Quantum Mechanics as the Physics of Observation - version 2

Quantum mechanics has long been taken either to provide an incomplete description of microscopic reality or to require interpretive supplementation to account for its distinctive features. This paper advances a different diagnosis. It argues that quantum theory is best understood as a formal theory of observability, constrained by the physical requirements of irreversible record formation, rather than as a mechanics of observer-independent entities. The central claim is that observation itself is a physical process governed by thermodynamic constraints. Establishing stable, communicable records requires irreversible energy dissipation, and this irreversibility is not a contingent feature of measurement practice but a necessary condition of observational access. Once this constraint is made explicit and treated as explanatorily prior, characteristic structural features of quantum mechanics—contextuality, probabilistic outcomes, non-commutativity, and the asymmetry between unitary evolution and measurement—emerge as consequences of physically admissible distinction-making rather than as indicators of metaphysical indeterminacy or epistemic limitation. On this basis, the Einstein–Podolsky–Rosen incompleteness argument is re-examined and shown to presuppose reversible access to observer-independent properties, an access condition incompatible with the thermodynamics of observation. Hidden-variable programmes and thermodynamic observability are thus revealed to embody fundamentally different commitments about what physical theories can coherently describe: the former posit underlying mechanisms independent of observation, while the latter ground physical description in irreversible observational processes. The paper proposes a reclassification of quantum mechanics as a complete theory of observability under thermodynamic constraint. This is offered as a contribution to conceptual clarification in the foundations of physics, situated at the intersection of quantum theory, thermodynamics, and the historical debate over completeness, without appeal to consciousness-based or speculative ontologies.