Introduction

Scientific theories do not simply accumulate observations; they organise them through conceptual frameworks that determine what counts as an entity, what counts as a cause, what is taken to have explanatory priority, and how phenomena become intelligible within a domain. These frameworks function as explanatory grammars: structured sets of conditions that define how phenomena become intelligible within a domain.

Taken together, explanatory grammars integrate four dimensions of scientific understanding: ontology (what exists), causation (what counts as a cause), explanatory structure (how phenomena are made intelligible), and explanatory direction (how explanation is oriented between components and organised systems).

Just as linguistic grammar structures meaningful sentences, explanatory grammar structures meaningful scientific accounts. It determines which entities appear in explanation, which relations count as causal, and what constitutes an adequate explanation.

Scientific progress often involves changes in explanatory grammar: new ways of organising phenomena that render previously obscured patterns intelligible. Biology provides a particularly demanding case, because living systems are dynamically organised, historically evolving, and coordinated across interacting spatial and temporal domains.

Explanatory Grammars in Science

Across the sciences, explanatory frameworks organise phenomena through characteristic sets of categories. These are not arbitrary descriptors but determine what is treated as causally relevant.

Newtonian physics: mass – force – motion → mechanical causation

Thermodynamics: energy – entropy – state → transformations of energy

Electromagnetism: field – charge – interaction → distributed physical influence

Darwinian evolution: variation – inheritance – selection → adaptive change

Information theory: signal – code – transmission → informational organisation

Such grammars shape what is measured, what is treated as causal, and what counts as explanation. When explanatory grammars change, scientific understanding changes with them.

Why Biology Is Especially Sensitive to Grammar

Living systems are organisationally complex, self-maintaining, historically evolving, and coordinated across multiple interacting scales. Because of this, biological explanation has developed through multiple partially overlapping grammars, each emphasising different aspects of life.

These grammars capture genuine features of living systems. However, they also tend to privilege particular components or processes as explanatorily primary, generating recurring debates about the “fundamental unit” of biology.

Major Explanatory Grammars in Biology

Gene-centric grammar explains biological change in terms of gene frequencies across generations, enabling precise modelling of evolutionary dynamics while offering a limited account of organismal organisation.

Cell-centric grammar establishes the cell as the fundamental unit of life, grounding development and physiology while remaining less explanatory for evolutionary dynamics.

Organism-centric grammar emphasises integrated regulation and environmental interaction, providing a strong account of functional organisation but weaker formal modelling of evolutionary change.

Systems biology grammar focuses on networks, interactions, and distributed dynamics, enabling multiscale modelling while often under-specifying biological normativity.

Each grammar captures a real aspect of biological organisation. Each also risks treating a particular component or scale as explanatorily primary.

The Problem of Privileged Scale

Despite their differences, these approaches share a common assumption: that biological explanation must identify a privileged scale of causation. At different times, genes, cells, or organisms have been treated as foundational explanatory units.

This assumption reflects patterns familiar from engineered systems, where causal control is hierarchically organised. Living systems, however, do not conform to such structures. Their organisation is distributed, reciprocal, and dynamically maintained.

This tendency reflects not only a focus on scale but a deeper orientation in explanatory practice. Many biological explanations are implicitly analytic, privileging explanation in terms of components over explanation in terms of organised systems. What appears as a problem of identifying the correct level of causation is therefore more precisely understood as a bias in explanatory direction (see Analysis, Synthesis, and the Direction of Explanation).

A related tendency appears in theories of cognition and behaviour. Biological organisation is often interpreted through concepts derived from human cognition — such as representation, computation, inference, or decision-making — rather than understanding human cognition itself as a specialised form of biological organisation. This reflects a common explanatory inversion in which concepts abstracted from highly derived forms of biological organisation are projected back onto life in general.

APS reverses this explanatory orientation. Rather than beginning with human cognition as the explanatory model, it understands cognition as emerging from viability-oriented, constraint-closed organisation. Human cognition is therefore treated not as explanatorily primary, but as a specialised expression of more fundamental biological organisation.

