Temporal paradox

A temporal paradox is when something happens in the past that affects the future, but that same event couldn't have happened in the future because it only happened in the past. It's like a puzzle - something that makes you scratch your head and think! Think of it this way: if something happened in the past that changed the future, that means that it had to have happened in the future first in order for it to happen in the past. But that makes no sense! That's what a temporal paradox is.