Harris opens the chapter with stories of ancient and modern ‘primitive,’ as he calls it, people engaging in warfare. He then explains that warfare came from the need to control population growth rather than other reasons past anthropologists have listed. ‘War as solidarity’ is not accurate because there are other ways groups bonded. ‘War as play’ is not valid because individuals can be taught to hate war as easily as they can be taught to love it, and groups did not punish intragroup pacifists. Harris argues that ‘war as human nature’ is untrue because how we control our aggression, like starting a war versus letting it out in a different way, is entirely based on culture. Finally, ‘war as politics’ is not a strong theory because not all villages try to conquer territory and other groups.