There is no explanation of HOW mass generates or causes gravity, similarly for the lack of explanation of how matter causes or generates forces such as electromagnetism. (Yes I know that some sort of strings have been proposed to subserve gravity, and so far they seem to me to be another false "ether".) So in a shorthand of sorts, it is accepted that gravity and the various other forces exist as fundamentals ("axioms" of nature, if you will accept a metaphor), because their effects and interactions can be meaningfully applied in explanations. No one has seen gravity, no one can point to gravity--it is a fundamental force. Building on Chalmers in one of his earlier writings, I am willing to entertain the idea the qualia are a fundamental force-like dimension of consciousness. Finally every force is a function of something: gravity is a function of amount of mass, electromagnetism is a function of amount of charge. What might qualia and consciousness be a function of? Chalmers and others have suggested "bits of information", although that is an additional speculation.