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.

My first degree was in mathematics. That was great, but it didn't help with many of the things that puzzled me. I became a philosopher because I wanted to understand everything, especially those things that didn't make sense. And that has continued to be my philosophical motivation. That's one reason I have such a roving philosophical eye - once I have figured out a philosophical topic to my satisfaction, I find myself moving on to new problems.

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.

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.

I don't have much use for the concept of innateness. The everyday concept incorporates a number of different notions that can come apart in in many ways, and as a result encourages a range of dangerously fallacious inferences.

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.

Philosophers sometimes also use 'reductionist' more strictly, to mean 'type-identities' between mental and physical categories, and to exclude 'non-reductive physicalisms' like metaphysical functionalism.