McGinn's materialism and epiphenomenalism

Colin McGinn urged that while a brain state P explains consciousness, a conception P is cognitively inaccessible to us. This paper argues that McGinn's argument for his form of materialism is committed to P being epiphenomenal or causally inert relative to such things as the movements of our bodies. As a result, McGinn's materialism creates a duality in the brain and thereby faces the same problem of epiphenomenalism which plagues the Cartesian dualist