Every objectively based theory of reality including or not its subjective doubling in consciousness (viewed objectively) incurs a dual theory which is its critical or idealist doubly and which simply traces every concept and mental move used in the first theory by way of its 'condition of possibility' as concept, its necessary appearance in thought prior to its application to the world. This epistemological move can be transposed into a metaphysical one since if the condition for everything knowable is that it first be knowable, why not simply say in the interest of parsimony that that's all there is or need be. The idealist dual theory, however, is just as much an objectivist one as the other, the mind that it presupposes is posited, deemed as present, to just the same degree as any primary elements of a naturalist theory. The true move to the subjective 'viewpoint' would take you out of theory altogether since it is to the subject that is you forever here and now. Here it can't be a theory but at most an 'understanding' - but in the same way as before, any such understanding has a dual (mis-)understanding which is more like a theory and generally goes by the name idealism.