NationStates Jolt Archive

*tells the two doctors to leave*

okay, so heres a brain twister for you.

If you go back in time to kill your own grandfather, what happens? Does nature intervine? Does the gun misfire? Do simply keep slipping in and out of existence due to the fact that, after the bullet exits your grandfather, you cease to exist, thus making the bullet never get fired, thus making your grandfather not die, thus bringing you back into existence, thus restarting the cycle?

hmmmm? :headbang:

I think my brain just exploded.

Actually, nothing really happens. You grow up knowing someone killed your grandfather, are horrified to discover it is you, and for some reason end up doing it anyway. Thus, the cycle is completed.

This is why time travel is impossible. I almost think that the impossibility of time travel is a strong argument for either the existence of God or the existence of a natural order that knows what it's doing.

Actually, nothing really happens. You grow up knowing someone killed your grandfather, are horrified to discover it is you, and for some reason end up doing it anyway. Thus, the cycle is completed.

What if your father hasn't been born yet?

What if your father hasn't been born yet?then u r an idiot and have some problems cause u arent born. So wait till after ur father is married so he at least knows he probably going to have u. :)

Maybe your grandfather isn't really your grandfather. You kill your grandfather and some random guy takes up his identity. If it wasn't meant to happen, it wouldn't.

or if you bileave thats stuff about "multiple worlds theory" then you'd just have shot your grandfather in anothed dimension and he'd still be alive in this one. There's somthin thats always bothered me about this question and I've just figured it out "if you could go back in time WHY WOULD YOU SHOOT YOUR GRANDFATHER IN THE FIST PLACE!?"

*tells the two doctors to leave*

okay, so heres a brain twister for you.

If you go back in time to kill your own grandfather, what happens? Does nature intervine? Does the gun misfire? Do simply keep slipping in and out of existence due to the fact that, after the bullet exits your grandfather, you cease to exist, thus making the bullet never get fired, thus making your grandfather not die, thus bringing you back into existence, thus restarting the cycle?

hmmmm? :headbang:

The situation itself is impossible, you can't prevent your birth. If you go back in time and kill who you think was your grandfather then it will turn out to have been someone else. If your potential grandfather goes and gets killed before making your father then it won't be you that goes back and kills him.

Think of it like that whole thing with the different possibilities making different dimensions. The "trousers of time." All that happens is that some of the "legs" are removed if your grandfather gets killed, but the only legs that can still remain are those that lead to you being born anyway or someone else killing your grandfather. If you go and kill your actual grandfather then the "legs" that lead to you being born collapse and only those "legs" that are different enough not to be a paradox remain. In essense, while time travel is not logically impossible, traveling to a past in which you can kill your progenitors is logically incoherent. Traveling to that past causes it not to exist so when you get there it turns out that your grandmother got pregnant by someone else or something like that.

There's somthin thats always bothered me about this question and I've just figured it out "if you could go back in time WHY WOULD YOU SHOOT YOUR GRANDFATHER IN THE FIST PLACE!?"

You could accidentaly hit him with a car or something. Like on Futurama, the delivery boy wanted to make sure that his grandfather survived and he could continue to exist because "existing is baisicly all I do." So he took his grandfather to a nice secluded cottage in the middle of nowhere so that nothing could happen to him. But it turned out to be a nuclear test site. Fortunatly he was stupid enough to sleep with his grandmother and became his own grandfather.

WOW this forum just sunk to a new low
tht my friend was the most retarded thing i ever read
that is mostly in part due to i didnt even read it lol :)

You could accidentaly hit him with a car or something. Like on Futurama, the delivery boy wanted to make sure that his grandfather survived and he could continue to exist because "existing is baisicly all I do." So he took his grandfather to a nice secluded cottage in the middle of nowhere so that nothing could happen to him. But it turned out to be a nuclear test site. Fortunatly he was stupid enough to sleep with his grandmother and became his own grandfather.
Ass, that's what I wanted to say
:mp5:

The situation itself is impossible, you can't prevent your birth. If you go back in time and kill who you think was your grandfather then it will turn out to have been someone else. If your potential grandfather goes and gets killed before making your father then it won't be you that goes back and kills him.

Think of it like that whole thing with the different possibilities making different dimensions. The "trousers of time." All that happens is that some of the "legs" are removed if your grandfather gets killed, but the only legs that can still remain are those that lead to you being born anyway or someone else killing your grandfather. If you go and kill your actual grandfather then the "legs" that lead to you being born collapse and only those "legs" that are different enough not to be a paradox remain. In essense, while time travel is not logically impossible, traveling to a past in which you can kill your progenitors is logically incoherent. Traveling to that past causes it not to exist so when you get there it turns out that your grandmother got pregnant by someone else or something like that.

Trousers of time?

Pratchett fan, eh? :p

A tangent universe is formed, where in your universe you did not kill your grandfather and hence you were able to be born, and go back in time, kill the grandfather and form the tangent universe in which you were not born.

See, this is why temporal tech sucks ass.

*tells the two doctors to leave*

okay, so heres a brain twister for you.

If you go back in time to kill your own grandfather, what happens? Does nature intervine? Does the gun misfire? Do simply keep slipping in and out of existence due to the fact that, after the bullet exits your grandfather, you cease to exist, thus making the bullet never get fired, thus making your grandfather not die, thus bringing you back into existence, thus restarting the cycle?

hmmmm? :headbang:

you end existance. the universe collapses unto itself. Well done Jackass.
This is why republicans should not be allowed to use time travel.

