing". Since the future exists, it is impossible to have a future exist wherein a time traveller destroys it in the past. That particular series of events just never happened.



**In a nutshell: Using GR, you can show that one man's past is another man's future. If you slice it just so, the two events can be shown to have happened simultaneously in spacetime.

you also stated that, if our universe was destroyed then we never existed.. i have a question... if the time traveler that comes to destroy our world ... let's say world... say he brings a nuclear device with him.. with enough explosives to destroy that world.. sets it on a timer... and then leaves, and takes someone from that universe with him... then what? he saw this world before it was destroyed... so what I'm saying is, it did exist. it was not lost in time, and did not dissapear, and there would be a survivor to tell of this. unless we go by another theory saying that there is only one worldline, and once the nuclear device goes off, they cannot return to any world... and they are stuck in time, traveling inside a black whole until he passes away... or does he immediatly die as well? since his "twin" would be on that world and die when the nuke goes off? and what happens to the man he took with him... whose universe and world never existed? to many flaws. the destroyed universes theory still does not win over any kind of credibility with me :-/ i do believe in time travel... i want to see it happen... but i am looking for a theory on time travel that doesn't come to any dead ends. One dead end, is enough. Or here's another view, say.. since the explanation i was given earlier about this "destroying universes by time travel theory" that's what i'll refer to it as from now on... :P the information i was given about it, was that if you go back in time and tell your brother he will eat 2 eggs... and he does.. then all the universes where he doesn't are destroyed? which still makes absolutely no sense.. then we are limiting our time travel window every time we go back into the past by destroying universes with every action we make(makes no sense to me... seems eventually we'd all be destroyed, and then why would we be here today if the universe is omnipresent and we destroy ourselevs through time travel?)... also by stating this.. this theory is suggesting that the universe is not infinite.. and in fact it is finite.. example.. if there are 100 universes, and you go back in time, and in 50 universes your brother does eat the 2 eggs, and in the other he doesn't... so 50 universes will dissapear... so say you do this.. you go back in time, you don't tell your brother he will eat the eggs.. instead you watch him eat them.. you take him with you to travel to another universe where you tell him he will and doesn't... so how can this first brother exist still if he is supposed to be destroyed? does he disappear before your eyes? or is he still there because of the fact that you did not intervene with him eating the eggs the first time around? starting to make sense? so if you just kept going back in time and taking a your same brother from different times, and continued to experiment with him eating and not eating eggs.. and taking him with you each time to other wordlines, you'd eventually destroy the whole universe through these actions? i hardly think so... thanks guys, just discussing this here has probably amounted to 3 months worth of study. I'd really like the discussions to continue if you guys would please :) i enjoy this very much, thanks guys.

 

[TheUnknown]

? pardon? what does science have to do with something called free will? What is this thing you call free will anyway?


How can someone else be you, unless they really are you, and you them?


that's the whole idea of parallel universes, that different things can happen given the same starting conditions


free will, what's that again?

MF

this is what I'm trying to tell everyone about this multiple world theory, and this other theory which states that universes are destroyed by going back in time... "that different things can happen given the same starting"... the start wasn't 20 years ago.. it was billions... who's to say we survived or didn't survive the ice ages in every worldline, and that mankind even exists? or for those of you who believe in evolution... that we ever evolved correctly? imagine going back in time to a similar Earth with strange beings. who's to say any of us exist in any other multiple world line? everyone i talk to about this always assumes that there are parallel universes with exact replicas of us, just making different decisions... which is a paradox in itself... if we make different decisions... then why couldn't we make the different decision to mate with a different male/female and the list goes on, what I'm saying is people only theorize the way THEY want it to be... and don't open their mind to the IF's and What's... which makes a good theorizer.. GREAT. there are an infinite number of decisions you can choose throughout the existence of human kind that would forever change the world as we knowit ... lwhether it be small... or big decisions. or then again.. maybe the multiple world theory is true.. and my vision of it is correct.(also in multiple universes, why are we so generous to overlook if the Earth would ever even be placed perfectly in the position it's in now to support life?)

