W.V.O. Quine declared more than once that he was a naturalist. This claim must not be limited to one or another field of philosophy but should be understood as pertaining to every possible aspect philosophy. In ontology Quine wrote about 'ontological commitments of theories', in philosophy of logic he spoke of 'existence being a value of a variable', in semantics he opted for 'semantic behaviorism', and in epistemology he urged to 'make do with psychology'. The author concentrates on Quine's epistemology and shows how his views were different from other positions held in that field. The common key is naturalization. This view is supported by showing how Quine responded to his critics. To fend off skeptical doubts he argues that sceptical doubts are to be placed within science and not used as an external criterion of its results. When defending himself against the acusation that he eliminated all normative claims from science, Quine argued that axiological investigation have ultimately a scientific character. Finally when he proposed to naturalize epistemology his justification was based on the concept of holism, which was to be construed as one more plank in the naturalisatic boat that must be repaired at open sea, in his favorite metaphore invented by Neurath.