I don't think theory adds to criticism. (Methodology does, for better or worse.) Theory's function is to make criticism self-conscious, maybe even a little sheepish, about its ex cathedra pronouncements.
Paul FryThe rhetoric of theory is always in a bind. It pronounces ideas and denounces failures to accept or grasp them while insisting that there are no grounds either for accepting or grasping ideas.
Paul FryI do identify the escape hatch through which Foucault eludes the charge that he himself is an author/authority, hence a tyrant. He establishes the category of "founder of discursivity" for the authors he likes. Slippery, perhaps, but you can see what he means.
Paul Fry