From Physical Records to Minimal Observers

This paper develops an operational taxonomy of minimal observerhood in physical systems. Its central contribution is definitional rather than cosmological: it separates a transient trace, a persistent record, usable memory, a comparator, and a minimal observer. A bounded system qualifies as a minimal observer only when it retains information about a prior state, combines that retained information with a present signal, uses the comparison to alter later dynamics, and sustains this architecture over a finite persistence window. Thermodynamic embodiment is treated separately. Reliable memory requires metastable state separation or active renewal, while predictive relevance distinguishes useful stored history from thermodynamically costly but future-irrelevant memory. Later finite-regulator tests show that an observer domain can preserve its declared record identity after every original record instance has been replaced, provided renewal, local provenance, comparison, and feedback remain intact. Overlap and redundancy can support fault tolerance, but consensus does not authenticate truth and high record support does not by itself establish observerhood. A downstream companion uses a connected overlap atlas to operationally reconstruct Jacobson’s equilibrium equation of state; that gravitational result requires additional physical assumptions and is not derived here. A standard Markov-chain recurrence result is retained only as a content-blind mathematical coda. It does not prove that observers emerge, only that an already-admitted nonempty observer subset is revisited under irreducible recurrent dynamics. The hard physics remains constructibility, accessibility, provenance, stationary weight, and finite first-passage time.