The dual nature of humanity may have emerged much earlier than thought, going by the survival of a person slammed in the jaw in Qafzeh Cave, and some pretty sick children Humankind in deep prehistory is often assumed to have been mild-mannered. Being nomadic, they could just pick up and move on if trouble emerged, such as competition over a resource. They didn't have homesteads to protect, a common hypothesis goes. Bu... [5502 chars]