Human beings die and kill to establish the truth: prove the reality of the sacred ideal that constitutes the foundation of their society.

The essence of human violence has nothing to do with biology or survival (dead men don't pass their genes along). On the country, human  violence is how we establish our spirituality: devotion to an abstract entity--that "thing" the group worships. The nature of the entity or idea for which human beings die and kill is fungible. Each society has its own "favorite."

The mechanism is the same, regardless of the nature of the idea or entity: death, and memorials erected in the name of those who have died—testify to the reality  of the entity or ideal. Death and memorialization perform a validation function.

The idea of "aggression" (that so many evolutionary psychologists are fond of) is a smokescreen: a form of repression or denial: negation of the truth,

THE BIG LIE THAT MAKES IT POSSIBLE FOR US TO KILL OUR OWN YOUNG MEN.

Pretending that a man is heroic, appealing to his desperate wish to be "masculine," we deny that his role as a soldier is obedience--masochistic submission to the nation-state.