Consciousness is not a mere byproduct of brain activity but has a function: subjective experience carries intrinsic value that motivates action. The authors propose the 'phenomenal worthiness' hypothesis, arguing that agents act because they experience and care about those experiences. This value-laden quality allows comparison of different experiences in a unified, subject-centered space, explaining why consciousness feels unified. If phenomenal experience has intrinsic value, then consciousness must have a function, making the hard problem of consciousness more tractable by reframing it as a problem about function.
Phenomenal experience—what it feels like to be an organism—has intrinsic value that cannot be reduced to evolutionary cost-benefit calculations. While all organisms act for reasons shaped by extrinsic evolutionary pressures, some also act for reasons of their own, sometimes even in ways detrimental to their survival. This shift marks a fundamental change in nature: subjective experience broadens an organism's capacity to act not merely in response to objective evolutionary value but also according to preference-driven subjective value associated with items, situations, events, or other agents. Subjective value can serve both as a driver of behavior and as a target for behavior, making it irreducible to extrinsic forms of value.