Foundations of Life

This article defines biological agency as the viability-oriented activity through which living systems sustain, regulate, and restore the conditions required for their continued persistence.

Biological organisation is often described in terms of structure, but such descriptions do not explain how living systems sustain themselves over time. This article reconceives biological biological organisation as the pattern of constraint relations through which systems maintain their persistence. It shows how biological organisation depends on constraint closure, gives rise to biological normativity, and enables the emergence of biological agency through the active modulation of biological organisation. Within the APS framework, biological biological organisation is understood as viability-oriented, constraint-closed biological organisation enacted through continuous processes across interacting scales, providing a unified basis for integrating molecular biology, physiology, ecology, and evolution.

Evolution is often defined as change in gene frequencies within populations, but this view does not fully explain what is changing or why such change is biologically meaningful. This article defines evolution in APS as the historical transformation of viability-oriented, constraint-closed biological organisation across generations. It clarifies how evolution presupposes persistence, extends adaptation across generations, and operates on organisational capacities rather than isolated traits. Evolution is thus understood as the long-term transformation of persistence-sustaining biological organisation.

This article explains the research streams of the APS program as organised pathways of inquiry through which the framework is developed, tested, and extended across biological domains.

This article presents a one-page map of the APS framework, showing how its core concepts, explanatory relations, and research pathways fit together in a single orienting structure.

This article identifies the two founding questions of biology as the questions of what life is and how living forms change, and shows how APS integrates them within a unified explanatory framework.

The concept of the organism is central to biology, yet often taken for granted or reduced to structural or genetic descriptions. In APS, an organism is not defined by its components but by its organisation: a dynamically integrated, viability-oriented system that actively sustains the conditions of its own persistence. This article introduces the organism as a processual, agential unity emerging from constraint-closed organisation and maintained through ongoing organism–environment coupling.

This article revisits the question of what life is, arguing within APS that life is best understood as viability-oriented, constraint-closed biological organisation rather than a list of defining properties.

An affordance is a viability-relevant possibility for action.

Biological agency is the activity through which living systems sustain their own viability.

Biological organisation is the constraint-closed organisation of processes through which living systems sustain their own viability.

Cognition is viability-oriented regulation with counterfactual depth.

Constraint closure is the self-sustaining organisation of mutually dependent constraints.

Coupling is the dynamic, processual relation through which organism and environment are co-constituted.

Development is the ongoing reorganisation of constraint-closed processes that sustain and transform viability through time.

The environment is the active field of viability-relevant conditions constituted through coupling.

Evolution is the historical transformation of viability-oriented organisation across generations.

Function is the contribution a structure or process makes to sustaining viability.

Homeorhesis is the maintenance of a viable trajectory through change.

Life is viability-oriented, constraint-closed organisation.

Mattering is viability-relative significance.

An organism is a viability-oriented, constraint-closed biological individual that sustains its own persistence.

Persistence is the ongoing continuity of viability-oriented organisation across time.

Physiology is the coordinated, present-tense activity of processes that sustain viability.

Purpose is the organisation of activity that sustains viability.

Scale is the spatiotemporal organisation through which living processes are coordinated.

Time in APS is organised duration—the medium through which living systems sustain and transform their viability.

Umwelt is the organism-specific domain in which environmental conditions acquire viability-relevant significance.

Viability is the ongoing maintenance of the conditions required for continued biological organisation.