The Ontology of Vacuum - From Empty Space to Coherence Vacuum

The concept of vacuum occupies a central yet unstable place in the history of physics. Acrossclassical mechanics, relativity, quantum theory, quantum field theory, cosmology, and particlephysics, the word vacuum has named radically different conditions: empty space, absence ofmatter, lowest-energy field state, symmetry-bearing ground state, metastable energetic regime,and cosmological background. This paper argues that these are not merely technical variations of one idea, but distinct vacuum concepts belonging to different levels of ontological depth. Most existing vacuum models, however sophisticated, remain defined within alreadyconstituted structures such as spacetime, field ontology, energetic ordering, or symmetryframeworks. They therefore do not reach the deepest generative condition from which suchstructures emerge. In response, this paper develops a comparative ontology of vacuum and introduces the conceptof the coherence vacuum: the pre-relational, pre-dimensional, fully coherent generativesubstrate from which dimensionality, curvature, fields, mass, force, and derived vacuum statesemerge through structured reduction. Within this framework, the quantum vacuum isreinterpreted not as ultimate foundation, but as a reduced or exhausted-potential vacuuminternal to an already structured regime. The paper presents a hierarchy of vacuum concepts,distinguishes absence-based, geometric, energetic, differentiating, and generative vacua, andargues that the coherence vacuum provides the deepest category in this hierarchy. Vacuum isthereby redefined from emptiness or baseline energy into ontological source condition. Keywords Vacuum ontology; coherence vacuum; quantum vacuum; field vacuum; Higgs vacuum; falsevacuum; cosmological vacuum; emergence; ontology of physics; generative substrate