Biology is commonly divided into domains such as development, physiology, ecology, cognition, and evolution. These distinctions are valuable because they identify different explanatory questions and different aspects of living organisation. Each domain highlights particular patterns of organisation, persistence, and transformation that would be difficult to study simultaneously.
Problems arise when these domains are treated as separate levels of reality. Development is not a developmental level, ecology is not an ecological level, and evolution is not an evolutionary level. Rather, these domains represent different perspectives on the same organised persistence. They reflect differences in explanatory focus rather than divisions within living systems themselves.
The same organism can be investigated developmentally, physiologically, ecologically, cognitively, and evolutionarily without becoming a collection of separate entities. What changes is the perspective through which the organisation is examined, not the organisation being examined. The domains overlap because the living systems they investigate are themselves integrated.
APS therefore treats organisational domains as complementary perspectives on biological organisation rather than as distinct ontological layers. Their explanatory diversity reflects the richness of organised persistence, not the existence of separate levels within nature.
Key Point. Organisational domains are perspectives on organised persistence, not distinct levels of biological reality.