Why Loss Defines the Boundaries of the Moral Field: A Structural Argument Against Sentience, Rationality, and Autonomy Criteria

Loss is the ontological primitive that defines the boundaries of the moral field: any subject capable of irreversible loss belongs to this field, regardless of whether it is a bearer of obligations or an object of obligations held by others. The paper establishes that loss is the structurally prior grounding — one that does not generate explanatory regress when alternatives are pressed. The central defect of existing criteria — sentience, rationality, autonomy — is a grounding failure: they identify morally relevant properties without accounting for why those properties generate reasons at all. The loss criterion provides this account and is defended through a structural priority argument. Any alternative grounding either denies normativity altogether or reintroduces loss implicitly. Qualifying systems receive default integrity status, placing the burden of justification on the agent who would degrade their enabling conditions. The aggregation algorithm includes an absolute lexical shield: complete destruction of enabling conditions cannot be justified by performance gains. The paper develops a graded theory applied to six system classes and concludes with an explicit five-point research agenda. This paper is Article 1 in the ATTS series. Article 2 (Hlynskyi, 2026): "Why Loss Defines the Boundaries of the Moral Field" is available on PhilArchive.