Consciousness is not a single, all-or-nothing quality but a set of dimensions that evolved separately. By reverse-engineering their evolutionary functions, simpler valenced states likely arose first, with more complex phenomenological layers emerging later. This Darwinian approach reframes consciousness as phenomenological complexity. Support for this evaluation-first view comes from recent experimental philosophy of mind.
Biological evolution appears to increase complexity, but defining complexity is difficult. Measures that assign low complexity to both highly ordered and highly random systems and high complexity to intermediate systems show that most biological systems fall in this range. These measures quantify the information an organism stores about its environment, supporting the idea that evolution increases the knowledge organisms accumulate about their niche. This aligns with cognitive biology, which views evolution as a progressive accumulation of knowledge or epistemic complexity, resembling a cognitive ratchet pushing toward higher complexity. A dynamic environment creates problems to be solved, and each solution becomes embodied knowledge. The framework also links to integrated information theory, suggesting that human self-reflection marks a new qualitative level in epistemic complexity.