Conventional wisdom suggests that people kill people because people once had to kill animals in order to survive. The original sin of carnivorousness explains humans aggressive thirst for blood: War is coded in our genes.
In Blood Rites Barbara Ehrenreich turns that conventional wisdom upside-down. She traces both war itself and the "religion of war" to our archaic experience not as predators but as prey. The fear of becoming cat food taught early humans to band together, to cherish the "sacrifices" of individuals who succumbed, to emulate the hunting skills of predators, and ultimately to associate God with the lions, tigers, bears, and wolves that menaced them. And so people today respond to military threats by staging rituals of solidarity, seeking to make the "supreme sacrifice," and claiming to see Gods steady hand beneath all the gore.
The premise is maddeningly simple, but Ehrenreich skillfully develops it into a comprehensive history of war. In the beginning, she suggests, humans related to large predators in several ways. As prey, we feared the big cats and other natural hunters, while as scavengers we relied on them to share the meat they had killed. And so we developed rituals of sacrifice which re-enacted the trauma of predation and expressed gratitude to the god-like beasts.
Then, sometime in the Paleolithic Age, we rebelled against the beast by sharpening our own predatory talents. The price of this "decisive advance up the food chain" was unshakable guilt and anxiety. Had we betrayed our best selves by becoming predators? Might we become prey once again? Only by building an entire ritual system around sacrifice could we reassure ourselves of our new status.