On the transitional character and regularity of planetary abiogenesis

The emergence of biology from planetary chemistry remains one of the central open questions in planetary physics, chemistry and biochemistry. In this study, we address an important aspect of this problem: whether abiogenesis is a statistically regular process under broadly defined planetary conditions, or a unique, highly contingent event. To examine it, we introduce a conceptual framework of regularity-relevant classes of adaptive planetary physico-chemical systems: the adaptability ladder model, that formalizes the progression from chemically rich but unorganized environments to stable biochemical systems. The model provides a structured approach to the regularity question, examining potential constrains and bottlenecks in specific adaptive classes and formulate formal statements of the regularity hypothesis: specialized for individual classes and strong (or general) across the full adaptive spectrum. We then assess their differential detectability across observation channels: laboratory simulation, in situ exploration, and remote sensing. Our analysis reveals a strong complementarity between detection channels and the regularity classes, with fragile proto-biotic states accessible primarily through laboratory studies. We observe that under the regularity hypothesis, such early adaptive states should emerge reproducibly under appropriate simulated planetary conditions. This result establishes a direct and testable link between laboratory experimentation and the general question of the regularity of biological emergence, positioning lab-based studies as central to future progress. The framework extends conventional definitions of planetary habitability, traditionally focused on terrestrial-class physical and chemical conditions by incorporating informational aspects, specifically compositional and interactive diversity. This broader perspective informs the strategic prioritization of empirical search efforts, bridging theoretical insights with observable planetary conditions.