AbstractCross‐cultural and interdisciplinary agreement as to the universality of aggressive behavior and warfare is compatible with Jung's [(1959): “The Archetypes and the Collective Unconscious. The Collected Works of C. G. Jung, Vol 9, Part I, Para 3.” London: Routledge] theory of archetypes functioning as components of the human collective unconscious. Jungian formulations involve a phylogenetic view of psychic phenomena since archetypes are conceived as neuropsychic entities which evolved through natural selection. It is argued that the banding together of young males for the purpose of aggressive pursuits such as hunting, intergroup conflict, and warfare is a biologically transmitted propensity mediated by archetypal structures in the human brain‐psyche. Universally apparent patterns of affiliative and hostile behaviors are linked to Chance's [(1988): “Social Fabrics of the Mind.” London: Lawrence Erlbaum Associates]hedonic and agonic modes and seen as later ontological expressions of archetypal structures responsible in childhood for formation of bonds of attachment to familiars and avoidance and wariness of strangers. Erikson's [(1984): Yale Review 73(4): 481–486] concept of pseudospeciation is associated with Jung's concept of shadow projection to elucidate the phenomena of patriotism, xenophobia, national paranoia, Lorenz's [(1966): “On Aggression.” London: Methuen&Co.] “militant enthusiasm,” propaganda, and mobilization for war. Finally, it is argued that peace between nations can be promoted through conscious awareness of archetypally determined patterns of intergroup conflict and a collective resolve not to pseudospeciate our neighbors.