 

[TheUnknown]

you guys might like this one.. let's put an extremely fascinating twist on this... going back in time actually results in going into the "future" of our world... but the past's present... since we now understand free will, who's to say an einstein like person would not have been born or came about 1,000 years before ours, and that worldline is technologically 1,000 years more advanced? then this past wordline we are visiting now gives us insite into future technologies etc... so we now open up the past and the future by time traveling into the "past" only... neat huh? the universe is omnipresent with many different outcomes, this is very possible. What i am trying to prove here is we can't use "wishful thinking" theories to use to go by for time traveling information. We can't make the assumption that WE are LIVING in other universes parallel to ours... we have the will to make different choices... BUT since you HAVE to keep the theory alive, you have to say that for some reason we cannot make the DECISION to kill someone in another wordline... whereas their family tree would discontinue, and if they went back in time they would not exist in that worldline, or that our parents could NOT (this is a choice they can make, why deny them it just to fit the specifications of the theory? it's beyond all logic and reasoning, and even physics) get together with smeone else, and we don't exist. why does it seem so hard to accept for a lot of hardcore time traveler fanatics? I swear i think i am going to write a book on this, i think by proving every fault of every theory that is out there, i will in the end be able to put all working parts of these theories together, and have one final and correct solution. Time travel will and does exist! :)

 

[moving finger]

Moving Finger -
agreed to all. Still QM is (at least) strange, and time travel is not shown to be possible.

I'm sorry, but in generally accepted solutions to Einstein's equations time travel IS shown to be very possible.

MF

 

[moving finger]

I get it. I get it!


All the thought experiements about traveling to the past and setting up a paradox make the same assumption; they make the assumption that the past is open, i.e. that it has not happened yet, i.e. that it is still possible to shoot one's mom.

The past is not the future. It has happened. We know that you will not return to the past and shoot your mother because it did not happen. (That's the one advantage of the past, that we know what (will have) actually transpired).

This plays right into the concept that time is an illusion, that past and future are merely the myopia of living creatures. If the past present and future have already been painted on the canvas (this is the "block time" referred to), then there is, simply put, no picture of our universe that was painted where a paradox occurred.

Does this mean we do not have free will? Maybe. It doesn't require the preposterous notion that some 'thing' will prevent you from pulling the trigger, it just means that the universe you are attempting to describe wherein those events occurred, is simply not in existence. You did not shoot your mother. Period.

Congratulations, Dave, this is the SCH hypothesis that we have been discussing in this thread at length (basically : that only self-consistent histories are allowed). If we assume a deterministic universe then this leads to the Block Time picture, and all of our future is just as fixed and determined as is our past, and no time traveller can "change" the past any more than we can "change" the future. It is not that "the past is not the future" as you suggest, it is that both past and future are fixed and determined, both past and future "have happened" in the sense that they are both out there, simply waiting to be discovered.

There are a couple of problems we need to address with this picture however :

1 : If we allow time-travel then in theory you could travel back to your own past and tell yourself in detail what you will have for breakfast tomorrow. Armed with such knowledge, are you seriously telling me that you would accept that your tomorrow's breakfast menu is now fixed, and there is absolutely nothing you can do now to ensure that the prediction turns out to be false? If you believe in the possibility of time travel and in the SCH hypothesis then you must answer "yes" to this question. I answer "no" to this question, not because I believe in something called "free will" or anything airy-fairy like that (what is free will anyway?), but because I believe the absurd situation that presents itself suggests to me that there is something fundamentally flawed with the suggested experiment, and the flaw is probably the possibility of time travel in the first place.

2 : Time travel and the Block Time picture also imply that the universe must be super-deterministic with no possibility of any uncertainty in anything, even at a quantum level (the perfect consistency of spacetime would require a super-deterministic universe). Hence, QM is deterministic (Hidden Variables?) and not indeterministic as the conventional interpretation would have us believe.

MF

 

[moving finger]

free will... the ability to make your own decisions?

The decisions you make are based on the information and experiences in your brain (if you like, based on the software you have been "programmed" with). A computer also makes decisions based on the software that it has been programmed with.
Does this mean that by your definition a computer has free will?
If not, why not?

Sorry, but I think there is something very slippery about trying to define free will, and then to prove that humans act freely...

if you believe in time travel you must believe in free will... because you have the free will to go back in time and mess with someone and they have thr free will to agree with you, or not agree with you, and the list goes on... when thinking about time travel you MUST incorporate free will, or certainly the universe will end, to many contradicting factors with no free will.. so by my studies over the last 6 months I've come to the conclusion of many things, that is one of them... about warning someone if they do not exist... that was my point! :) if you decide to time travel and warn someone of something.. how do you know if their parents got together and successfuly had you, or the parents of their parents? or their parents? and all the way back to the ice ages, can you imagine the probability of that happening? it all has an effect, if anyone thing is altered the whole world changes. again it's free will at work... you may be way more special than you think, you may be the only YOU in this universe/world/etc. also how could you go back to escape your future? how do you know your future? and if you did, and we did, don't you think we'd stop our own future from happening instead of escaping? we can never know our future with 100% accuracy... or so i believe, and if we did escape to another world where there was no time travel what would we tell them? how would we have enough room to fit all of humanity into another worldline? would humans be scattered through multiple universes or many worldlines? would we then warn every worldline of the possible catastrophes that lie ahead? see what i mean? this destruction of universes thing cannot exist... i can't find any reasonable logical explanation of it that i can't contradict.

in all of this you are assuming the past is not "fixed", that somehow the past can be changed. That would require some kind of multiple universes viewpoint (which is legitimate, I agree), but has nothing to do with "free will" (whatever that turns out to be in the end).

