Biological Explanation is the scientific practice of making biological phenomena intelligible by identifying and supporting the relations, processes, structures, histories, organisations, and other dependencies relevant to the explanatory question being asked.
Biology employs multiple legitimate explanatory approaches. Depending upon the explanandum, explanation may be mechanistic, causal, constitutive, developmental, evolutionary, ecological, functional, organisational, historical, informational, mathematical, or involve combinations of these. Their adequacy depends upon the explanatory question, the evidence available, the relations claimed, and the inferential responsibilities of the particular account.
APS does not treat this explanatory plurality as requiring all biological explanations to be absorbed into one framework. Nor does it claim that viability-oriented organisation, organised persistence, or Agency, Process, and Scale must appear explicitly in every adequate biological explanation.
Within APS, however, biological explanation is given a distinctive organisational emphasis. APS investigates living systems as viability-oriented, constraint-closed organisations and gives explanatory priority to how such organisation is maintained, re-established, and transformed through change. Organised persistence is therefore a principal explanatory target within APS, not a stipulated universal explanandum for biology as a whole.
Agency, Process, and Scale articulate this APS perspective. They are analytic projections of one viability-oriented organisation: Agency concerns what living systems do; Process concerns how continuity is maintained despite change; and Scale concerns where persistence is organised across spatial and temporal extents. They provide APS with a coherent explanatory architecture without functioning as obligatory categories for other biological explanations.
Explanatory integration within APS is likewise methodological rather than compulsory. Mechanistic, evolutionary, developmental, ecological, functional, organisational, and other explanations may address different questions and make different epistemic contributions. APS may compare or relate them where doing so clarifies biological organisation, but explanatory plurality does not by itself require synthesis.
Where APS represents relationships through explanatory pathways, those connections are dependency hypotheses rather than established results. Architectural Dependency identifies the commitments represented by APS pathway architecture, while the framework-neutral Dependency-Hypothesis Audit provides a procedure for specifying and assessing individual dependency claims against appropriate evidence, alternatives, scope, failure conditions, and the strongest relevant established explanation.
Biological explanation in APS is therefore neither a replacement for existing explanatory practices nor a claim that all biological understanding must converge upon APS. It is a comparative and integrative explanatory methodology organised around a substantive APS interest in viability-oriented organisation and organised persistence.