My world.

[Violet]

Hehe... well, have you ever heard of cause and effect? Cause: I slip on the stairs. Effect: i break my leg and am in general pain. This is causality: that everything has a cause (which is eventually supported by the difference in everything, and change as a result of that difference, because of 1=1). Now, if I went back in time, and stopped myself from breaking my leg: that leg would no longer be broken, because I have changed my past. Simply, if you went back in time, and killed your grandfather: would you still exist?

It is an interesting question, that can be approached in multiple ways... all of which depend on how you define time. Now, under some definitions (single linear path for instance), killing your grandfather would nullify your being born... and therefore you would cease to exist. However, in other versions of time (see quantum theory spiderweb): killing your grandfather would delete all future versions of you that diverge from that thread, although you yourself would probably be fine (you essentially went back into a different time and nullified its causal chain). We call this the grandfather paradox. There are other interesting time paradoxes... but all of them depend upon how time itself is described