Viability and persistence are closely related in APS but distinct. Viability refers to the organisational condition under which a living system can continue to exist—the organisation that distinguishes what supports persistence from what undermines it. It defines what matters to the system.
Persistence is the ongoing achievement of that condition through time. A living system persists only insofar as it actively maintains and modulates the organisation that sustains viability under changing circumstances.
The distinction is therefore not between state and process but between condition and enactment. Viability identifies the organisation that must be sustained; persistence names the activity through which it is sustained.
Key Point. Viability is the condition that makes continued existence possible; persistence is the ongoing activity that realises it.