We begin by taking “naturalism” in the sense in which P. F. Strawson (“Scepticism, Naturalism and Transcendental Arguments”, 1985) presented Wittgenstein’s anti-sceptical arguments as “naturalistic”. According to Strawson, this naturalism connects the philosophy of Wittgenstein with that of Hume. Then, we proceed to compare Hume’s and Wittgenstein’s positions and establish a tenet common to them, which we qualify as “meta‐philosophical”: philosophy rests on a bedrock that resists our demands of justification, a contingent “so we are, so we act” that is (...) beyond philosophical analysis. But this negative thesis leads to differentcommitments in each philosopher: a commitment with the autonomy of nature in the case of Hume, and a commitment with the autonomy of grammar in the case of Wittgenstein. Next, we analyze the epistemological implications of each commitment, particularly with reference to the status of natural science. We find a deep divergence between Hume and Wittgenstein on this point, so that the former, but not the latter, could still be labelled as “naturalist” in a positive, more substantial sense. Our central point here is the difficulty to give a naturalistic interpretation of such Wittgensteinian notions as “language game” or “form of life”. Finally, we stress that the distance between Hume and Wittgenstein is most clearly evidenced when we consider the normative (moral) implications of Hume’s concept of nature, which are completely absent from Wittgenstein’s approach, this being a feature of Wittgenstein’s philosophy that remained unchanged all along his work. (shrink)