The Biohybrid–AI Identity Problem: Can the Prodigal Son Return?

As prosthetic humans, embodied AI, biological AI, clones, and personality-reconstruction systems converge across body, substrate, memory, cognition, and relational behaviour, third parties may lose access to facts traditionally used to reidentify persons. This article reframes the resulting problem from a metaphysical dispute over whether A′ is numerically identical to A into an institutional question about how law should act under unresolved identity. Its central case is one in which A disappears, A′ becomes socially embedded as A, and a provenance-superior claimant to A returns. The article proposes a rebuttable presumption of social continuity (RPSC) and claim-level adjudication. Together, these principles preserve established reliance around a non-fraudulent operative identity without treating social recognition as proof of numerical identity. The article argues that return need not entail automatic displacement or complete restoration: institutions should decide only the identity questions necessary for each competing claim while preserving the returning person’s independent legal claims.