It's all a misunderstanding. If one of us was sent back in time, the first dispute, or, conflict, could've been easily resolved, and us humans never would've learned to fight. If that means that we have to go back to the days when we were fish, we could've easily shown that there is more food in the rest of the sea. We could've shown "Matilda" a beautiful place on the other side of the Mississippi River and her man wouldn't have had to fight, to the death, another man for rights to the shady side of the rock.

We train our animals to be peaceful, why couldn't we train pre-historic humans?