You should read The Man Who Folded Himself, by David Gerrold. While it generally sucks as a novel, it does explore this question pretty thoroughly.
Originally posted by: Atomic Playboy
Originally posted by: darkxshade
If we're having a serious discussion and at the same time accept that time travel is possible. Then we should hypothesize based on our history and our present. To date, there is no historical data that shows that a person who had a major impact on the world claim they were able to do what they did because they were from the future. It's hard to accept the fact that ethics and morals alone in the future would prevent someone from attempting to change the past. Then from this I can only conclude that:
A. Time travel is in fact impossible or we as a civilization did not survive long enough to discover it.
B. Any attempt to change the past is doomed to fail or the time traveller has no ability to alter it. Maybe they can travel back in time but become incorporeal and are unable to physically interact in the world, they are only able to observe it. This would explain "ghosts" in a way.
It is also possible that alternate timelines are created where the present is the result of a change to the past but that's all speculative. Additionally, is it just by pure luck or coincidence that our current timeline show no signs of a changed past? Even in infinite alternate realities, it's 50/50.
Don't forget the other obvious theory: time travel exists in the future, but no time travellers want to come back to our time. Let's face it, if you had a choice between going and seeing the dinosaurs or going back and looking at 7th century France, which would you choose?
As for the time travel belief, you can go into the past and change things, but you won't "poof" out of existence simultaneously. The matter that makes up your body is already there, it isn't just going to spontaneously turn into air. You simply divert the timeline into an alternate reality, the likes of which have not yet been explored. In this version of time travel, it is fully reasonable that there could be two (or more) of you in existence simultaneously, which would give you ample opportunity to explore the question "If you have sex with yourself in an alternate timeline, is it masturbation or just gay?"
Originally posted by: Pepsei
3. yes and no, when you go back to the past, it is not your timeline anymore... you can change anything you want and it only affect this new timeline you're in. you may (~1%) or may not (~99%) return to your timeline again, ala sliders.
Originally posted by: RedSquirrel
Originally posted by: Pepsei
3. yes and no, when you go back to the past, it is not your timeline anymore... you can change anything you want and it only affect this new timeline you're in. you may (~1%) or may not (~99%) return to your timeline again, ala sliders.
This is actually my take on it.
Sorta goes like this:
1D is a single line
2D is a flat image
3D is a 3D object
4D is a 3D object transforming or moving over time
5D is a line of 4D "objects" as completely separate entities.
Something like that. Goes up to 10D. Watched a video that explained this concept better then I can. It makes your head want to explode.
Originally posted by: TestedAcorn
Time is something we made up. There is no way to physically reverse the cycle in with the earth has spun, and go back to previous events.
Originally posted by: Beau
neither...
Too lazy to read the thread, but... moving back in time is really just moving to an alternate reality, so any change or impact you have there isn't altering the reality you come from, just the thread that you're currently in and any spawned from it.