Is it conceivably possible to travel back in time to kill your grandfather and thus stop your birth ever happening?
How do you get around this paradox?

I'll post my own ideas on it soon enough. I'm interested to see if others come to the same conclusion as me without having seen my own view first.

Throne777

This reminds me of some crappy song from an even crappier movie which is characterized by the line "I'm my own grandpa!" In all seriousness, though, doing that would change nothing. It would merely spawn a parallel universe where that event didn't happen, or else an alternate reality where not only did that event not happen, but many others as well (basic consolidation to create a common outcome).

divergent time line caused by an event that occured in the one you back to that is not your own past but an alternate past caused by you going to it.

this paradox now-a-days is gone around using the ole, you can't travel into your own past as you are the product of the unique series of events that occured, therefore you can only travel into a past that is currently going on (which goes into this whole other area of pre-destination or rather quasi pre-destination of incredibly simular yet moving at different speeds parallel realities.

there fore in simplest terms if you go back in time the man you kill isn't your grandfather but his counterpart in that universe meaning that you wont have a counter part in that universe when its time line moves to the same time as the point you came from in your own time line.

Exactly, if you travel back in time, you'll be outside your current timeline anyway, so you should not be affected by anything you do in that period.

There's no paradox with a continuous time stream. The very fact that you are alive to go back in time means that what-ever you might plan you cannot kill your biological ancestor of any generation.

So if you go back in time then you wont kill anyone who is in direct line to your birth.

The current theories of time travel based on quantum physics support the conclusions by Alaras, Rhuen, and Pier. There is no one continuous timeline, but several that are created even at microscopic levels. Our perception of space and time is very limited to our own position within our one personal space/time.

On a side note, theoretically to travel back in time you need a fixed point in space/time to travel back to, a time machine. Hence, you wouldn't be able to travel further back in time than when the time machine was invented. Unless a person was born after the time machine was invented, any potential ancestor of his in any timeline would still be pretty safe from the implications of this paradox.

Fascintating... And just how would you navigate a closed timelike curve? What to the pseudo scientific nincompoops who try to postulate time travel from the most badly misunderstood theory in the history of science have to say about that?

A: Fish.

real answer:
its a matter of preference. Multi-universe time travel is easier to use as it has no real paradox problems, unless you end up in one of those that after traveling into the past you end up stuck in that reality when going to the future (into its future rather than back into your present) but you are still an outsider to that universe.

its easier to work with than a Dr. Who or Back to the Future time travel system as those are so full of paradoxes that you either have to say what WilV said with the whole you are the product of your own changes to the past as well so have no memory of what occured with out those changes (history that can rewrite its self) (Dr.Who), or simply erases elements that are paradoxes like in (Back to the Future).

It's inspiring to see such fastidious adherence to the scientific method, but I don't think we'll be seeing a time machine built into a Delorian or a Police Phone Box any time soon...

As much as anything else, Delorian is now a convicted criminal, his car design no longer in production, and Police Phone Boxes have been obviated in favour of hand held radio sets.

Another thing that has been obviated for some time, and that was never taken terribly seriously to begin with outside the annals of science fiction, is the Hugh Everett interpretation of QM that you mentioned.

Time travel outside of science fiction and into real physics, is like dragons outside of fantasy into biology.

even if it can be made to seem possible, its still not.

I would imagine that removing a person from their own timeline and into another they would treated like a pile of exotic particles and either be rejected from space and time in that timeline or suffer cascade failure and be erased. the forces alone to allow a person to travel out of their own universe alone might be enough to kill the person no matter what.

move from one universe and into another as smoke.

then again time travel isn't treated serious in science that I am aware of, we can't even really state yet that time has a material existance, that would be required to be manipulated.

what happens if 2 timelines intersect? sort of like a mid second collision.lol everything existign within itself for a split second and exploding every molecule of our being before collapsing it back into the space that the parallel matter no longer encompases. lol and that's not even taking into efect the massive gravity alterations.

