David. The time travel paradox comes up in numerous books. General conclusion is that any apparently successful attempt to rewrite just adds another reality to the multiverse without removing the original. Not all in agreement though and P.S. Power looks to be one of them. None the less the paradox ...

If you ended an Earth before human beings arose as a dominant force, then Trillions of possible permutations would be ended suddenly, pruning a large group of worlds with one action. This, in turn, would affect millions (or more) of adjacent realities, which would be subtly shifted around at the ed...

Perhaps the adversaries winning is not as easy as might appear. Think of it as a quantum event. The event being an interaction between realities that don't share accessible dimensions. That means the only way they can interact is as a whole. Each local win for the adversaries acts on the multiverse ...