Reductionism can therefore be understood not simply as a commitment to smaller scales of explanation, but as a partial explanatory grammar that privileges analytic direction and component-based explanatory priority.

Distributed and Reciprocal Causation

In living systems, causation is not confined to a single scale but propagates across interacting processes. Molecular dynamics influence cellular organisation; cellular activity reshapes molecular processes; physiological regulation modifies gene expression; organismal activity alters environmental conditions.

Causation is therefore distributed and reciprocal rather than hierarchical. Biological explanation must account for this organisation without reducing it to a single privileged domain.

From Explanatory Grammar to Continuity Architecture

Explanatory grammars identify the categories through which phenomena become intelligible. APS extends this insight by asking what kind of organisation biological explanation must ultimately explain.

Living systems do not merely exhibit activity, process, or multiscale coordination. They persist. Organisms continually replace components, reorganise internal processes, respond to perturbations, and adapt to changing conditions while maintaining their identity as living systems. Biological explanation must therefore account not only for what organisms do but also for how organised persistence is maintained through change.

APS describes this persistence as a continuity architecture: a viability-oriented organisation that continually regenerates the conditions required for its own continuation. Agency, process, and scale are not independent explanatory domains but mutually dependent dimensions through which organised persistence is realised.

The APS explanatory grammar therefore differs from many traditional biological grammars. Rather than treating genes, cells, organisms, or networks as explanatorily fundamental, it treats organised persistence as the central phenomenon requiring explanation. Biological entities, mechanisms, developmental processes, ecological relations, and evolutionary transformations become intelligible insofar as they contribute to the maintenance, modification, or failure of this continuity architecture.

The APS Explanatory Grammar

The Agency–Process–Scale (APS) framework makes explanatory grammar explicit and grounds it in viability-oriented, constraint-closed organisation. Within this grammar, living systems are understood as actively sustaining the conditions of their own persistence through ongoing processes coordinated across interacting scales.

Biological explanation therefore resolves into four inseparable dimensions:

Agency — viability-oriented regulation.

Process — the dynamic organisation of activity through time.

Scale — the coordination of activity across spatial and temporal domains.

Organised Persistence — the continuity-preserving organisation that integrates agency, process, and scale into a viable living system.

Agency, process, and scale are not independent categories but analytically distinct aspects of a single organisational reality. Organised persistence functions as their integrative centre.

Living systems regulate because persistence requires regulation. They undergo continual transformation because persistence requires ongoing process. They coordinate activity across scales because persistence depends upon interactions extending beyond any single spatial or temporal domain.

APS therefore replaces the search for a privileged unit with an explanatory grammar grounded in organised persistence.

This framework is not introduced as a classificatory scheme but identified as the minimal structure required for explanatory adequacy. Without agency, normativity disappears; without process, organisation becomes static; without scale, coordination across time and space cannot be explained; without organised persistence, these dimensions remain disconnected and fail to explain what is distinctive about living systems.

APS therefore identifies the organisational conditions that biological explanation must ultimately account for.

Within this framework, biological normativity emerges from the conditions required for continued viability. Living systems do not require externally imposed goals or observer-defined purposes. Conditions become biologically significant because they affect the persistence of organised activity itself. Evaluation, regulation, adaptation, function, and teleonomy therefore arise from the organisational requirements of continuity rather than from standards imposed upon the system from outside.

APS therefore replaces the search for a privileged unit with an explanatory grammar grounded in distributed organisation and continuity-preserving persistence.

It also reframes causation. Rather than treating causation solely as the production of events, APS understands biological causation as the viability-oriented modulation of constraints within organised systems. Mechanistic interactions remain essential, but they are situated within organisation that sustains the conditions under which those interactions remain viable (see Biological Causation — From Mechanism to Organised Persistence).

Mechanisms explain how particular biological activities occur. Organised persistence explains why those activities contribute to the continued viability of the system. Mechanistic and organisational explanations are therefore complementary rather than competing forms of understanding.

