Integrated Information Theory: Quantifying Consciousness via Cause-Effect Structures and Phi — E8 Intelligence Research

Abstract

FINDING: IIT formalizes consciousness as integrated information Φ, measured via the cause-effect structure of a physical system, with mathematical constraints on irreducibility and exclusion. | MATH: Φ (phi) = integrated information, computed as the minimal Earth Mover's Distance (EMD) between the cause-effect repertoire of a system and its partitioned parts; IIT 3.0/4.0 uses the PyPhi algorithm (exponential complexity, NP-hard in general); core axioms: existence, composition, information, integration, exclusion; postulates: intrinsicality, composition, information, integration, exclusion. Key constants: none intrinsic, but Φ is a real-valued scalar (≥0); maximal Φ (Φ^max) defines the "major complex." | CONNECTION: The symbol Φ (phi) is shared with the golden ratio conjugate (0.618…), but IIT's Φ is a distinct mathematical quantity — no direct geometric ratio link. However, IIT's cause-effect structure is a directed graph with symmetries; the "exclusion" postulate selects a unique maxi Author: Andrew Stewart Caldin, Independent Researcher, UK. Part of the E8 Intelligence Research series. Platform: e8intelligence.com