Coherence as an Operational Observable

This work proposes coherence as an operational observable defined through procedural exclusion rather than direct measurement. Instead of assigning values to physical quantities, the framework detects deviations from internally maintained coherence under isolation. The method does not confirm states or events but excludes incompatibilities, functioning as a null-type experiment. The approach introduces the concept of procedural truth, where objectivity emerges from agreement between independent coherent systems rather than reference to external standards. This enables validation of phenomena beyond existing measurement paradigms and supports detection of events not yet associated with defined observables. The framework is intended as a conceptual and methodological contribution at the intersection of physics, metrology, and philosophy of science, and is presented as a preprint for open scientific discussion.