I don't think that we can figure out what is going on in conscious colour perception just by phenomenological introspection. We need to know about brain mechanisms as well. We need to figure out what information is present in the mechanisms that constitute conscious colour perception.

If there is such a simple argument for physicalism, how come everybody hasn't always been a physicalist? That's a good question, and there is a good answer. The 'causal completeness of physics' wasn't widely accepted until recently.

Again, when we view a scene fleetingly, do we consciously see all the details even though we don't retain them, or do we not see them in the first place? Neurological information is crucial to deciding these questions. After all, they are so interesting precisely because unaided introspection cannot resolve them. Rather we need to know what is going on in the brain activities that constitute visual awareness.

There is a brain mechanism that works to identify colour differences directly, without first identifying the absolute colour of each surface. So on my view there is no reason to suppose anything like ten million colour responses to surface viewed singly.

The orthodox view of colour experience assumes that, when we see a colour difference between two surfaces viewed side-by-side, this is because we have different responses to each of the two surfaces viewed singly. Since we can detect colour differences between something like ten million different surfaces, this implies that we are capable of ten million colour responses to surfaces viewed singly.

Of course our genes will make some capacities very much easier to learn than others, and of course our genes themselves are not learned. But the point remains that genes themselves are not cognitive capacities, and that anything worth calling a cognitive capacity will depend to some degree on learning and so not be innate.

Even if no learning to speak of was involved in locking my mental term onto doorknobs, it is odd to say that therefore my possession of a doorknob concept is innate, just as it is odd to say that my head-injury-caused singing is innate.