that means you wouldnt exist the moment you thought of doing that. But if somehow you did kill your grand pa, then maybe he wasnt your grand pa. Like in futurama, the dude goes back and gets his grand pa killed, but he still exists, why? Because he banged his grand ma in the past thus creating him in the future. Weird? Yes.
Going back in time means that time doesn't pass but exists as a parallel. If you can move along the parallel, both forward and backwards it means that time is not a parallel line but a plane. On that plane your grandfather exists in a set of parallels. You exist in a set of parallels. If you kill your grandfather before the child of that grandfather was conceived you change the plane of existence that is no longer a single plane but a pair of co-related planes or a series of planes stacked on top of each other up to skyscraper heights. On some of those planes you exist. On some you don't. My personal theory on deja-vu is that we are already several planes high and deja-vu is nothing more than reliving another plane's past and remembering a hint of what we already lived in one of our parallel/plane/cube existences.oz
"Popular dissidents are merely pacifiers given to us by the Government to keep us in line and thinking someone is making a ruckuss."
alternate universes...okay but if you stick to the same universe and just go back in time and kill ur grandfather/ur past self then what or kill them all highly improbable but anyway
It would seem to me, that if you existed in the first place, to go back and murder your grandfather that you yourself already existed in a parallel universe, yes? Because you existed, you could not stay in the same timeline.
"Oops, it appears I have run over your dogma with my karma."
what happens.... 
