The legacy of the Platonic dialogues may well lie, not in any classical idealist “doctrine of forms,” but in an inquisitive stance towards the puzzle behind any such doctrine—how thought can be about anything at all. This Platonic puzzle may, however, yield a different guise of idealism that is recognizably diagnostic: it aims to dispel our worry about thought’s objectivity as a confusion, engendered by a self-alienation of thought. These themes of diagnosis and idealism resurface in Wittgenstein, who in his (...) treatment of rules calls for an understanding of thought’s normativity from within. This is taken up by Cora Diamond, who urges philosophy to attend to thought’s real needs by exorcizing any desire for agreement with something other than itself. I argue that Wittgenstein and Diamond lead us back to Kant’s idealism, which identifies transcendental realism as the deep-seated prejudice at the root of the puzzle. (shrink)