The Cross-Domain Coherence Index (CDCI): A Quantitative Framework for Unified Theory Validation Across Scientific Disciplines

The Cross-Domain Coherence Index (CDCI) is presented as a quantitative framework to evaluate theoretical models across multiple scientific disciplines for structural consistency, predictive alignment, and emergent property coherence. Unlike discipline-specific validation methods, CDCI operates by extracting the shared structural logic of a model and measuring its fit across independent domains, producing a normalized coherence score between 0 and 1. This approach allows for falsification, refinement, or reinforcement of a theory’s claim to universality. The CDCI is tested against multiple case studies from physics, biology, and cognitive science, including both high-coherence and low-coherence models, with results indicating its sensitivity to overfitting, domain misalignment, and theoretical incompleteness.