Introduction
The APS framework provides a unified account of life as viability-oriented, constraint-closed organisation. For new readers, the most direct way to understand this account is not to begin with definitions or comparisons, but with how APS approaches biological explanation.
APS explains life in two steps.
Step One: What Needs to Be Explained
The first step is to clarify the target of biological explanation.
Biology does not merely describe complex systems. It explains systems that sustain themselves. The article Biological Explanation — What Needs to Be Explained shows that biological explanation must account for viability-oriented, constraint-closed organisation: systems whose activity contributes to maintaining the conditions required for their own persistence.
This establishes what makes a system a living system and defines the central problem for biological explanation.
→ Read Biological Explanation — What Needs to Be Explained
Step Two: How Explanation Is Structured
The second step is to specify how such systems must be explained.
Once viability-oriented organisation is identified as the target, explanation must be organised accordingly. The article The Structure of Biological Explanation in APS develops this account. It shows that biological explanation requires the integration of agency, process, and scale, together with persistence, adaptation, evolution, and system–environment coupling.
This provides a unified explanatory grammar for understanding how living systems sustain and transform themselves across time.
→ Read The Structure of Biological Explanation in APS
From Entry to Exploration
These two articles provide the clearest entry into the APS framework. Together, they establish both what biology explains and how such explanation must proceed.
From this point, readers can explore how this explanatory structure operates across the framework, including physiology, adaptation, evolution, and system–environment relations.
Key Point
APS explains life by first identifying viability-oriented organisation as the target of biological explanation, and then specifying the explanatory structure required to account for it.