In "The Castle in the Forest," Norman Mailer examines the complex nature of pacifism and the inherent conflict within individuals who adopt this stance. He suggests that deep within the psyche of a pacifist lies the potential for violence, which might be a motivation behind their commitment to peace. This internal struggle highlights the duality of human nature, where a desire for harmony is intertwined with the instinct for aggression.

Mailer implies that the journey towards becoming a pacifist is often shaped by personal experiences with violence and conflict. This background contributes to their strong aversion to harm and desire for a peaceful existence. By acknowledging the existence of this "killer" within, the narrative delves into the reasons a person may actively choose the path of peace while grappling with their darker impulses.