Introduction

Scientific frameworks are often presented as collections of concepts, models, and explanations. Terms are introduced, definitions are offered, and relationships are implied. Yet in many cases, these elements remain only loosely connected, allowing meanings to shift across contexts.

APS takes a different approach.

In APS, definitions are not independent descriptions but components of an organised explanatory system. Their role is not only to describe biological phenomena, but to stabilise the conceptual structure through which those phenomena are understood.

This article establishes the general principle that APS concepts form a system of mutually constraining definitions. The specific structure of that system, as realised in the glossary, is addressed separately.

Conceptual Closure and the APS Glossary

Beyond Isolated Definitions

In much of biology, key terms—such as life, function, adaptation, or information—are used with varying meanings across different contexts. This flexibility can be useful in informal discussion, but it introduces ambiguity in explanation.

When definitions are not tightly connected, explanations can shift without notice. Different assumptions may be introduced implicitly, leading to inconsistencies that are difficult to detect.

APS addresses this by treating definitions as interdependent.

Each term is defined in relation to others within a shared conceptual framework. Changing one definition therefore has consequences for the system as a whole.

Definitions as Conceptual Constraints

APS treats definitions as constraints within an explanatory system.

A constraint, in this context, is not a limitation imposed from outside, but a condition that stabilises organisation. Just as constraints in biological systems channel activity into coherent patterns, definitions in APS channel explanation into coherent form.

Definitions therefore do not merely label phenomena. They regulate how explanations can be constructed.

Conceptual Closure

In living systems, constraint closure describes the organisation of mutually dependent constraints that sustain persistence.

APS exhibits an analogous structure at the conceptual level.

Key definitions are mutually dependent. Concepts such as biological agency, process, scale, function, and adaptation are defined in ways that refer to and reinforce one another. Together, they form a network that stabilises explanation.

Conceptual closure therefore refers to a system in which definitions constrain and support one another, maintaining coherence across the framework.

Why Changes Propagate

Because APS definitions are interdependent, changes do not remain local.

If a definition is modified—especially at the level of foundational concepts—this can affect related terms throughout the framework. Maintaining coherence therefore requires that changes be evaluated in relation to the system as a whole.

This is not a weakness, but a consequence of integration. A tightly organised system requires that its components remain aligned.

Precision and Flexibility

APS distinguishes between two domains of language:

  • Explanatory language, where definitions must remain precise and stable
  • Descriptive language, where flexibility and variation are appropriate

The aim is not to restrict language in general, but to preserve clarity where explanation depends on it.

APS therefore distinguishes between canonical definitions and explanatory development. Definitions stabilise the system, while articles allow it to be extended, clarified, and refined without compromising coherence.

Why This Matters

Treating definitions as an organised system:

  • prevents conceptual drift
  • ensures consistency across explanations
  • allows knowledge to accumulate without ambiguity
  • makes assumptions explicit rather than implicit

This enables APS to function as a coherent explanatory framework rather than a collection of loosely connected ideas.

A General Implication

Although developed in a biological context, this approach has broader implications.

It shows how scientific frameworks can be organised as systems of mutually constraining concepts, rather than as sets of independently defined terms. Coherence is not assumed but actively maintained.

Conclusion

APS is not only a framework for understanding life. It is also an example of how explanation can be organised.

By treating definitions as interdependent constraints within a coherent system, APS maintains conceptual stability while allowing controlled development over time.

The glossary provides the concrete realisation of this structure. Together, principle and implementation form a unified conceptual system in which explanation is both constrained and generative.