MF

 

[Ich]

I'm sorry, but in generally accepted solutions to Einstein's equations time travel IS shown to be very possible.

MF

Yep, and as I said, we already know that GR cannot be strictly true, because it does not match with QM. And even if we stick to GR, maybe the conditions to achieve time travel are unphysical.
Don´t get me wrong: I´m not trying to show that time travel is impossible, because I can´t. My point is that we do not KNOW yet whether it´s possible, even if it´s a solution to a theory. Only experiment can tell for sure.
And after the consequences are so mind-boggling, one rather brings to mind that maybe we´re talking about angels dancing on a pin.

 

[moving finger]

also the destruction of universes from the consequence of time travelers would not make much sense in the fact that... if you told your brother he was going to eat 2 eggs... and he didn't... then EVERY single Earth/universe... and the people in it suddenly disappear "destroy"... so the only logical possible outcome from then on... would be for him to EAT the eggs right? so now this is where you come in... travel back again, and kill him! then what? uh oh! so he dies in every other parallel universe to.. the way this theory is thought out.. is that the consequence of one worldline effects anther? i don't believe in this because it assumes that EVERY universe where he doesn't eat the eggs is DESTROYED, why?! there is still no explanation for this... therefore if I FORCE him not to eat the eggs... the universe ends? remember all the universes where he HAS to eat the eggs has been destroyed... so am i creating a new universe by making him eat eggs? i hardly think so... this is almost laughable, because that's where this theory comes to an end :-/ it can't be true because it is incomplete and lacks a lot of logic, everytime i read it, it sounds like someone who, don't get me wrong, is very brilliant... but it sounds like their wishful thinking, desperately trying to be made true, and i think i exposed a LOT of faults here to undeniably dismiss it? don't get mad at me ich... remember i am not against time travel.. i am just pro fact, and pro logic and reasoning... i want to prove time travel to be right, and i believe it can be done... but the crazy theories trying to scare people who can't analyze the theory for themselves begin thinking time travel is going to destroy the universes... it's abs... ahhem.. you see what i mean now :)

Hi Unknown

Perhaps (with respect) you could try writing a little more coherently and succinctly? I am trying to follow your ideas but I find your writing very chaotic, which makes it difficult.

I gather that you "want" to believe in time travel, but that you find some of the potential paradoxes alarming, also that you seem to favour the multiple universes idea.

I can sympathise with this, since I also find the potential paradoxes alarming. This leads me to think that either there is something fundamantally flawed with the idea of time travel in the first place, or that the solution must be in something like the multiple universes idea.

However, I advise you to drop the idea that any of this is in any way linked to something called "free will". I think you will find that is a non-starter (if only because it is notoriously difficult to agree a sensible definition of free will, and even if one can be agreed I do not see how it could further our understanding of the problem at hand).

MF

 

[moving finger]

you also stated that, if our universe was destroyed then we never existed.. i have a question... if the time traveler that comes to destroy our world ... let's say world... say he brings a nuclear device with him.. with enough explosives to destroy that world.. sets it on a timer... and then leaves, and takes someone from that universe with him... then what?

The SCH hypothesis (assuming one universe) would say this simply would not/could not happen, because it is a non-self-consistent solution.

he saw this world before it was destroyed... so what I'm saying is, it did exist. it was not lost in time, and did not dissapear, and there would be a survivor to tell of this. unless we go by another theory saying that there is only one worldline, and once the nuclear device goes off, they cannot return to any world... and they are stuck in time, traveling inside a black whole until he passes away... or does he immediatly die as well?

No, it simply could not occur as you describe it in "one world" because of the SCH hypothesis.

since his "twin" would be on that world and die when the nuke goes off? and what happens to the man he took with him... whose universe and world never existed? to many flaws. the destroyed universes theory still does not win over any kind of credibility with me :-/ i do believe in time travel... i want to see it happen... but i am looking for a theory on time travel that doesn't come to any dead ends.

Then you have it in your multiple worlds theory.

