Structural Emergence of Intelligence (SEI) v1.2: Planetary-Scale Structural Conditions for the Emergence of Intelligence

We present SEI v1. 2 (Structural Emergence of Intelligence), a minimal and falsifiable framework that extends the emergence of intelligence from galactic to planetary scales. In SEI, intelligence is not treated as a biological accident, but as an emergent phenomenon arising from the self-referential stabilization of structured information under persistent differentiation. The framework is defined by three key variables: - structural density C (x, t) - information fixation rate Γ (x, t) - structural persistence dSC/dt Intelligence is proposed to emerge when these variables simultaneously exceed critical thresholds. Previous versions of SEI established spatial and temporal constraints at galactic scales. In SEI v1. 2, we introduce a planetary structural emergence window, demonstrating that not all habitable planets produce intelligence. We show that intelligence requires a narrower balance of: - environmental complexity, - stable information fixation, - long-term persistence. This leads to a central prediction: Not all habitable planets produce intelligence. We distinguish between: - a broad habitable zone (supporting life), - a narrower structural intelligence zone (supporting intelligence). This distinction provides a testable and falsifiable hypothesis linking planetary environments to intelligence emergence. The framework is supported by: - a structural condition map (Fig. 7), - a planetary case study (Earth, Fig. 8), - a probabilistic distinction between habitability and intelligence (Fig. 9). SEI v1. 2 provides: - a minimal structural definition of intelligence, - a planetary-scale emergence condition, - a falsifiable prediction about the rarity of intelligence, - a bridge between astrobiology, planetary science, and complex systems. If observations show that intelligence is equally common across all habitable planets, or that planetary structure does not correlate with intelligence emergence, the framework is falsified. This work proposes that intelligence is not random, but structurally constrained. A testable framework explaining why not all habitable planets produce intelligence