Grandfather Time Paradox

[Reality_is_a_Dream]

Here is the thing. I go back in time to kill my granpy. Sounds violent, but bear with me. Since he's is dead, he never concieved my dad, and him not me. So I never existed. But since I never existed, Grampy was never killed, and is thus alive. So my dad is too. And so am I. So time, and there for reality, ceases to exist. Poof. An ideas?

[ClouD]

You still exist. You are the constant between time, even if he is not. After killing your grandfather, you could remain in the same time, and he would still be dead. If after you killed him, you went to future, he would remain dead, and you would be alive since you existed in the past (when you killed him).

[Reality_is_a_Dream]

You still exist. You are the constant between time, even if he is not. After killing your grandfather, you could remain in the same time, and he would still be dead. If after you killed him, you went to future, he would remain dead, and you would be alive since you existed in the past (when you killed him). I see a flaw. Lets say I go back in time and killed someone of great importance. All of his or her "acoplishments", or everything that he or she made would cease to exist. When I killed my grandfather, I ceased to exist, which means all of my acomplishments and the results of my existince also cease to exist. So since I never was born, my grandfather is alive. Do he gave birth to my dad, who gave birth to me, who killed my grandfather. So I wouldn't still exist in the past, and I couldn't go into the future.

[ClouD]

If your grandfather made a clock in current time, and you went back and killed him, the clock would not be made/assembled. Unless you brought the clock back when you killed him. _____ You would exist if you went to the future from there. You would exist, because you existed in the time you killed your grandfather.

[Reality_is_a_Dream]

Naa, man, I'm going by Terminator physics. You can't bring anything back except the skin on your back.

[bcomp]

Oh time travel! I love time travel! Well, since you can't kill your grandpa, without effectively killing yourself, you'd probably not be able to kill him. Like... if you tried to shoot him, the gun would fall apart or the bullet would bounce off his chest or something. Either that or you would kill him and then at that exact moment, time would just freeze up and restart. Ha. I think if you could kill him though... you'd probably remain in that timezone and find out that your grandma actually was impregnated by... *GASP* another man! And, to ensure your own existence... you'd have to be that man. dun Dun DUN!

[Reality_is_a_Dream]

lol, that is like South Park style time travel.

[Carôusoul]

I understand ClouD's point, but it is immensely difficult to put into words.. Constant, is the key word. You are constant.. ahk. I'll be back when I've figured out quite how to say this easily.

[Reality_is_a_Dream]

lol. Go for it, man.

[ChaybaChayba]

Here is the thing. I go back in time to kill my granpy. Sounds violent, but bear with me. Since he's is dead, he never concieved my dad, and him not me. So I never existed. But since I never existed, Grampy was never killed, and is thus alive. So my dad is too. And so am I. So time, and there for reality, ceases to exist. Poof. An ideas? When you go back in time, since in reality, there is no time, you will have to reconfigure the whole universe and change it so it would match the time you want to go back to. So when you kill your grandfather, you won't die, because you already exist. Time never existed! It's only a concept of the humand mind to better understand reality.. in your head you see a timeline on which you can go back and forth in order to 'travel in time'. But in reality, theres no such thing as a timeline, theres only right now.

[Xei]

Two different answers: 1. When you go back in time and change something you create an alternate universe/timeline. 2. Travelling backwards in time is impossible.

[bcomp]

lol, that is like South Park style time travel. Lol yeah. They do it in futurama too. Both great shows ha. But in reality, theres no such thing as a timeline, theres only right now. Waidaminute... isn't "right now" a time?

[The Cusp]

The John Titor model of time travel covers that. You don't really travel back in time, but just visit a parallel universe that is farther back in time. So if you kill your grandfather, it's just that universe's version of him. Your real grandfather in your universe is unaffected.

[Taosaur]

You still exist. You are the constant between time, even if he is not. After killing your grandfather, you could remain in the same time, and he would still be dead. If after you killed him, you went to future, he would remain dead, and you would be alive since you existed in the past (when you killed him). When you go back in time, since in reality, there is no time, you will have to reconfigure the whole universe and change it so it would match the time you want to go back to. So when you kill your grandfather, you won't die, because you already exist. I'm with these guys (and Omicron, if I understand what he's not saying correctly ). If you go back in time and kill your grandfather, you will be in a here-and-now where you exist and your father does not. Your past won't repeat, but you will still exist. Assuming you have this power to translate your present view into a causally distant world-state, perhaps it would be harder, after you kill grandpa, to translate back to a state matching the continuity you left behind, but you wouldn't ultimately be changing anything about the universe--just the way you're looking at it.

[Replicon]

The assumption that you can't exist if grampy never had your dad is based on causality. Time travel requires a breach of causality. So, I figure, as long as you're breaking the rule of causality, there's no reason why you should cease to exist like in Back to the Future.