Or here's another view, say.. since the explanation i was given earlier about this "destroying universes by time travel theory" that's what i'll refer to it as from now on... :P the information i was given about it, was that if you go back in time and tell your brother he will eat 2 eggs... and he does.. then all the universes where he doesn't are destroyed?

no, its not that the universes would be destroyed, because (assuming just one world) those universes never existed in the first place. SCH simply says that the scenario you portray is not possible, the only possible world is one which is self-consistent.

which still makes absolutely no sense.. then we are limiting our time travel window every time we go back into the past by destroying universes with every action we make(makes no sense to me... seems eventually we'd all be destroyed, and then why would we be here today if the universe is omnipresent and we destroy ourselevs through time travel?)... also by stating this.. this theory is suggesting that the universe is not infinite.. and in fact it is finite.. example.. if there are 100 universes, and you go back in time, and in 50 universes your brother does eat the 2 eggs, and in the other he doesn't... so 50 universes will dissapear... so say you do this.. you go back in time, you don't tell your brother he will eat the eggs.. instead you watch him eat them.. you take him with you to travel to another universe where you tell him he will and doesn't... so how can this first brother exist still if he is supposed to be destroyed? does he disappear before your eyes? or is he still there because of the fact that you did not intervene with him eating the eggs the first time around? starting to make sense? so if you just kept going back in time and taking a your same brother from different times, and continued to experiment with him eating and not eating eggs.. and taking him with you each time to other wordlines, you'd eventually destroy the whole universe through these actions? i hardly think so... thanks guys, just discussing this here has probably amounted to 3 months worth of study. I'd really like the discussions to continue if you guys would please :) i enjoy this very much, thanks guys.

seems like you need to separate in your mind the "multiple universe" idea from the "single universe" idea.

In the multiple universe idea then (assuming time travel is possible between universes) there would be no paradoxes and universes could be created and destroyed, and there is no need for a SCH hypothesis.

In the single universe idea then (assuming time travel is possible) it seems that we need something like the SCH hypothesis to ensure the world is self-consistent and there are no paradoxes.

Try not to mix the two ideas and you will be OK.

Hope this helps,

MF

 

[moving finger]

this is what I'm trying to tell everyone about this multiple world theory, and this other theory which states that universes are destroyed by going back in time... "that different things can happen given the same starting"... the start wasn't 20 years ago.. it was billions... who's to say we survived or didn't survive the ice ages in every worldline, and that mankind even exists? or for those of you who believe in evolution... that we ever evolved correctly? imagine going back in time to a similar Earth with strange beings. who's to say any of us exist in any other multiple world line? everyone i talk to about this always assumes that there are parallel universes with exact replicas of us, just making different decisions... which is a paradox in itself... if we make different decisions... then why couldn't we make the different decision to mate with a different male/female and the list goes on, what I'm saying is people only theorize the way THEY want it to be... and don't open their mind to the IF's and What's... which makes a good theorizer.. GREAT. there are an infinite number of decisions you can choose throughout the existence of human kind that would forever change the world as we knowit ... lwhether it be small... or big decisions. or then again.. maybe the multiple world theory is true.. and my vision of it is correct.(also in multiple universes, why are we so generous to overlook if the Earth would ever even be placed perfectly in the position it's in now to support life?)

For the multiple worlds theory to work there must be an unlimited (infinite?) number of parallel worlds, not simply to cater for different human "decisions" but also to cater for every possible outcome in every quantum mechanical event (assuming that QM is not deterministic).

If time travel is allowed, it boils down to :

Either the laws of physics are not super-deterministic and there are multiple worlds to cater for the various possible outcomes and to allow non-paradoxical time-travel.

Or the laws of physics are super-deterministic (even at a quantum level) and there is only one world with one (fixed) past and future, and (to ensure no paradoxes) this must be an entirely self-consistent solution even allowing for the possibility of time-travel.

MF

 

[moving finger]

Yep, and as I said, we already know that GR cannot be strictly true, because it does not match with QM. And even if we stick to GR, maybe the conditions to achieve time travel are unphysical.
Don´t get me wrong: I´m not trying to show that time travel is impossible, because I can´t. My point is that we do not KNOW yet whether it´s possible, even if it´s a solution to a theory. Only experiment can tell for sure.
And after the consequences are so mind-boggling, one rather brings to mind that maybe we´re talking about angels dancing on a pin.

I am inclined to agree that there is something "not quite right" about the idea of time-travel within a single world (ie if we discount the multiple-worlds idea), it seems we are forced into a situation where we need something like the SCH hypothesis to ensure no paradoxes arise, but even with this hypothesis I think the possible outcomes are absurd (such as me traveling back in time and telling myself yesterday what I will have for breakfast today, and then being powerless to do anything but have what I have been told I will have). This absurdity suggests to me there is a fundamental flaw in the idea of time travel that we have yet to discover.

MF

 

[TheUnknown]

The decisions you make are based on the information and experiences in your brain (if you like, based on the software you have been "programmed" with). A computer also makes decisions based on the software that it has been programmed with.
Does this mean that by your definition a computer has free will?
If not, why not?

