  The point here is that Quine denies that there is a distinctively philosophical standpoint, which might, for example, allow philosophical reflection to prescribe standards to science as a whole. He holds that all of our attempts at knowledge are subject to those standards of evidence and justification which are most explicitly displayed, and most successfully implemented, in the natural sciences. This applies to philosophy as well as to other branches of knowledge. The epistemologist, therefore, reflects on science from within science; there is no theory of knowledge distinct from science. “Epistemology”, Quine says, “…is contained in natural science, as a chapter of psychology” (1969, 83). (For an alternative view of the relation of philosophy to science, based on discussion of the history of science, see Friedman, 1997.)