 Thus, if we accept Quine’s general picture of knowledge, it becomes quite difficult to disentangle normative from descriptive issues, or questions about the psychology of human belief revision from questions about the justifiability or rational defensibility of such revisions. It is in part for this reason that Quine famously suggests (1969, 82; see also p 75–76) that epistemology itself “falls into place as a chapter of psychology and hence of natural science”: the point is not that epistemology should simply be abandoned in favor of psychology, but instead that there is ultimately no way to draw a meaningful distinction between the two. (James Woodward, in comments on an earlier draft of this entry, pointed out that this makes it all the harder to assess the significance of Quinean underdetermination in light of Laudan’s complaint or even know the rules for doing so, but in an important way this difficulty was Quine’s point all along!) Quine’s claim is that “[e]ach man is given a scientific heritage plus a continuing barrage of sensory stimulation; and the considerations which guide him in warping his scientific heritage to fit his continuing sensory promptings are, where rational, pragmatic” (1951, 46), but the role of these “pragmatic” considerations or principles in selecting just one of the many possible revisions of the web of belief in response to recalcitrant experience is not to be contrasted with those same principles having a rational or epistemic justification. Far from conflicting with or even being orthogonal to the search for truth and our efforts to render our beliefs maximally responsive to the evidence, Quine insists, revising our beliefs in accordance with such pragmatic principles “at bottom, is what evidence is” (1955, 251). Whether or not this strongly naturalistic conception of epistemology can ultimately be defended, it is misleading for Laudan to suggest that the thesis of underdetermination becomes trivial or obviously insupportable the moment we inquire into the rational defensibility rather than the mere logical or psychological possibility of alternative revisions to the holist’s web of belief. 