Sorry, but I think there is something very slippery about trying to define free will, and then to prove that humans act freely...


in all of this you are assuming the past is not "fixed", that somehow the past can be changed. That would require some kind of multiple universes viewpoint (which is legitimate, I agree), but has nothing to do with "free will" (whatever that turns out to be in the end).

MF

A computer may NEVER have "free will" because of the fact that is has already been created by us, that destroys it's whole concept of free will, because yes it IS programmed by the creator, now if you believe in God you may argue that we then.. have no free will, but religion states that God works in mysterious ways, and that we DO have Free will, although he is omnipresent and all knowing, one of many paradoxes yet to be discovered. No i do not believe we are programmed to act a certain way or do a certain thing... we have the software, but we make our own decisions, no one is clicking a mouse or hitting Enter. Humans MUST act freely for time travel to be possible. You cannot dismiss this and then come up with a theory lacking the free actions of humans, and prove it to have no paradoxes, a paradox is a problem, it is not a solution. for free will/timetravel/multi universes to be possible, there must be only one of YOU in the entire universe, and every other Earth is full of different humans or beings. i take that back.. in a sense... there may be another you since there are an infinite amount of universes, but it is not really YOU, or they are living in your current time(i don't want to believe this can happen, but i'll give it the benefit of the doubt, on a quantum multiverse scale i find it highly unlikely you'd ever run into yourself), i take that all back, there must certainly be another you if the multiverse is infinite, but it's not YOU.. if you know what I'm saying? or when you both met, since the universe is omnipresent, your minds would explode or something, how can anyone fathom that? how can YOU be talking to YOU and listening to what YOU are saying... but not knowing what YOU are going to say before you say it, even though it is YOU talking... hm. :-/ u know? different YOU brains each not knowing what the other is thinking, yet they are both YOU. can't be possible?

 

[TheUnknown]

The SCH hypothesis (assuming one universe) would say this simply would not/could not happen, because it is a non-self-consistent solution.


No, it simply could not occur as you describe it in "one world" because of the SCH hypothesis.


Then you have it in your multiple worlds theory.


no, its not that the universes would be destroyed, because (assuming just one world) those universes never existed in the first place. SCH simply says that the scenario you portray is not possible, the only possible world is one which is self-consistent.


seems like you need to separate in your mind the "multiple universe" idea from the "single universe" idea.

In the multiple universe idea then (assuming time travel is possible between universes) there would be no paradoxes and universes could be created and destroyed, and there is no need for a SCH hypothesis.

In the single universe idea then (assuming time travel is possible) it seems that we need something like the SCH hypothesis to ensure the world is self-consistent and there are no paradoxes.

Try not to mix the two ideas and you will be OK.

Hope this helps,

MF

explain to me what a "self consistent situation is?" who's to say in 20 years i decide to become a terrorist, and i am able to get my hands on time travel, and i do indeed travel back in time and the "nuclear episode" occurs exactly the way i want it to, because i believe it will destroy the universe according to your theory. Again the free actions of humans simply cannot be dismissed. I still haven't seen anything that makes me like the "dissapearing universes" theory, as i stated... if i became a terrorist, destroyed a world, took someone from that time (because i believe in this hypothesis, that it will somehow destroy the universe... this seems to easy to me and i jump at the chance to get a time travel machine and surely enough i am able to do it, and boom the whole universe as we know it doesn't exist because of my actions.) So what you are implying is that these universes simply DO NOT exist... until we go there... then they are created upon our arrival? and they disappear while leaving? still contradicts taking someone from that universe back to our time if they don't actually exist. Sorry if i am mixing ideas... like i said i am trying to assert all of these theories and hypothesis to get a clear view of what can and cannot happen, and then come up with a very reasonable theory.. i like mulitple worlds, although there is a lot of information lacking, like the free actions of humans, and the free actions of the universe as a whole, giving an infinite number of outcomes and Earth's that could or could not have been created exactly in tis place in the universe. what if we time traveled and upon coming out of the minurature black holes (supposively the source of time travel) we find ourselves in the middle of no where, and the solar system as we know it is 3,000,000,000,000 miles away from where we are today? and that any Earth in any other universe may not be 1000 years more advanced than us if we traveled back to 1970 because another "Einstein" came along before ours.

 

[TheUnknown]

For the multiple worlds theory to work there must be an unlimited (infinite?) number of parallel worlds, not simply to cater for different human "decisions" but also to cater for every possible outcome in every quantum mechanical event (assuming that QM is not deterministic).

If time travel is allowed, it boils down to :

Either the laws of physics are not super-deterministic and there are multiple worlds to cater for the various possible outcomes and to allow non-paradoxical time-travel.

