time travel paradox

"Science tells us..." It's never a good sign. ;o)

The resolution to this paradox is in realising the you wouldn't be going back and 'changing' the past, even if simply by your presence there. If you go back one year in a time machine, you haven't changed your presence/absence one year ago.You haven't altered the past any. Anything you do was already in the past of you going back in time, i.e. your own personal past. The rest comes down to having information others don't but not having information about everything. If you go back to kill your grandfather before you were born, you already know you won't succeed because you attempting to kill your grandfather is already in the past of the world you live in. What you don't know is why.

The mind boggles.Surely if you went back in time,say a year ago and met yourself,you would already know about it.

So is it not possible to kill yourself or travel back in time? You are only exagerating the paradox not solving it.

Not at all. The inability to do something you know you cannot do isn't a paradox. When we make a decision to do something, we have varying levels of degrees of likelihood in attaining the desired outcome. I may plan to post these few words, and the likelihood of doing so is close to certainty,though a power cut may foil this plan. If I plan to publish a novel, there is little to stop me trying, though there are many contingent factors that may stop me, and one fundamental one that almost certainly would (rubbish literary style). If I plan to become Prime Minister of Great Britain, well... it's possible, but incredibly unlikely, but I couldn't tell you exactly which contingent factors would prevent this. If I plan to go back in time and kill myself, I will fail, but I know not why. This isn't a paradox. If I don't know that I will fail and so sincerely plan to carry this out, this is simply a lack of knowledge on my part as much as, say, jumping out of a window to take flight by flapping my arms. And if I do know I will fail, then in truth I'm not really going to try and am only going to learn why I couldn't.

If you knew about it you would have no free will not to go back..it would be written..

A thousand suicidal maniacs get in a time machine and go back and attempt to kill themselves..they all fail..They obtain ten thousand time machines and get twenty thousand volunteers to go back and kill themselves..they all fail???:perplexed: This is not mission impossible its a proposed reality experiment..you cant say its not a paradox just because you dont know..

Not at all. The inability to do something you know you cannot do isn't a paradox. When we make a decision to do something, we have varying levels of degrees of likelihood in attaining the desired outcome. I may plan to post these few words, and the likelihood of doing so is close to certainty,though a power cut may foil this plan. If I plan to publish a novel, there is little to stop me trying, though there are many contingent factors that may stop me, and one fundamental one that almost certainly would (rubbish literary style). If I plan to become Prime Minister of Great Britain, well... it's possible, but incredibly unlikely, but I couldn't tell you exactly which contingent factors would prevent this. If I plan to go back in time and kill myself, I will fail, but I know not why. This isn't a paradox. If I don't know that I will fail and so sincerely plan to carry this out, this is simply a lack of knowledge on my part as much as, say, jumping out of a window to take flight by flapping my arms. And if I do know I will fail, then in truth I'm not really going to try and am only going to learn why I couldn't.

Hey, time travel machines are an incredibly unlikely thing. Given that, 1000 suicidal time travellers is incredibly unlikely. Given that, that they all fail is, yes, incredibly unlikely. It seems to me the odds are converging to zero somewhere along the line, and I just don't think it's at the assassination attempt stage. It is impossible that I exist when in the past my future self tried to kill my grandfather... and succeeded. i.e. statistical likelihood = zero. Thus repeating the experiment 100, 1000, 1000000000000000 times makes no difference. Again, not a paradox. A thousand maniacs jumping out of windows and not one of them manages to levitate? Not really a problem.

I agree,I think that there would be restrictrictions but what those are we dont know.

Thats not acceptable to say we dont know..This aint science this a philosophical debate asking what is possible and what is not..

I think you have your probabilities upside down..A million nutters jump out the window, they will all die..Tell me when it becomes impossible...I go back in time... i have a gun ..i shoot myself..You choose which is the impossible and why..No hidden i dont knows..

What do you is think is possible in time travel,you say it is not possble to go back and kill your grandfather,what I meant is we do not know why it is not possible to go back in time and not be able to kill your grandfather,we dont why there are constrictions?

Yes, and a million nutters go back in time to kill themselves and they all fail, since it is not possible. And the reason it is not possible is that the million nutters back in time is already in the past of those million nutters deciding to go back in time, thus nothing has changed.

Im not saying what is possible but i am saying you cant say there are unknown restrictions to killing yourself.I dont think its possible to go back in time because of this paradox, but thats just my logic.If i give you gun and say go back in time and kill hitler, if you succeed history changes beyond recognition and the world is completely different.I cant resolve the paradox whatever way i make events change..Time is a linear event and it goes one way and science is wrong when it claims the possibility of time travel ,,your wrong Einstein wrong..

Why are you avoiding the question..they have arrived at the point of killing themselves in the past... they kill themselves.. now what??? Remember they are now dead they cant go forward to now to go back to kill themselves..

Im not saying what is possible but i am saying you cant say there are unknown restrictions to killing yourself.I dont think its possible to go back in time because of this paradox, but thats just my logic.If i give you gun and say go back in time and kill hitler, if you succeed history changes beyond recognition and the world is completely different.I cant resolve the paradox whatever way i make events change..Time is a linear event and it goes one way and science is wrong when it claims the possibility of time travel ,,your wrong Einstein wrong..

Did Einstein claim time travel was possible? I know Hawking has said it might be, but not in a way that would effect local history (it involves wormholes and there aren't any near where my grandad or Hitler used to live).

Paradoxes don't stop engineers from building things. You can't say 'Time travel is impossible because of this paradox'. Time travel is impossible, sure. If it weren't, would you have a paradox? No. Because the past is the past, even if there are time travellers in it. Whatever said time travellers did in the past, it has happened, even if those travellers are our future selves. But the most likely reason why no-one can try and cause a paradox anyway is that time travel is impossible, not the other way round. And the reasons time travel is impossible come down to more fundamental physical laws, not paradices. (is that a word?)