[JET73L]

How it can work: Timelines-You go back to, say, 50 years ago on your current timeline, and kill your grandfather. You then proceed along a timeline where he died earlier tthan in your original timeline, and your parent was not born (see DragonBall Z, androids-post cell games) Cheating grandma-you go back in time, again 50 years, kill your grandfather. Your parent is born anyway, and then eventually you, but only because your grandfather wasn;t your biological grandfather in the first place. Anti-paradox system built into universe- You go back in time. Again 50 years. You aim a handgun from the present time at your grandfather, pull the trigger, and it jams. You try to knife him, but get hit by a bus. You may even suicceed in knifing him, but he survives, and your parent is born anyway whike you are sitting in a jail cell in the 1960s on a charge of convicted murder. You then remember having been told the story of when you grandfather fought of a murderer, either as history changes or as your past self is told the story in the '80s or '90s. Known history is concrete- same as anti-paradox method, but you never even found your grandfather, and were never arrested, and eventually gave up and went back to the present. You were in the past, and may have altered it, but not in any way tht it changed how you or anyone in the present remembers that period of time. Messing with unclear explanations- Your dad is forty. you go back in time 20 years and kill your grandfather. Your dad was already born, and you succeeded in doing something that was only impossible if you assumed certain unspoken factors were true. You are born anyway. Lots of ways this could work. Edit: PS: that wqas one of the things that annoyed me about back to the future. If you disapoear because you change your past, you probabily ouldn;t fade depending on the statistical probability that you, personally, would be born. You would likely either disappear right after the change occured, or not disappear at all. As for the photographs, that would be even more so. The only one that even remotely made sense was the one in the 3rd movie, which was taken spcifically because of the time travel, all other pictures would have either been taken or not, or of someone else. It would make no sense for Marty's parents to take a pictgure of a tree in front of which their nonexistent children weren;t standing.

[Taosaur]

Edit: PS: that wqas one of the things that annoyed me about back to the future. If you disapoear because you change your past, you probabily ouldn;t fade depending on the statistical probability that you, personally, would be born. You would likely either disappear right after the change occured, or not disappear at all. As for the photographs, that would be even more so. The only one that even remotely made sense was the one in the 3rd movie, which was taken spcifically because of the time travel, all other pictures would have either been taken or not, or of someone else. It would make no sense for Marty's parents to take a pictgure of a tree in front of which their nonexistent children weren;t standing. Plus everyone knows you can travel back in time at 72mph if you adjust your flux capacitor and use the proper weight of engine oil.

[Xei]

lolumz. Yeah seriously, it was just an artistic/tension thing. Never considered how the movie would've sucked if Marty suddenly disappeared and the credits rolled? :\ Hate to break it to ya, but it wasn't a documentary.

[JET73L]

^^61mph if you use NOx. Yeah, it was just something that ticked me off, how it faded with the siblings disappearing, and even with the sweatshirt vanishing after the person wearing it. I just figuredit would have worked better if the picture had changed completely to reflecty the entire change in timelines each time the past was affected to stop Marty existing. Also, thought of another possibility: A time machine could merely recreate the universe as it was on the date to which you travelled, then project it into a pocket universe that was neither in the past nor another timeline, but a pocket universe based on the present being 50 yuears porevious. SO the man you killed would not have beemn your grandfather, but rather a construct that used your grandfather as a template.

[juroara]

*shrugs* I really am not convinced going back in time is even possible. as far as I am concerned the only time that exists is right now. going back in time is nothing more be reliving a memory as clear as day. but you can not interact or change anything this question then, becomes moot but I guess only time will tell!!

[Xei]

In fact time has already told. There's nobody here from the future.

[ClouD]

In fact time has already told. There's nobody here from the future. once upon a time in now, there sat a boy now ebbed away and he stay in time a fly landed upon this screen and laughed, speaking words truer and more accurate than typing itself the boy dismissed the fly, swatting as it flew to the gnats later upon now, he saw the birds, the gnats, the trees he heard their laughter, and saw the fly in each of them laughing alongside, each he became without form, but laughter

[JET73L]

An even more interesting paradox is the Crucifixion Audience paradox. Unless laws are made spedcifically to forbid going to recorded occurences in history, then any popular even in the past is going to have thousands, or even more, spectators.

[Xei]

once upon a time in now, there sat a boy now ebbed away and he stay in time a fly landed upon this screen and laughed, speaking words truer and more accurate than typing itself the boy dismissed the fly, swatting as it flew to the gnats later upon now, he saw the birds, the gnats, the trees he heard their laughter, and saw the fly in each of them laughing alongside, each he became without form, but laughter lawl

[SuperSmashcz]

lol if it were possible to go back in time and kill your grandfather the vastness of space would kill you first The earth moves at 67,062 miles per hour in total (around sun, around galazy, then galazy moving through space) if you were to time travel u would end up in space because the earth would not have been in the spot that u left it at. But, it u were able to sucessfully time travel and live you are moving through parrell dimensions. There are a infinite number of them and there is one where you pop out of nowhere and kill ur grandfather. Its a really fascinating subject. Use google to get more info on it.