This paper examines whether terminal plurality—the existence of multiple distinct invariant endpoints—can be structurally sustained within the Modal–Dependence Calculus (MDC). Building on the axioms and topology established in earlier work, it demonstrates that plurality is not incoherent but structurally unsustainable under the MDC constraint set. The argument proceeds by showing that, at the terminal layer, all structural resources capable of grounding a difference between candidate endpoints—modal profile, upstream dependence, and downstream relational structure—are exhausted. In the absence of any symmetry-breaking resource, terminal candidates are structurally indiscernible, and A8 formalizes their collapse into identity. The result is a conditional derivation: within systems satisfying A0–A8, structural monism emerges not as a metaphysical posit but as the consequence of structural exhaustion.
Austin Jacobs (Fri,) studied this question.