Or the laws of physics are super-deterministic (even at a quantum level) and there is only one world with one (fixed) past and future, and (to ensure no paradoxes) this must be an entirely self-consistent solution even allowing for the possibility of time-travel.

MF

i agree... i want to prove time travel is possible, but sometimes the paradoxes seem not to allow it... but we have come so far in physics, we know the possibility is not to far off, and if we are able to harness it, we need some type of reasonable solution, so the first time travelers aren't going back in time thinking they do not have free will : --->the ability to act freely and change oneselves or others mind causing CERTAIN negative and positive reactions in ones self, or in others, in any circumstances in any environment or universe at any time<----.(on the basis that time travel exists, one has these free will choices inside themself while time traveling, THEY control what they do and don't do while time traveling, and that either effects the world they are currently visiting, or doesn't, and causes consequences, and rewards[action/reaction]) i think you could in a sense.. on a time travel level, relate free will to action/reaction, free will is the actions and reactions that occur because of our actions... and we do have the free will to make these actions(nuclear episode), and they need be applied to these theories in whole.

 

[TheUnknown]

i do believe as well, if we can put together a plausible theory... that has no dead ends, and can be explained to any nay sayer, or questioner, that the possibility of time travel MUST be true. Example... planet hunting... Hubble picks a star, it can see this star, the scientist can measure the "wobble effect" on the star, and therefore a planet must exist, and they have been right everytime so far, a real theory must lead to reality, right? we can see the star (time) we know it's there, now we are measuring it's wobble(possibility of existence). if there is no wobble then the travel does not exist.

 

[Ich]

I am inclined to agree that there is something "not quite right" about the idea of time-travel within a single world (ie if we discount the multiple-worlds idea), it seems we are forced into a situation where we need something like the SCH hypothesis to ensure no paradoxes arise, but even with this hypothesis I think the possible outcomes are absurd (such as me traveling back in time and telling myself yesterday what I will have for breakfast today, and then being powerless to do anything but have what I have been told I will have). This absurdity suggests to me there is a fundamental flaw in the idea of time travel that we have yet to discover.

MF

guess we have a common point. This multiverse stuff seems to be the most approproiate to handle time travel, but I don´t really like it.

 

[TheUnknown]

free will : --->the ability to act freely and change oneselves or others mind causing CERTAIN negative and positive reactions in ones self, or in others, in any circumstances in any environment or universe at any time<----.(on the basis that time travel exists, one has these free will choices inside themself while time traveling, THEY control what they do and don't do while time traveling, and that either effects the world they are currently visiting, or doesn't, and causes consequences, and rewards[action/reaction])

 

[DaveC426913]

Personally, I don't get this multiple worlds idea. The logic is backwards.

"If we can't travel back into our own time, then at least we should be able to travel to the past by traveling back into an alternate time."

See, it starts with the premise that we simply cannot travel back into our own time. Then it goes on to say "but I really *want* to believe time travel of *some* sort is possible, so I'm ging to invent an alternate way it could happen - subjectively - from my point of view."

It's inventing a phenomemon out of "whole cloth" for no reason (other than because we want fodder for stories). It doesn't resolve *anything*.

The only way this would make sense is if we *had* a working time machine, that really *did* travel to a place that looks just like our past. And we were standing around scratching our heads, and saying "How is this possible? Where are they going when they go to the past? Since our universe hasn't disappeared in a puff of illogic, perhaps they're going to an alternate history."

 

[TheUnknown]

Personally, I don't get this multiple worlds idea. The logic is backwards.

"If we can't travel back into our own time, then at least we should be able to travel to the past by traveling back into an alternate time."

See, it starts with the premise that we simply cannot travel back into our own time. Then it goes on to say "but I really *want* to believe time travel of *some* sort is possible, so I'm ging to invent an alternate way it could happen - subjectively - from my point of view."

It's inventing a phenomemon out of "whole cloth" for no reason (other than because we want fodder for stories). It doesn't resolve *anything*.

The only way this would make sense is if we *had* a working time machine, that really *did* travel to a place that looks just like our past. And we were standing around scratching our heads, and saying "How is this possible? Where are they going when they go to the past? Since our universe hasn't disappeared in a puff of illogic, perhaps they're going to an alternate history."