That is why they are called PARALLEL universes and not PERPINDICULAR universes.

they don't exist in the sams space time. So even if by some ultra-dimensionally pathways deal timelines were to intersect rather than flow apart I'd say just like with alternative dimensions they wouldn't even be aware of it.

a physical universe example, lasers (beams of light) have particles yet when they cross each other they don't affect each other, as in don't cancel or interfere with each other's paths.

However the exact shape or nature of a universe is unknown, and if realities are paralel then they actually exist together in a way that can't be explained in physical terms "parallel and alternate" are really the best words we can use, but the idea is that they actually are not seperate completly only existing apart despite being the same thing.

occupy the same space, but not the same time so can't actually touch each other. the basic idea being that no two are perfectly in synce like at the very least occuying time maybe only nano-seconds apart.

to be honest though, time and higher dimensions are things so far outside our sphere of influence and knowledge that we don't have terms for them yet (as in terms for how they function).
Just as a thousand years ago we didn't have terms for computer programs, or celestial distances. go back far enough and we didn't even have terms for zero, let alone things like atoms or cells.

for us now, it would be like trying to explaine nuclear engineering to a monkey.

I cannot believe that you had the audacity to accuse me of being unempirical, and you are now spouting this metaphysical garbage!



I think you are confusing the Everett Interpretation of QM with Data's positronic brain in Star Trek TNG my friend. I don't recall ever hearing the term "cascade failure" used in reference to anything other than a Noonyan Soong type android, or of any way that particles can be erased from existance. Even antimatter anihilation doesn't do that...

the Everett Interpretation of Quantum Mechanics, if I am reading it rights, seems to mix and match the two concepts of parallel timelines and parallel dimensions.

which I have always viewed as two seperate things.

a parallel time line would be like a split in a branch, while a parallel dimension is a seperate fiber in the same branch.

its like an idea just being born.

on a subject that can't be experimented on. so it just comes to be an educated person's opinion and preference on the concept of time travel and alternate worlds.
as it can't be experimented on, you can't run experiments to test if event A will cause event B unless to exist in a parallel universe rather than the control universe where event A doesn't occure. You can postulate but not experiment. as no means exists to even prove alternate timelines and dimensions physically exist, how they are related to each other, if they are even connected in anyway that allows for any manner of travel or influence between them, and if time can even be manipulated.



you are erased, as in vaperized. particles displaced and no longer forming the same shape as they had before. as in matter meets anti-matter reduced to energy.

when I said cascade failure I meant that the person's structure being foreign to that universe would break down over time as the host universe rejects them. like foreign object in the body.
(which is from the Living Universe idea about reality travel).

or that the laws of physics or the strain from dimension hopping could have a breakdown effect on the body of someone or something traveling between them. As in in Dimension A your body was adapted to live in a reality where the pull of Strong Force and the speed of electrons was slightly different than that of Dimension B. your body being part of Dimension A can't adjust to the new physics imposed on it, and reacts negativly to it causing it to breakdown.

There is nothing we have learned in the history of physics that would lead one to believe or disbelieve that allegation.



Antimatter and matter do not "reduce" anything. The amount of mass-energy before and after the collision are precisely equal, there is no delta whatsoever... Angular momentum and electric charge are also precisely conserved in the process...

On the other point, your assertions about dimensions A and B are baseless...



I see... And that viewpoint is based on what? Let's see your calculations and empirical data.

An action does not effect time....Actions occur within space/time.

Whether your coin lands heads or tails it will land in the same universe it started off in because you cannot simply generate an entire new universe from a simple action.

An event that happened in the past stays happened...Even if elements of the future had something to do with that occurrence to begin with. You cannot just endlessly overwrite the past even if it's popular in terrible SciFi to do so.

reduced to, as in changed into. a body is reduced to ashes, ect...get it.

on another note WTF!?

are you actually takeing this topic seriously?

baseless, no shit, you don't say.

oh my various gods. who would have thought an imaginary concept like time travel would have baseless assertions.

