The conceptual development of biology has long been shaped by two foundational insights concerning living systems. Aristotle’s biological writings articulated the first systematic account of organisms as intrinsically organised systems whose structures and activities exist for the sake of maintaining the living individual. Darwin’s theory of natural selection provided a second foundational insight by explaining how such organised systems can change historically through evolutionary processes.
These insights address complementary aspects of biological explanation. Aristotle’s biology focused on the biological organisation of living systems and the purposive coordination of their parts and processes. Darwin’s theory explained the historical transformation of such biological organisation through variation, inheritance, and differential persistence across generations.
In compressed form, this relationship can be expressed simply:
Aristotle established the problem of purposive biological organisation in living systems; Darwin explained how such biological organisation evolves; contemporary theoretical biology increasingly seeks to understand how these two dimensions of life are related.
The Darwinian Reinterpretation of Purpose
One of Darwin’s most influential conceptual moves was to reinterpret biological purposiveness. Classical biological thought explained functional biological organisation by appealing to intrinsic purpose: organs and behaviours existed because they served the needs of the organism. Darwin showed that adaptive biological organisation could arise historically through natural selection acting on heritable variation.
As a result, evolutionary theory often adopted the formulation that natural selection explains the appearance of purpose in living systems. Structures appear designed for particular functions not because they were intentionally created for those ends, but because selection has historically preserved variants that enhance survival and reproduction.
This interpretation successfully removed the need for external design in explaining biological adaptation. However, it also encouraged a conceptual tendency to treat purposive language as merely heuristic or metaphorical.
In recent decades, theoretical biology has increasingly recognised that this interpretation leaves an important aspect of living systems unexplained. Evolutionary theory explains how adaptive biological organisation arises historically, but living systems must also continuously maintain and regulate their own biological organisation in the present. Metabolic activity, regulatory networks, developmental processes, and ecological interactions together sustain the organised persistence of living systems despite continual material turnover and environmental perturbation.
From this perspective, natural selection does not simply explain the appearance of purpose. Rather, evolutionary processes historically shape the organisational architectures through which living systems sustain their own persistence.
Why Teleology Disappeared from Biology
The relative disappearance of teleological language from biology during the late nineteenth and early twentieth centuries did not result primarily from Darwin’s theory itself. Rather, it reflected the broader influence of the mechanistic explanatory ideals that dominated the natural sciences following the Scientific Revolution.
During this period, successful physical theories emphasised efficient causes, mathematical laws, and reductionist explanations. Teleological language was therefore often regarded as metaphysical or unscientific. Many biologists consequently adopted strategies for avoiding purposive terminology, replacing it with concepts such as function, adaptation, regulation, or control.
Despite this linguistic shift, the underlying phenomena of organised biological activity never disappeared from biological investigation. Physiological regulation, homeostasis, developmental coordination, and ecological interaction all continued to reveal the distinctive biological organisation of living systems. Contemporary theoretical biology increasingly recognises that explaining these phenomena requires understanding how living systems actively sustain the conditions of their own persistence.
Agency as Persistence-Sustaining Organisation
Within the Agency-Process-Scale (APS) framework, this organisational capacity is described as biological biological agency. Agency refers not to intention or consciousness but to the viability-oriented biological organisation through which living systems sustain, regulate, and recreate the conditions required for their continued existence.
In this sense, purposive biological organisation is not merely an appearance generated by evolutionary history. It is an operational feature of living systems themselves: organisms continually modulate their internal and external conditions in ways that maintain their persistence as organised entities.
Evolutionary processes then act upon these persistence-sustaining systems, gradually transforming the organisational architectures through which biological biological agency is realised.
A Structural Symmetry in the Foundations of Biology
Seen in this light, the historical development of biological theory reveals a striking conceptual symmetry.
Aristotle’s biology investigated how living systems maintain their organised existence in the present. Darwin’s theory explained how such organised systems change historically through evolutionary processes. Contemporary theoretical biology increasingly seeks to integrate these perspectives by clarifying how the persistence-sustaining biological organisation of living systems interacts with evolutionary dynamics across time.
This integration is reflected in the conceptual grammar of the APS framework. The three analytic dimensions of biological explanation correspond closely to the historical concerns of these traditions:
| Historical perspective | APS dimension | Explanatory focus |
|---|---|---|
| Aristotelian biology | Agency | persistence-sustaining biological organisation |
| Darwinian evolution | Process | historical transformation of biological organisation |
| Modern theoretical biology | Scale | coordination of biological processes across time and biological organisation |
In this interpretation, the development of biological theory can be seen as progressively clarifying the relationship between three inseparable aspects of life: the organised activity through which living systems sustain themselves, the processes through which that biological organisation changes historically, and the spatial and temporal scales across which these dynamics unfold.
Reintegrating Organisation and Evolution
From this perspective, biological biological organisation and evolutionary dynamics are not competing explanatory domains but complementary aspects of a unified theoretical architecture. Evolution explains how persistence-sustaining biological biological organisation is historically transformed, while the organised activity of living systems provides the conditions under which evolutionary processes can occur.
The Agency-Process-Scale framework makes this relationship explicit by interpreting biological biological agency as the viability-oriented biological organisation through which living systems sustain their persistence, evolutionary processes as the historical transformation of this biological organisation, and scale as the spatial and temporal domain across which these interactions unfold.
The long historical arc of biological theory can therefore be understood as an effort to integrate two foundational insights: the purposive biological organisation of living systems and the evolutionary processes through which such biological organisation changes across time.
Key Point
Biological theory rests on two complementary foundations: the persistence-sustaining biological organisation of living systems and the evolutionary processes that transform this biological organisation across time.