Temporal Buoyancy and the Persistence of Systems: Structural Saturation of Futures as a Necessary Condition for Non-Collapse

Why do certain systems persist over time despite strong irreversible pressures toward collapse? Standard explanations appeal to stability, control, or resilience. This paper proposes a different answer: persistence can arise as a structural consequence of saturated future spaces. We introduce the notion of temporal buoyancy, not as an explanatory mechanism or metaphor, but as a formal impossibility result: in irreversible systems, persistence cannot be coherently described unless certain collapse trajectories are structurally inaccessible. The analysis is purely conceptual and non-empirical. No new forces, laws, or dynamics are introduced. Temporal buoyancy identifies a necessary condition for persistence without stability and clarifies the distinction between persistence as existence and persistence as describability.