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?

I do have quite a lot of sympathy for Fodor's picture of concepts as information-free atomic entities which get locked onto their referents causally, and to that extent they needn't involve anything much in the way of learning. But even so it seems perverse to call them 'innate'. Here we see again the oddity of treating 'not learned' as sufficient for innate.

I rather incline towards 'conceptualism', in line with my view of colour perception - I don't think that we can represent objects and properties for which we have no concepts, not even in perceptual experience. In this sense I differ from those who defend 'non-conceptual content' like Michael Tye and Chris Peacocke.

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.

In truth a clear-headed physicalist shouldn't be thinking any of these dualist thoughts. If pains are one and the same as C-fibres firing, then there really isn't any possibility of having 'one' without the 'other'. Once you properly appreciates physicalism, this dissociation should cease to appear possible - C-fibres with pains should strike you as no more possible than squares without rectangles.

Of course, there remains the question of why we should find mind-brain identities so persistently counter-intuitive, if they are true. But this is a simple psychological question, and there are a number of plausible explanations. Indeed this is a topic that is quite extensively discussed outside philosophy, by developmental psychologists and theorists of religion among others, under the heading of 'intuitive dualism'. It is rather shocking that so few of the many philosophers working on 'the explanatory gap' are familiar with this empirical literature.

After all, in supporting phenomenal concepts I am in a sense siding with introspection against the more behaviourist Wittgensteinians. But even so I don't think that introspection is powerful enough to resolve the specific issue about how many colours you can see.