Epistemic dualism vs. Ontological monism

Habermas would in principle not contest the claim that even without humans “the universe would still consist of electrons etc.” However, Habermas’ route to this conclusion is different from our normal realist's (whom Habermas dubs rather peculiarly as a metaphysical realist). Habermas believes in what he calls epistemic dualism and ontological monism and his big question is how to reconcile this apparently exclusive positions. Habermas wants to avoid ontological dualism however he believes that epistemic dualism is a fact of our philosophical learning which cannot be wished away. From the perspective of our lifeworld and our subjective constitution we are compelled to use the categories that are “subjective” in order to understand the universe. This “produces” what we call objective universe. Objective universe would not have been possible without our subjective (or intersubjective) input. However, this is true only from the epistemic side of the story. Habermas also believes that the categories which we use to understand the universe attain an “objective” status if they prove their worth by cohering to our existing knowledge and resisting the onslaught of new experiences (if they don’t crumble in the face of new experiences they prove their worth). Obviously Habermas needs a strong notion of “experience” where by experience somehow contains an excess that overflows the bounds of our categories. Here, Habermas brings in his pragmatic conception of knowledge and his weak naturalism to support this notion of experience as excess and provide it both epistemological and ontological ground. What makes Habermas’ position intriguing and difficult to defend is that he wants to grab the best of the both worlds viz. epistemic dualism and ontological monism, idealism and realism.