Understanding the Diagram
This interactive diagram plots systems across two fundamental axes:
- SdW (X-axis): A measure of a system's metabolic and propagative capacity. High SdW indicates robust, self-sustaining chemical flux and growth.
- Information Index (I) (Y-axis): A measure of a system's heritable information content and complexity (e.g., genome size and function).
Hover over the points to explore examples within each of the four emergent regimes of existence.
The "Lion Problem" & Its Resolution
The initial Life Index Equation (LIE) was a bold, "lion"-like assertion that a single number (SdW > 1) could define life. However, it faced critical challenges:
- Arbitrary Thresholds: The normalization constants used to calculate SdW seemed subjective, not universal.
- Measurement Ambiguity: It was unclear precisely what to measure for "flux" or which "boundary" to consider in complex organisms.
- The "Zero Problem": The equation's multiplicative form meant that a sterile but clearly living organism (like a mule) would be classified as non-living (SdW=0) due to a zero individual propagative rate.
These critiques led to the evolution of the LIE into the more robust Life Phase-Diagram Hypothesis (LPDH). This reframing introduced key solutions:
- Context-Dependent Thresholds: Recognizing that the SdW=1 boundary is a regime classifier, not a fixed constant, similar to the Reynolds number in fluid dynamics.
- Modular & Redefined Pillars: Clarifying measurements and crucially, redefining propagation (Π) as "compartmental propagation" (a population can propagate even if an individual cannot).
- The SdW-I Phase Space: Moving from a single number to a 2D plot, integrating metabolism (SdW) and information (I) to resolve paradoxes and unify "metabolism-first" and "genetics-first" origin-of-life theories.