I base alternatie timelines and dimensions on preference. Like alterative timeline being a universe with all the same basic things like people (a whole other universe with its own sub-dimensions).
and another dimension as another layer within the same universe.

my empircal evidence: because I bloody like it better that way.

sheesh.

seriousness on a topic about something our monkey brains can't even fathom in any real way.

I already said it, its all about preferences and what we like better on this topic.
an educated man's guesses and preferences are no better than movie makers on this. its about who can sound smarter makes it who is listened to about things like alternate universes and time travel.

my empircal evidence: time travel doesn't exist outside of science fiction, ergo I use science fiction as the source.
any real world scientists talking about it are just stateing their preferences about it as they can't actually test it.

Don't be ridiculous. I am incredulous that other people are!



Oh, but I do.



Then you're a fool.



Then let us hope that no one ever has a lapse of judgement and puts you in a position of authority in some kind in any field that requires critical thinking.



We aren't monkey's, we're apes. Monkeys have a pronounced tail.



Try harder!



That is a very obvious oxymoron, and not really worthy of you, or any other thinking person. I can see you are a smart man, so why not use that brain of yours?

the thing is I treat time travel and multi-world concepts as fantasy.

now the alternate timeline and alternate dimensions things. I wouldn't think is too far off to seperate them as two different things, or rather smaller or greater exagerations of a simular concept.

now for most things I would state the need for empirical evidence.
a close study, the thing is though I don't use that for time travel or sub-space or alternate timelines not because I feel their not needed, but because I feel they can't be used in this case.

empircal evidence requires the ability to test and/or observe something. but we have no means to do so with either time travel or other space/time continiums or subdimensional layers of our own universe.

so as such I am left with nothing to base anything on than the preferences made by people using pseudo-science or straight out fantasy as their basis on the subject.

therefore I until someone comes forth with a means to actually observe or manipulate these things to prove their existance I am left with only treating them as science fiction.

hence my use of science fiction quasi/pseudo scientific terms.

for instance the use of "cascade failure" in regards to timeline jumping came from Star Gate SG-1 in the second Quantum Mirror episode where an alternate Carter was at risk of dieng for somereason because the main series Carter was also present, causing their universe to reject the duplicate for some reason.

this doesn't make any sense to me, but was the only source for the concept.

on my main idea about time travel and other dimensions (the versions I use for my own fantasy, see my first post in this thread) every thing sense has been reiterations from shows and movies like Star Gate, Dr. Who, Back to the Future, ect...

My views on this are very humble. I don't know a lot and cannot explain them fully due to the same lack of understanding that others have. Please forgive this. But i consider that if the universe and different points of time ARE connected and indeed as like one whole, then perhaps such a paradox is not really possible. Also that the question might need to be seen with different realities.

I consider that if you really were to try to do this, you would not be "allowed" ... as in you would not ever get to that point. I bet this seems as if I am asserting the existence of a diety, but I am really not. Merely an existence where the past and future are connected heavily. If you would really do this, again, you never come to that point. I know this seems rather fucked up and I am just sort of stabbing in the dark here, but it makes more sense to me than other things.

Also, what is you? And who is your grandfather? This might seem a ridiculous question but it reallly isn't. It is actually quite good. It is very relevant if you hink you will actually ever be "allowed" to make it to that point.

That's the crux of the matter...

I'm talking about mathematics, not metaphysics. Parallel lines never intersect. If they did, they'd be called intersecting lines. I'm merely applying an identical concept to universes.

which is the crux as you say.

I could reiterate every single type and variation there of of time travel presented in all manner of shows and books from "Time Lords" to "Ben Ten ALien force", from "Star Trek" to "Star Gate" and beyond.

from various forms of over-writing timelines, parallel time lines, alternate pasts and futures vs alternate realities, and dimensions all together.

but when it all comes to its end, the result is every single one was fiction and made up by people bouncing and baseing their ideas off of each other to create a complex mythos for the concept.

And that application is metaphysical...

Or am I wrong?

Alright then empiracist, now prove that it can be applied to universes.

