Committed Presentism: A Single-History Ontology of Quantum Mechanics

Committed Presentism is a single-history ontology of quantum mechanics in which only the present exists, reality advances through one global now within a causal domain, and one already-decohered branch becomes actual while the others never do. The paper establishes the framework's admissibility: it is coherent, populated by explicit models, and reproduces the confirmed predictions of quantum mechanics on the finite-dimensional algebras in the commit regime and of relativity in the sectors analyzed. Within that scope, the committed present leaves no marginal signature on the pointer algebra or on any unconditioned spacelike-separated marginal; the silence is exact at every record overlap, and optimal discrimination remains at chance. Ensemble-mean energy is preserved in the commit regime. The base structure, eternalism, Committed Presentism, and Stein point-relative becoming are therefore operationally tied within the stated comparison class. Reality is the currently committed configuration and the locus of truthmaking. The future is open because it has not yet committed. The past is a prior configuration, not a stored region; wherever the present-compatible history fiber is non-singleton, the antecedent is not recoverable from the present together with the law. Past-tensed propositions are grounded by the total present, its laws, and its boundary structure, and are gap-bearing exactly when they vary across the histories compatible with that present. If this is how reality works, then the present was never supposed to show up as an extra reading on an instrument. The present is the condition under which any reading is actual at all.