Fermion Fields Are Not Licensed as Things in Space - A Structural No-Go on Substrate Ontology in Quantum Field Theory

This paper states a narrow matter-side interpretive no-go in quantum field theory. Once fermions are denied the status of tiny hard bits of primitive material stuff, the same ontological instinct is often relocated into the fermion field. The field is then read as a thing in space, with fermions treated as local modes of that thing. The paper denies that automatic inference. A fermion field describes lawful actions: admissible states, transformations, interactions, anticommutation relations, amplitudes, correlations, exclusions, couplings, and observable outcomes. The success of that description, and the occurrence of the actions described, do not by themselves prove that the field materially exists as a thing in space. The argument does not deny quantum fields, quantum field theory, the Standard Model, or fermionic excitations. Nor does it adjudicate against defended field-realist positions on their own grounds. Its target is the unargued default move from successful field use to field-substance. The result is a conservative interpretive restriction: retain the formal inventory and lawful action structure of standard physics while refusing the silent conversion of that structure into material field-stuff. The paper is written as a field-side companion to the author’s photon-side wavefunction no-go and fermion-side corpuscular no-go. Its central mirrored claim is: lawful outcome structure is not path ontology; lawful action structure is not field substance.