This article presents a minimal framework of Defensive Ethics grounded in the natural architecture of agency and the dynamics of interpersonal violence. It introduces five principles—Self-Preservation, Equality, Reciprocity, Coherence, and Congruence—as orientations that sustain safety and moral integrity when threat compresses deliberation and destabilizes the Self–Other field. Drawing on biology, relational structure, and reflective judgment, it clarifies when defensive action is justified, how it must be calibrated, and what conditions preserve ethical legitimacy, forming a unified, naturalized foundation for self-defence.

This article traces how moral value emerges from the basic conditions that sustain life. Beginning with viability—the capacity of living systems to remain intact—it shows how evaluative sensitivity develops into meaning, moral discernment, and ultimately the worth of agency. As this worth becomes explicit, the principles of Self-Preservation, Equality, Reciprocity, Coherence, and Congruence acquire prescriptive force. Value arises from life’s own organizing intelligence, revealing why defensive action carries ethical weight and how moral responsibility grows from the conditions that make agency possible.

Defensive Ethics reaches its fullest clarity when its five principles are understood as a single, integrated system. Together, they form a living moral ecology that stabilizes the Self–Other field under threat. Self-Preservation identifies what must be protected; Equality anchors shared standing; Reciprocity guides calibrated response; Coherence steadies judgment; and Congruence aligns action with purpose. Their coordinated expression enables agents to navigate volatility without abandoning moral structure, preserving both viable agency and the relational conditions that give defensive force its ethical meaning.

Congruence is the principle that preserves correspondence between moral intention and the lived shape of defensive action. It ensures that protective force remains aligned with the conditions that justified its initiation and adjusts as those conditions evolve. By linking judgment to execution across the arc of an encounter, Congruence guards against drift into dominance, retaliation, or excess. It expresses the defender’s commitment to preserve agency, relational stability, and moral integrity even under threat.

Coherence is the principle that keeps perception, evaluation, and action integrated when threat compresses time and emotion rises. It preserves the defender’s moral orientation by ensuring that defensive behaviour reflects the structural conditions that make agency possible. Through case studies, the article shows how Coherence stabilizes the relational field, prevents defensive action from drifting into excess or distortion, and maintains continuity between moral purpose and the form that protective movement takes as an encounter unfolds.

This article develops the Principle of Reciprocity, the third pillar of Defensive Ethics. Reciprocity shows how shared moral standing becomes action-guiding: it requires agents to adjust their conduct in response to the shifting realities of others whose agency is equal in worth and vulnerability. Through two case studies, the article demonstrates how reciprocity legitimizes defensive intervention when properly calibrated—and how defensive legitimacy collapses when force exceeds what changing conditions can justify.

This article develops Equality as the second principle of Defensive Ethics, showing how the shared conditions of agency—bodily integrity, recognition, and freedom from coercion—form the moral foundation for legitimate defense. It explains how interpersonal violence collapses this symmetry and why defensive action is justified only when it restores the standing an aggressor has suspended. Through case studies, the article illustrates Equality as a structural discipline that binds protection to mutual regard and prevents defense from devolving into domination.

Self-Preservation is the foundational principle of Defensive Ethics. It identifies what is morally at stake in violence—the protection of the conditions that sustain agency, autonomy, and dignity. Rooted in biology and developed through reflection, it transforms survival into moral responsibility. To defend oneself is to safeguard the structural integrity that supports moral life while recognizing the equal standing of others. From this foundation arise the further principles that guide ethical restraint and proportion in self-defense.