The answer is rather simple. One of two things would happen.

1) The universe, being driven by fate, will not allow itself and it's own time line to be changed, thus,time would reset to the date you went back in time to, before you went there, and cause existance to go as it intends to.

or

2) You will have created a time\space paradox that, as we all know, would destroy the universe and everything as we know it. :D

Fun isn't it

This is why time travel is impossible. I almost think that the impossibility of time travel is a strong argument for either the existence of God or the existence of a natural order that knows what it's doing.

Hehe. You can't use philosophy to tell a physicist that something is impossible :). Actually Einstein believed time travel was possible (and it works in his equations) assuming certain strange 4-D shapes for the universe. Strangely enough, the most probably 4-D shape for the universe is a hypersphere ... one of the objects that would make time travel possible ;).

With quantum mechanics, there are about a billion and a half things that can work perfectly well as paradoxes. Shroedinger's cat, for instance. Quantum tunnelling. All kinds of stuff. So, with quantum (assuming only a single dimension ... if you assume the kind of exponention dimensions that some people do, this is a moot point), you go back and kill your grandfather. That's fine. It's not actually a paradox because (according to Einstein's equations) you can only travel /back/ in time. You can't go forward. So your quantum wave front still exists (you), but time will now play out differently ... aka, you will not be born this time around (if you live long enough to see your grandfather's grandson/daughter)

Hell, maybe we're all stuck in one big loop right now! We'd never know!

This brings into question what would be involved in going back in time. Firstly, one would have to assume that, whilst in the past, either artificially or naturally you would be protected from the natural effects of the time stream, else as soon as you arrived in the past you would cease to exist, seeing as you hadn't been born yet. With such protection, you would also be protected when you killed your grandfather, so you'd stay alive. However, when you got back into the present, you'd cease to exist as you'd be back into the normal time stream with all of it's effects on you. However, this wouldn't prevent you from having killed your grandfather, because the you who killed your grandfather was protected from the effects of the time stream, meaning he'll keep on existing in the past no matter what.

I hope that makes some vague sense to people, if so please explain it to me!

Mikorlias of Imardeavia

I'd go with Back to the Future logic where Doc Brown says such a situation woud destroy the universe. Simple.

This brings into question what would be involved in going back in time. Firstly, one would have to assume that, whilst in the past, either artificially or naturally you would be protected from the natural effects of the time stream, else as soon as you arrived in the past you would cease to exist, seeing as you hadn't been born yet. With such protection, you would also be protected when you killed your grandfather, so you'd stay alive. However, when you got back into the present, you'd cease to exist as you'd be back into the normal time stream with all of it's effects on you. However, this wouldn't prevent you from having killed your grandfather, because the you who killed your grandfather was protected from the effects of the time stream, meaning he'll keep on existing in the past no matter what.

I hope that makes some vague sense to people, if so please explain it to me!

Mikorlias of Imardeavia

Since when does this force "timestream" get to be an immovable object or unstoppable force? Someone's been reading too much Timeline ;)

*tells the two doctors to leave*

okay, so heres a brain twister for you.

If you go back in time to kill your own grandfather, what happens? Does nature intervine? Does the gun misfire? Do simply keep slipping in and out of existence due to the fact that, after the bullet exits your grandfather, you cease to exist, thus making the bullet never get fired, thus making your grandfather not die, thus bringing you back into existence, thus restarting the cycle?

hmmmm? :headbang:

Since you exist, its proof that somehow everything is turning out how you live it. Lets say you went back in time and killed your grandfather and you dissappeared. Did that happen to the future you? If it happened to the future you, then why do you still exist since he killed your grandfather.

Basically how it works out is that since you exist, something must have happened after the future you killed your grandpa that still caused you to be born.

Oh that's easy .... have sex with your grandmother and become your own grandpa so you'll be immune to the giant floating brains when they attack Earth and you can then, later, save the universe with the help of the Niblonians.

Try a harder question next time.

Some of the interesting theories involved:

I think we all know about the multiverse idea (multiple dimensions that can be altered so if we change the past, we never actually change /our/ past).

We all probably also know about the fixed-time theory that says we /can't/ change the past because it's already happened.

My own interpretation goes along with several other current physicists who say that we could travel /back/ in time and change things, but that doesn't change our known past. The problem then, is we can't travel into the future to see how it worked out ... only further back in time. This is based on quantum physics and wave duality. The real question at that point is: does the future you knew continue to exist or did it never exist?

Another interesting theory is that since time change is constant, you can't move away from a change faster than that change takes place. To rephrase, if you were to change the past, the past would continue to alter as you were there, but if you moved to the future, you would have moved faster than the change could occur, thus everything would still be the same, and now you would be moving (in time) away from the change at the same speed as the change approaching! This borders on the multiverse theory but takes some einstein into account.

Interesting ...

However, if you want just a logical rather than a physics-based time travel paradox, Robert Heinlein came up with one of the best yet devised (in my opinion). I found a link to it:

http://zebu.uoregon.edu/~js/glossary/grandfather_paradox.html

Now /that/ is a paradox.