alternate history/alternate worldline multiverse can all be tied together.. it is not just taking an opinion and saying believe this! it's taking all these other theories and saying.. look how faulty and wrong these are, they could never happen, since we have phylosophy and we understand that humans make choices everyday, they cannot be, the only way this could be possible is by doing it this way... there are no dead ends and no paradoxes, so why can it not be true? how could we travel back into "our" own time? if you really sit and think about, it does not work, time travel of that sort is not possible, if that's the only way time travel... could work, then i guess time travel is impossible in that sense. going back to a different history would suggest the multiple world theory, and with the multiple world theory, you then get back to square 1, which says, if there is an alternate universe with people making different decisions to have different histories, then everything in that world as we know it will be different, because every single human being every single day will make a different decision than he made today, or a different thought, at least once! at the least! and that's being generous! what if john wilks booth decided not to kill lincoln? what if america never dropped it nukes and germany came to power with the first nukes? alternate history is exactly what i am suggesting, and you are saying you believe in it... but you only want it to work according to this theory(which would say that for some reason the Earth started 100 or so years ago, forgetting about everything that has occurred over the past billions of years on earth, with all the people in it now, so if you went back to 1975, all the same people are there.. but with a different history?), you only want the histories to be different, but all the same people still exist, and all the planets lined up right, and (again if you believe in evolution) and all animals evolved the same, creating the same people to die from certain animals etc. etc. you see how cimplicated and how much of an amazing anomoly it would be to actually have an exact replica of our Earth with all the same people in it, but only making decisions that change in OUR view of OUR "historical events", but somehow still has all the same people living in it,. also physics are starting to expose the travels in time... so if it's possible, and we know it can't work a certain way, then it must work another way... which would mean 1.) multi universes do exist. Or 2.) time travel is not possible, or is a figment of the imagination created by intense gravitational fields (black holes).. or you do go back in time, and everything you think you are doing is not actually happening, although all the events around you are truly unfolding... I'm trying to figure out some way that time travel may be true.. but false at the same time, more of a mental lapse created by the gravitational field, that actually takes you back to these times and allows you to visualize or something, anyway, that sounds very incomplete and ridiculous, because it is incomplete, i'll put more thought into it, and see what i can come up with. also, when we do figure time travel, and the multiverse idea is true, then surely religion will have be rethought by many athiest... how could something like this beyond our thoughts be created over and over and over and over again unless a greater power wanted it to be that way so that we COULD time travel?

 

[moving finger]

the computer will just split out complete histories, all you can do is view them. But in these histories, there may be simulated intelligent beings who learn to time travel, and a time traveler may meet another being and tell him in advance what he was going to do. So if this being asks the time traveler, "but what will prevent me from doing something different?", I'm asking you what you think the best answer to him would be if you were to imagine responding to him in your head, you can't actually tell him the answer since you are not part of the simulation.

Hi Jesse

Can we examine the simulations analogy in more detail please?

The hyperspace computer producing these simulations is presumably generating each of these simulations at random, using some kind of "starting point" or “seed” in the time-axis of 4D spacetime (it could be at the beginning of time, the end of time, or any point on the time-axis, since using Block Time and the deterministic view, we should be able to generate any particular history, past and future, given the precise spacetime coordinates for one particular point on the temporal axis of that history). Do you agree?
The computer then uses the deterministic algorithm to simply generate the full 4D spacetime history from a given starting point (seed).
I am interested in the selection process for complete histories - the process the computer uses to select and “split out” only complete (ie self-consistent) spacetimes for the hyperbeings to view.
The computer presumably selects seeds at random and generates a multitude of random spacetime histories?

Are we saying (A) that it is possible (in principle) for the computer to generate (given a particular starting seed) a spacetime history which is inconsistent and therefore incomplete? In which case the entire set of histories generated by the computer will contain both complete (consistent) and incomplete (inconsistent) histories, and the computer then presumably retrospectively discards the incomplete histories?

Or are we saying (B) that the computer will only use seeds that will always generate only complete and consistent spacetime histories?

If (A), then there is some point in the “hypertime” of the computer when each incomplete history “exists”, prior to being discarded. Presumably, the simulated beings within this incomplete history “experience” that existence, just as much as the simulated beings within a complete history. In which case, both complete and incomplete histories, at some point in hypertime, give rise to conditions whereby 4D simulated beings experience existence. This being the case, it is clearly possible that our present universe could be one with either a complete or an incomplete history (if incomplete, we simply have not yet reached the point of inconsistency which renders our spacetime incomplete).

If (B), then this implies there must be some kind of preferential “pre-selection” of seeds that will produce ONLY complete spacetimes, ie seeds that will produce incomplete spacetimes are somehow eliminated from the batch of seeds used for the simulations BEFORE they are used to produce an incomplete history. But in this case we must ask the question – what is the selection process? How are seeds pre-selected to “weed out” the ones that will lead to incomplete spacetimes (it cannot be by actually RUNNING the simulation and generating the relevant spacetime, since this leads us back to (A))?

Interesting questions……which seem to suggest that the “self-consistent histories” solution is perhaps not such a complete and neat solution after all….

