The Building Blocks of Consciousness

Consciousness is presented not as a unified and uniquely human characteristic, but rather as an emergent property of several building blocks, most of which are demonstrably present in other species. Each block has its own rationale under natural selection and could have arisen independently, and the jumps between blocks -- which culminate in consciousness -- are small enough to be evolutionarily plausible. One underappreciated block involves unconscious engram playback and discrimination, and plays a major role in brain storage optimization. This function is present in birds and nearly all mammals and is recognized by its side-effect: dreams.