Accessibility Propagation and Temporal Direction: A Conditional Structural Analysis

A record tells us what left a trace. When do relations among records also tell us which event came first? Ordinary pointer copying cannot answer: its gates commute, leaving the same complete endpoint state for every visit order. We contrast it with a reversible record-before-exchange protocol. Each station records the carrier's arriving bit, then replaces it by an independent label whose copy is retained. Station-indexed endpoint correlations reveal the predecessor of every station and recover the unknown global permutation. The local gate orientation, one-pass architecture and preparation boundary are supplied; timestamps and chronological station ranks are not. We then follow the resources that make these records available. Joint purity bounds price acquisition, recontact can restore coherence, and renewing a noisy bank removes the entropy of the complete retained state. These are distinct tasks, with distinct physical permissions. The result connects identifiable order to the history and maintenance of records, while leaving the origin of the clock parameter and acquisition boundary as formation questions. Complete proofs, finite-sample constants and renewal protocols are retained in the appendices. Main and Appendices PDFs are supplied separately, with full sources and scientific supplements in the accompanying ZIP.