Diagnostics and Empirical Tractability

APS_LD reframes life detection as the diagnostic identification of viability-oriented, constraint-closed biological organisation. Biosignatures and empirical observations are interpreted as evidence for organised, persistence-maintaining activity rather than as defining traits in themselves.

This article clarifies what counts as evidence for life in the APS framework. It distinguishes definition, diagnosis, and evidence, and shows that biological evidence is not behavioural but organisational—indicating viability-oriented, constraint-closed organisation across scale.

This article explains how biosignatures function within the Agency–Process–Scale (APS) framework as empirical indicators of viability-oriented organisation. Biosignatures do not define life, but provide observational evidence for organised, self-maintaining activity in contexts where direct perturbational diagnosis is impossible. APS reframes biosignatures organisationally rather than chemically, interpreting them as indirect indicators of persistence-sustaining processes.

Cognitive Integration (CI) is a core diagnostic dimension in APS, expressing the degree to which a system coordinates its activity across processes, time, and scale in sustaining its own viability. CI distinguishes simple reactive adjustment from integrated, system-wide regulation, but does not by itself constitute cognition, which additionally requires viability-oriented evaluation with temporal depth.

APS distinguishes between defining life and diagnosing its presence. The framework defines life ontologically as viability-oriented, constraint-closed organisation, but argues that recognising such organisation in practice requires diagnostic evaluation rather than trait-based classification. This article explains why APS approaches life as a diagnostic target revealed through perturbation, repair, persistence, and organisational failure.

This article applies the APS diagnostic framework to a plant system, demonstrating how viability-oriented organisation can be evaluated in practice. Using perturbation and the three diagnostic dimensions—Viability Gradient (VG), Normativity Gradient (NG), and Cognitive Integration (CI)—it shows how plant activity reveals biological agency without requiring neural or representational explanations.

APS distinguishes between malfunction within a system and the collapse of the organisation that sustains its viability. This article applies the APS diagnostic framework to cases of breakdown, showing how failure is identified when viability-oriented organisation can no longer be maintained across time and scale.

This article develops the methodological and empirical dimensions of APS diagnosis. APS diagnosis evaluates viability-oriented organisation through perturbation, regulation, evaluation, semiosis, and persistence-maintaining activity rather than through trait lists or static classification. Diagnosis in APS is explanatory, organisational, perturbational, and graded rather than merely classificatory.

The Normativity Gradient (NG) is a core diagnostic dimension in APS, expressing the degree to which a system’s activity is oriented toward sustaining its own viability. Rather than invoking intention or evaluation in a mental sense, NG captures the endogenous organisation through which systems differentiate between conditions that support or degrade persistence.

The Viability Gradient (VG) is a central diagnostic dimension in APS, capturing the degree to which a system sustains its own persistence under changing conditions. Rather than treating life as a binary property, VG provides a continuous measure of how effectively viability-oriented organisation is maintained across time and scale.

APS reframes biological diagnosis as the evaluation of viability-oriented organisation rather than the identification of traits, mechanisms, or components. This article defines diagnosis within the APS framework and clarifies how it differs from traditional biological and medical approaches.

In APS, malfunction refers to continuity impairment within organised persistence. Malfunction is not merely the failure of an isolated component, but the disruption of organisational relations required for sustaining viable continuity across interacting biological processes and scales.

In APS, resilience refers to the continuity-preserving capacity of living systems under perturbation. Resilience is expressed through regulation, compensation, recovery, adaptive flexibility, and organisational reorganisation that sustain viable persistence across changing conditions.