APS, Evolution, and Organised Persistence

The APS explanatory grammar reveals a complementary relationship between biological organisation and evolutionary theory.

Evolutionary theory explains how populations of organisms change through time through processes such as variation, inheritance, selection, drift, and ecological interaction.

APS addresses a different but equally fundamental question: how viability-oriented organisation is maintained in the first place.

Before variation can be inherited or selected, there must already exist systems capable of maintaining organised persistence across time. Organisms must sustain viability long enough to reproduce. Developmental systems must regenerate organisational structure across generations. Ecological conditions must support the continuation of living organisation.

APS therefore does not compete with evolutionary theory. Rather, it provides an explanatory framework for understanding the organised systems upon which evolutionary processes operate.

APS explains the organisation that persists.

Evolution explains the transformation of that organised persistence through time.

The two frameworks therefore address complementary dimensions of biological explanation: one concerned with the maintenance of viability-oriented organisation, the other with its historical transformation.

Why This Grammar Matters

By making explanatory grammar explicit, APS clarifies core biological questions. It specifies what counts as a biological individual, how organisms regulate their internal conditions, how evolution transforms organised systems, and how cognition emerges from biological activity.

Explanation is thereby grounded not in isolated components or privileged scales, but in viability-oriented organisation sustained through interacting processes across scales.

This shift has important consequences.

Biological individuality becomes a question of continuity-preserving organisation rather than static material composition.

Biological causation becomes a question of how constraints are organised and modulated within viable systems.

Function becomes a question of contribution to organised persistence rather than externally assigned purpose.

Cognition becomes a specialised elaboration of biological organisation rather than the conceptual foundation from which biological explanation must begin.

Across these domains, APS seeks to explain life in terms of the organisational conditions that allow living systems to maintain themselves despite continual change.

Explanatory Grammar and Scientific Practice

Scientific explanation necessarily employs conceptual categories that render complex phenomena intelligible. These categories are indispensable, yet they can also become invisible. When this occurs, elements of an explanatory grammar may come to appear as intrinsic features of reality itself rather than as components of a particular explanatory framework.

In biology, this tendency has repeatedly generated debates concerning the fundamental units and causes of life. Genes, cells, organisms, populations, networks, developmental systems, and ecological communities have each been proposed as privileged explanatory centres. Yet these disputes often persist not because of conflicting evidence, but because different explanatory grammars prioritise different aspects of biological organisation.

APS suggests that many long-standing controversies in biology are therefore best understood as disagreements about explanatory grammar rather than disagreements about empirical facts. Different traditions frequently illuminate genuine features of living systems while simultaneously elevating particular explanatory categories to positions of explanatory priority.

This insight also helps clarify a number of familiar philosophical debates. Reductionism, emergence, mechanism, holism, and organicism need not be understood as mutually exclusive accounts of life. Each highlights important aspects of biological organisation while operating within a particular explanatory orientation. Their apparent incompatibilities often arise from differences in explanatory grammar, explanatory direction, or explanatory scale.

APS does not seek to eliminate these perspectives. Rather, it provides a broader explanatory framework within which they can be understood as complementary descriptions of viability-oriented organisation.

The central question therefore shifts. Instead of asking which entity, mechanism, process, or scale is fundamentally responsible for life, APS asks how organised persistence is achieved and maintained. Biological explanation becomes the study of the organisational conditions under which living systems sustain themselves through continual transformation.

Living systems are not defined by a privileged component. They are continuity-preserving organisations maintained through distributed and interacting processes. Explanation must therefore track this organisation rather than reduce it to any single explanatory domain.

APS provides an explicit explanatory grammar capable of doing so.

Where to Go Next

To see how this explanatory grammar is developed within the APS framework:

Explanatory grammar is not an additional component of biology. It is the conceptual structure through which biological phenomena become intelligible. By making that structure explicit, APS seeks to clarify how living systems can be understood as viability-oriented organisations that persist, transform, and evolve through time.