While naturalistic theories have come to dominate the philosophical landscape, there is still little consensus on what “naturalism” means. I trace the origins of contemporary naturalism to a view, called the “fundamental naturalistic impulse,” that originates in Quine’s turn against Carnap and which I take to be necessary for naturalism. In light of this impulse, some “substantively naturalistic” theories are examined: a weak version of non-supernaturalism, Railton’s a posteriori reduction of moral terms, and “Canberra plan” conceptual analyses of moral property terms. I suggest that if we take the fundamental naturalistic impulse seriously, then there is no need to differentiate substantive versions of naturalism over and above methodological versions. Substantive thesis in ontology or semantics can be had

on account of one’s methodological commitments. This not only cuts against the distinction between methodological and substantive naturalisms, but also demonstrates just how far method can reach.