A certain kind of methodologically-minded philosopher of science is quick to read off metaphysical conclusions from features of scientific practice. Chemists don't derive their laws from fundamental physics, so reductive physicalism must be false. Biologists refer to natural numbers in some of their explanations, so numbers must exist. I think that this kind of thing makes for bad philosophy.

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.

On the methodological issue, I think that would be hopeless to try to adjudicate between my view and orthodoxy by appeal to phenomenological introspection. We need to know about brain mechanisms.

I think that there are non-physical laws all right: genuine (if not strict) laws written in the language of biology, economics, and so on. But I don't regard that as a contentious issue. Even reductionists about chemistry will think that there are special chemical laws whose formulation makes essential use of chemical terminology.

A certain kind of methodologically-minded philosopher of science is quick to read off metaphysical conclusions from features of scientific practice. Chemists don't derive their laws from fundamental physics, so reductive physicalism must be false. Biologists refer to natural numbers in some of their explanations, so numbers must exist. I think that this kind of thing makes for bad philosophy.

I don't think that we are capable of anything like this many possible colour responses. Instead I argue that the perception of colour differences between two surfaces viewed side-by-side is a gestalt phenomenon.

The 'phenomenal concept' issue is rather different, I think. Here the question is whether there are concepts of experiences that are made available to subjects solely in virtue of their having had those experiences themselves. Is there a way of thinking about seeing something red, say, that you get from having had those experiences, and so isn't available to a blind person?