The Feeling of Life Itself: Why Consciousness Is Widespread but Can't Be Computed: Summary & Key Insights

The history of consciousness studies is a chronicle of our evolving humility before the unknown. From Descartes’ dualism to modern neuroscience, we have oscillated between seeing mind as separate from matter and idealizing it as an emergent computation. Philosophers debated whether subjective experience could ever be captured by objective science. Meanwhile, neuroscientists mapped the brain, tracing neural activity with astonishing precision, yet still failing to uncover the 'spark'—the point at which sensation becomes experience. I came to see that a purely reductionist approach, taking the brain apart until consciousness disappears into smaller parts, cannot explain the whole. Consciousness is not an epiphenomenon that hovers above the neurons—it is woven into the causal fabric of physical existence itself.

Integrated Information Theory emerged from deep reflection on what we actually mean when we say 'experience'. Rather than starting with brain data alone, IIT begins with phenomenology—with the irreducible facts of what it is like to be. Every conscious experience is specific, unified, structured, and definite. From these axioms, we can reason about what kind of physical systems could realize them. IIT’s central quantity, Φ (phi), measures the amount of integrated information generated by a system. A system that cannot be decomposed into independent parts without losing causal power, one that generates more information as a whole than the sum of its parts, possesses consciousness to the extent of its integrated structure. This provides a scientific way to link physical mechanisms to subjective experience, not by simulation but through intrinsic causation.