Watch the movie "Twelve Monkeys"

and you'll get it all.

If you go back in time and if you alter the past somehow the things you do will make the present the way it is now.
"And so it is written in the past that the man will come from the future to make us this present."- kind of thing.

Oh yeah! And the movie "Time Line" a great one too!

I do get it all... I studied Kaluza Klein derivatives, Relativity, QM and QCD for years when I was naive enough to believe that a GUT was round the corner and not above the glass ceiling. That is why I have so little patience for this kind of fervant misrepresentation of these theories...

You show a lott of emotion, but you lack of piont.

I had assumed the point would have been obvious, but then as a great man once said, many people can't see the splinter in another persons eye for the piece of two by four in theirs...

I felt little or no emotion at the time of writing that post. I simply deplore intellect without discipline. I would never dream of pontificating on a subject without studying it first, and I can't help thinking that if I could convince others to follow that ethos, the world might not be in such a sad state at the moment...

I have noticed a lamentable disregard for truth displayed by my fellow man, and it does make me feel weary from time to time...

I'll leave to your circles...

I don't even know what that's supposed to mean, but good day to you...

Just give me a couple of days to obtain the mathematical proofs. I forgot where I saw them and it'll take me a bit to find the link.

I don't want to see Kaluza Klein based maths, I am already familiar with it. I want to see peer reviewed empirical data that has been ratified by experiment, not pseudo scientific mathematical flim flammery...

The kinds of math theory you are talking about is riddled with infinities, arbitrary constants and fudged solutions. It is not worth the paper it is written on and is merely an extrapolation of tensors into dimensions that may or may not, almost certainly the latter, exist.

If you have a theory that will allow us to travel through time, then for God's sakes get it published and collect your nobel prize!

The prerequisites won't exist for at least another 1000 years, and it'll take another 30-40 years after that for a crude and inefficient prototype to be made.

RATFLMFAO!!!!!

I believe you meant to type ROTFLMFAO. You misspelled your own hysterics.

I was just indicating that I enjoyed your gag... I wasn't too worried about precision in the spelling...

i know topic has probably started to die but just in theory couldnt you possible just get an anchor?
something that was existant in the past with a portable time traveling device to travel back, i know it's a bit off topic but i was just wondering to see who else would go along with what im thinking.

Let’s forget about time machines, laws of quantum mechanics, and all your other scientific theories that don’t really apply due to practical application, and for just a moment think about this from a logical perspective.

If you travelled back in time and killed your own grandfather, then you would be negating the possibility of your own conception, which in turn would mean that you never existed and therefore could never have traveled back to kill your grandfather in the first place. Of course if you didn’t travel back in time then you would exist and therefore could travel back in time to kill your grandfather. It’s a circular conundrum… The fact that it could be possible to travel back in time to kill your grandfather means that by doing so makes the act impossible because doing so negates the initial decision to do so in the first place.

So I'm voting "no", I don't think it would be possible...

this scenario was mentioned on "The Science of Star Gate", as why they went with the alternate reality bit for time travel, alternate past to create alternate presents, even though on the show they kept traveling back into the altered version of the present after going into the past.

If you could alter the past to create an alternate future it would mean that the timeline in neither fixed nor linear, which would create all kinds of problems. I think I’m going to go ahead and stick with the fixed linear notion, many less headaches come from that direction…

All go back and actually read my post. It's not based on wishful thinking and pseudo-science but on simple logic. As logic has been shown to work I thus have the only really solid defensible position on this.

Your first post missed the theme of the paradox entirely Vore, it’s not about which universe the coin will land in, but whether the coin was ever flipped to begin with. The paradox isn’t necessarily about the decision being made, but whether it’s possible to make the decision due to the constraints of a linear timeline.

Nuh uh *snaps fingers* You missed my point!

The coin in the present is the coin in the past, there is no past and present. It's human conceptual experience that there is a past.

I'm saying that the paradox is not a problem because it simply cannot occur. Things can have relative speeds of causality (rates of time) as the theory of relativity and genuine experiments using atomic clocks on jets have shown but time is still linear.