MF

 

[moving finger]

explain to me what a "self consistent situation is?"

a self-consistent solution is only relevant to the single universe scenario. basically, any timeline which creates a paradox (such as me going back in time and killing my mother before I am born) would be non-self-consistent (ie could not result in a single coherent and complete 4D spacetime within a single universe, because it contains the paradox that i exist and yet my mother died before i was born).

who's to say in 20 years i decide to become a terrorist, and i am able to get my hands on time travel, and i do indeed travel back in time and the "nuclear episode" occurs exactly the way i want it to, because i believe it will destroy the universe according to your theory. Again the free actions of humans simply cannot be dismissed. I still haven't seen anything that makes me like the "dissapearing universes" theory, as i stated... if i became a terrorist, destroyed a world,

again, please be clear about whether you are talking about the single universe scenario, or the multiple universes scenarion.

If multiple, then self-consistent solutions are not necessary or relevant.

If single, then how can you "exist" if at the same time you have destroyed your past (this is the non-self-consistent timeline).

took someone from that time (because i believe in this hypothesis, that it will somehow destroy the universe... this seems to easy to me and i jump at the chance to get a time travel machine and surely enough i am able to do it, and boom the whole universe as we know it doesn't exist because of my actions.)

Again - if single universe you have created a paradox, a non-self-consistent solution.

If multiple universes, no problem.

So what you are implying is that these universes simply DO NOT exist... until we go there... then they are created upon our arrival? and they disappear while leaving? still contradicts taking someone from that universe back to our time if they don't actually exist.

No, I never said that. If multiple universes, then they DO all exist, every one of them, in parallel with our own, all equivalent.

Sorry if i am mixing ideas... like i said i am trying to assert all of these theories and hypothesis to get a clear view of what can and cannot happen, and then come up with a very reasonable theory.. i like mulitple worlds, although there is a lot of information lacking, like the free actions of humans, and the free actions of the universe as a whole, giving an infinite number of outcomes and Earth's that could or could not have been created exactly in tis place in the universe.

There you go again talking of "free" actions. Please define what is a "free action"?

what if we time traveled and upon coming out of the minurature black holes (supposively the source of time travel)

nope. Black holes are not necessary.

we find ourselves in the middle of no where, and the solar system as we know it is 3,000,000,000,000 miles away from where we are today? and that any Earth in any other universe may not be 1000 years more advanced than us if we traveled back to 1970 because another "Einstein" came along before ours.

yes... and your point is?

MF

 

[moving finger]

A computer may NEVER have "free will" because of the fact that is has already been created by us, that destroys it's whole concept of free will, because yes it IS programmed by the creator, now if you believe in God you may argue that we then.. have no free will, but religion states that God works in mysterious ways, and that we DO have Free will, although he is omnipresent and all knowing, one of many paradoxes yet to be discovered.

But none of this follows from your definition of free will!

Are you saying that nothing "created" by a human being can ever have free will? How are human beings created... by other human beings!

Why does the fact that something has been created "destroy its whole concept of free will"? There is nothing that leads to this conclusion in your definition of free will.

There is also nothing in your definition that says free will can be endowed on a creature only by God.

Please can you re-define free will such that it is consistent with what you have said?

No i do not believe we are programmed to act a certain way or do a certain thing... we have the software, but we make our own decisions, no one is clicking a mouse or hitting Enter.

A machine can be designed to make decisions without any outside observer clicking a mouse or hitting "Enter", does this make it free?

Humans MUST act freely for time travel to be possible.

why?

You cannot dismiss this and then come up with a theory lacking the free actions of humans, and prove it to have no paradoxes, a paradox is a problem, it is not a solution. for free will/timetravel/multi universes to be possible, there must be only one of YOU in the entire universe, and every other Earth is full of different humans or beings.

what does this have to do with free will?

i take that back.. in a sense... there may be another you since there are an infinite amount of universes, but it is not really YOU, or they are living in your current time(i don't want to believe this can happen, but i'll give it the benefit of the doubt, on a quantum multiverse scale i find it highly unlikely you'd ever run into yourself), i take that all back, there must certainly be another you if the multiverse is infinite, but it's not YOU.. if you know what I'm saying? or when you both met, since the universe is omnipresent, your minds would explode or something, how can anyone fathom that? how can YOU be talking to YOU and listening to what YOU are saying... but not knowing what YOU are going to say before you say it, even though it is YOU talking... hm. :-/ u know? different YOU brains each not knowing what the other is thinking, yet they are both YOU. can't be possible?

There is only one of you. Even someone who is almost identical to you in another universe is still not you. But this has absolutely nothing to do with the existence or non-existence of free will (which we cannot debate yet because we still don't have a definition that we are happy with)

MF