The Relatum Problem in Persistence: Diachronic Eligibility and the Limits of Criterion-Based Accounts

Since the revival of the analytic metaphysics of personal identity in the late twentieth century, debates over persistence have remained locked in substantive disputes between rival continuity criteria, such as biological animalism and psychological reductionism. This paper contends that this persistent stalemate arises from an unexamined methodological commitment: the Domain Fixity Assumption (DFA). By excavating this assumption, we uncover the Persistence Relatum Asymmetry Problem. Standard theories require a bearer of persistence relations, yet they insufficiently distinguish the subsequent question of criterion evaluation from the prior structural conditions governing relatum selection. We demonstrate that this internal structural deficit leads directly to Comparative Failure: rival theories evaluate criteria across unacknowledged, non-identical relata without a justified mapping preservation condition. Prior to adjudicating competing criteria, metaphysics must clarify the structural conditions under which a candidate qualifies as a diachronic relatum. We introduce the Diachronic Relatum Eligibility Framework (DREF) not as a relatum selection device, but as a constraint-based framework determining the prior conditions under which competing persistence analyses can be regarded as addressing the same diachronic explanatory relation.