APS explains living systems as viability-oriented, constraint-closed organisations whose activity contributes to maintaining the conditions of their own persistence across time.
Within this framework, biological phenomena are understood according to the role they play in organised persistence:
- agency concerns the regulation of persistence
- process concerns the organisation of activity
- scale concerns the coordination of organisation across levels and timescales
- cognition concerns viability-oriented evaluation
- semiosis concerns differences that matter for persistence
- function concerns contributions to viability
- evolution concerns the historical transformation of organised persistence
These are not separate explanatory domains. They are interconnected aspects of biological organisation understood through a common explanatory grammar centred on viability-oriented organised persistence.