Abstract
Quine's conception of philosophy, his doctrine of naturalism, is analyzed as springing from a negative side, the rejection of first philosophy, through holism and unregenerate realism, and leading to an affirmative side, the acceptance of science as the ultimate instance. Quine's position is compared with Lauener's pragmatic or open transcendentalism, which is conventionalist and explicitiy nonnaturalistic but in spite of a whole string of differences nevertheless similar to the former. Finally a naturalistic position gains preference because it has more explanatory power and a purely conventionalist account of logic (and mathematics) seems quite unrealistic.