Conventional framing
A constraint is typically treated as a passive boundary condition that limits or channels physical processes, often understood as an externally imposed restriction.
APS reframing
In APS, a constraint is an active boundary condition and organisational relation that shapes viability-oriented activity without predetermining outcomes. Constraints channel flows of energy, matter, and information in ways that stabilise and coordinate living processes, enabling coherence while preserving adaptive flexibility.
By guiding transformation rather than fixing outcomes, constraints define the causal architecture of living systems: they make order possible through limitation. When constraints form a self-sustaining network, constraint closure arises, grounding organised persistence and enabling biological agency.
Constraints therefore provide both the structure that supports persistence and the flexibility that enables adaptive change.
Key Point
Constraints are the organisational relations that channel activity without fixing outcomes, enabling both the persistence and adaptive flexibility of living systems.