This paper proves that absolute nullity is structurally non-formable within any admissible descriptive framework. The argument proceeds entirely internally, without appeal to ontology, empirical assumptions, or external interpretive standpoints. Definability is shown to require three irreducible capacities: distinction, re-identification, and relational placement. Absolute nullity is characterized as the joint negation of these structural conditions. It is demonstrated that any attempt to define total structural collapse necessarily reinstates the very capacities whose absence it asserts. Introducing purely structural markers ρ and Ξ in a phase-unrestricted setting, the paper proves that minimal structural positivity uniquely determines the boundary between collapse and over-constraint. The main theorem establishes not that absolute nullity fails to exist, but that it cannot be coherently formed as a definable term. Existence, insofar as meaningful, is bounded by structural formability.