Relativity makes it possible for an explorer travelling at near light speed to get to another galaxy in a certain amount of time then return to find everyone he has ever known is dead...This is an extreme example that supposedly could occur were near light speed travel possible. What would not be possible is for him to arrive before he set off. Time (Space/time) can be stretched, elongated and stunted by extreme forces but never broken. Not unless you think black holes are tears. I do not because there is no reason to think so.

If time is linear, which you agreed that it was, then in order for there to be a present there must be a past “or starting point” from which time began. Whether it is merely conceptual through the human experience or a force that has yet to be quantified in physicality, time, in actuality, does have a past as well as a present; otherwise there wouldn’t be a way to measure time in a linear manner…

If you are trying to say that it’s impossible for something to exist in two different “times” at the same time, then I will agree with you, but that’s not what we are really talking about. If one was to travel back in time to kill their grandfather then at that point in time which they left from they would cease to exist and in turn exist in the point in time they went to. We are not talking about creating separate states of existence, but rather altering the state of existence which we currently perceive.

Nuh uh *snaps fingers* You missed my point! ~ Right back at ya!!
If you will notice at the end of my original post I am agreeing with you, I don't think it would be possible either...

You still missed the point.

Time being linear doesn't mean you leave a snail trail of causality behind you. The chair you broke yesterday isn't left behind unbroken the day before...It's right there broken on your floor today. The speed at which the event may seem to have occurred might alter under extremis but for all parties the chair is completely in one continuous yet infinitely tiny indivisible 'moment' we call 'now' (nobody has ever said the word 'now' and said it fast enough for it not to have been far too late).

The past is your present memory and the effects of presents now past that don't otherwise exist but for the effects they leave behind. There is no vast accumulation of Victorian, Stone Age and Neolithic Earths etc...In some temporal warehouse waiting to be revisited...Travelling to the future is merely breaking a mirror instead of waiting for it to fall apart...Travelling to the past is putting that mirror back together exactly as it once was by applying a myriad near infinite number of forces in reverse. Or as the Doctor said to the man with a vacuum cleaner on his penis 'It don't work like that.'

The paradox isn’t about whether there is an existence in the past to travel to, it is saying that there is “regardless of whether it’s possible or not” and taking that information we form a conclusion. It’s not about whether you can travel back to a different time “it’s saying that you can, that time exists and you have the ability to go there, and once you are there you exist in that point in time”.

I get where you are coming form but that’s not the point, the paradox has constraints, those constraints may bend the universe as we know it but that’s not the point. The question isn’t about whether it’s possible to travel in time but taking for granted that you have the ability.

The past time one I know that many use today for stories is that the past is not your past because that no longer exists.

traveling through time instead is traveling to other universes, no past event then is 100% the same as what your universe experienced.

Its like a river flowing over the river bed, the bends and turns cause the drops in the river to share simular paths but never the same path twice, those drops closist together or flowing along near each other share simular histories.

traveling back in time would then be flying out of the river going back to the bend or stray rock in the bed that marks the event you want to vist and then dropping back in, however the past before that universe may have followed other events than your's did (other turns and points and just happened to flow to the point that is simular to what your universe was)

for example that bend and distance from the shore and distance above the river bed represents WWII, however due to events before that bend for that drop you dropped into instead of Hitler being in charge of Germany Johan Strauss was instead and in its future (which is chaotic twists and turns just like yours where events are decided by internal momentum (free will events guiding the drop) and the broad archaetype structure of the river design. So while you may have gone into what basically looks like your past, its not, and it wont have the same future (your present) even if it follows the same close path.

Except that going to an identical universe makes no sense. A universe that exists and is different solely because you tied a shoe tighter one morning? Nope.

OK Aaron...What you're saying is...If you ignore the fact that it's impossible...Would it be possible?

....

I have stated several times now that I don't think it's possible, but not for the reasons you gave...

~cheers~ You made me laugh out loud with that one!