Biology investigates living systems from cells and organisms to populations and ecosystems. Different areas of biology use different concepts and explanations. Understanding how these perspectives fit together, without overlooking their differences, is an important scientific challenge.

The Agency–Process–Scale (APS) framework investigates whether important biological concepts can be made more precise, their relationships more explicit, and their scientific usefulness more readily assessed across different areas of biology.

APS begins with the idea that living systems maintain the conditions necessary for their continued existence through organised biological activity. It examines this activity in terms of agency, process and scale, and investigates relationships among concepts such as viability, function, purpose and cognition. APS is being investigated as a candidate general explanatory framework, not presented as an established replacement for existing biological theories. APS seeks organisational unity without requiring explanatory uniformity: its coordinated perspectives of Agency, Process, and Scale do not replace the independent explanatory contributions of established biological approaches.

For the broader historical and conceptual context, see APS as a Conceptual Framework for Biology.

1. What Is APS Research Trying to Achieve?

The central question is whether APS can help biologists state important concepts more clearly, identify how they are connected, and assess those connections against biological evidence. Its potential contribution may lie in making relationships among existing ideas more systematic and usable, rather than in discovering entirely new biological principles.

The research distinguishes five questions: Are the concepts scientifically precise? Can claims involving them be assessed against evidence? Are their relationships stated consistently? Do those relationships prove useful in scientific work? And, where a comparative advantage is claimed, does APS perform better than the strongest existing alternatives? A positive answer to one question does not settle the others.

2. How Is APS Investigated?

APS claims are compared with established biological explanations and evaluated against relevant evidence. Each comparison identifies the specific question being addressed, what the alternatives already explain, and what result would count against an APS claim. A clearer description is not automatically a better explanation, and an unsuccessful comparison is a legitimate research finding.

Readers interested in the methods can explore Biological Explanation — What Needs to Be Explained, How Should Scientific Explanations Be Compared?, and What Counts as Explanatory Gain?. These explain how comparisons are conducted; they do not themselves establish that a particular APS claim succeeds.

3. What Has the Research Established?

Clearer concepts and relationships

In an initial assessment of six biological concepts, biological agency, function, viability and organised persistence met the specified criteria for conceptual precision. Function also met the criteria for empirical assessability. The other empirical assessments remain unresolved.

A further investigation found qualified support for conceptual integration. APS makes explicit relationships between viability and agency, function and viability, and viability and organised persistence. Relationships involving purpose and cognition still require further investigation. This is a bounded result about conceptual organisation, not proof of improved scientific practice.

For a worked example of how APS definitions can be examined together, see the agency–cognition distinction in the Glossary .

A coherent framework across biological fields

APS research has organised its present substantive work into five areas: Cognition; Development & Regeneration; Evolutionary Dynamics; Ecology; and Social Organisation. These are areas of explanatory work, not five separate levels of biological reality. Foundational ideas and methods can connect them without becoming additional domains.

Subsequent comparisons examined the strongest apparent tensions at the boundaries between these areas. No genuine inconsistency was established in the cases examined, and the assessment did not warrant adding another substantive domain. This supports the coherence of the present organisation of APS research. It does not confirm APS across biology or show that its explanations are superior to existing ones.

Methods that can distinguish different outcomes

Completed methodological investigations have developed ways to compare explanations and examine claims about biological dependencies. One three-case investigation considered planarian regeneration, Pristionchus pacificus mouth-form development and mammalian glucose homeostasis. Its differentiated results included a positive case, a transfer case and a null case, illustrating the importance of recognising when a proposed method does not establish additional explanatory gain.

4. What Remains Uncertain?

APS has not yet demonstrated that its conceptual integration improves scientific practice generally, or that it offers a comparative advantage over the strongest existing approaches. Some controlled comparisons have found equivalent redescription, local dispensability or no established explanatory gain. A study of communication did not demonstrate that APS improved reader understanding compared with an alternative presentation.

These findings help define the limits of present claims. A coherent framework is not the same as an empirically confirmed one; making a relationship explicit is not necessarily an explanatory advance; and results from one biological setting cannot simply be extended to others. Equally, a result described as “not established” is not the same as a result shown to be false.

5. Where Is the Research Going Next?

Current work is examining whether APS's more explicit conceptual relationships can make a demonstrable difference to scientific assessment. This requires moving from clarity and coherence to particular biological questions, evidence and controlled comparisons.

One planned comparison uses experimental research on stomatal regulation in Arabidopsis thaliana, assessed alongside established organisational theory. Independent verification and comparative assessment are not yet complete. The outcome may support, qualify or fail to establish an additional APS contribution.

6. Publications and Research Resources

The resources below distinguish peer-reviewed publication from completed APS research. Completion means that a specified investigation has been brought to a conclusion; it does not imply external peer review, independent confirmation or a positive result.

Agency as the Defining Activity of Life: A Viability-Oriented Framework Integrating Process and Scale

Status: Peer-reviewed publication

The foundational presentation of APS as a viability-oriented account of living organisation, integrating agency, process and scale. Spencer, R. D. (2026). Biological Theory.

DOI · SharedIt full-text access

Domain Consolidation and Cross-Domain Reconciliation

Status: Completed APS Research

Establishes the present five-area organisation of APS research and examines its strongest apparent boundary tensions. Its conclusions concern architectural coherence, not framework-wide validation.

Publications lists formally released scholarly outputs and their publication status. The Articles collection offers broader explanations of APS concepts and applications. APS as an Evolving Intellectual System describes how the framework has been developed, revised and assessed. The Citation Policy explains how to cite APS materials.