Back to the subject of qualia. Perhaps this way of looking at things best explains what my position is: A developing human brain gathers ever more experiences about the world it lives in. Every thought in the brain appears because of the interaction of brain cells with each other and with input from the senses. This direct mapping of thoughts to brain cell activity is of fundamental importance in understanding what it means to say we are conscious. It means that for every thought there are at least two ways of describing what is going on: at the level of thoughts, and at the level of brain cell activity. Both ways of describing what is happening are true, but one way may be more revealing at any given time. Anyway, as the brain develops thoughts may arise about the nature of conscious experience. Such a thought may be "what are these things which I shall call 'qualia'?". There are two interesting things happening here. One is that the brain now contains a concept of 'qualia', and the other is that there is a reason why the brain now contains that concept. Some process of thought, some reflection on experience, led to that concept.
The thing to remember is that all thoughts have an existence at the level of brain cell activity. What happens at that level is necessarily completely due to biology and so due to physics. There is no mysterious extra influence involved. And so, there is a complete explanation based on brain cell activity as to why the brain develops thoughts about conscious experience. and the concept of 'qualia' has a purely physical representation in brain states. Brain states can, of course, represent other things, including things that don't have physical existence, but for that representation of a thing to be correct, the brain has to contain true representations of the characteristics of that thing. For example, to have a correct representation of a dog, a brain must contain the information that a dog is a furry four-legged wolf descendant.
What about the characteristics of qualia does the brain have to represent for the concept of qualia to be correct? This is where the idea of qualia involving some extra property of the world runs into problems. How can a brain have a correct representation of the real property of something being more than just physics? Some say that qualia are something special because of what it feels like to have them. How can a brain truly represent that a feeling is that special? It can't. A brain can contain the belief that a feeling is special, but that belief can never be justified by evidence. That belief has no foundation other than a feeling of mystery.
This is my position: we can speculate all we like about the nature of consciousness, but we have to realise that our very thoughts have physical substance. There is no such thing as an internal sense of the non-physical, there is only the understandable feeling of mystery when we contemplate what it is like to be a self-aware being, and mystery says nothing about what is real.
[This is the core of the book that I hope to finish sometime... it's about what it means to be a human given what science has shown us about our place in the physical world.]