First Philosophy? Most of us will recall Quine's pronouncements on the subject: First Philosophy is the philosophical disease for which naturalism is the cure. Naturalism, the fifth and final milestone of empiricism, the cap crowning empiricism's triumphal arch, mandates the "abandonment of the goal of first philosophy," which is just to say that (Naturalism) sees natural science as an inquiry into reality, fallible and corrigible, but not answerable to any supra-scientific method, and not in need of any justification beyond observation and hypothetico-deductive method.1 By implication, First Philosophy subordinates natural science to "supra-scientific method" and to non-empirical constraints of justification. In the same passage, Quine notes that the sources of naturalism, thus understood, are two, and both negative: despair at the failure of attempts to define theoretical terms of science in terms of phenomena, with the resulting surrender to holism of empirical meaning, and secondly, an unregenerate realism, the robust state of mind of the natural scientist who has never felt any qualms beyond the negotiable uncertainties internal to science. According to Quinean naturalism, "the scientific epistemologist" has become a deckhand on Neurath's boat, adrift in a sea of incoming sensory stimulation, with only the planks provided by empirical psychology, the neurology of perception and of language learning, evolutionary theory, and so on, to refit the ever-evolving ark of contemporary scientific theory. Although few "scientific epistemologists"-if that term actually describes philosophers of science-have followed the letter of Quine's commandment to seek illumination of their perceived problems in the nitty-gritty details of cognitive psychology and evolutionary biology, the wider Quinean conception of naturalism has wide currency within philosophy of science. To be sure, from such passages as the one quoted some have puzzled that Quine would trouble to belabor what had been obvious since the time of Newton, that science was not to be yoked to a Cartesian (let alone Aristotelian) Prima Philosophia. But such objections miss the intended target of Quine's remarks. Penny Maddy, in a recent article enthusiastically endorsing Quinean naturalism, explicitly brings this out, quoting Quine himself: For the naturalist, there is no higher perspective, where transcendental or other extra-scientific considerations hold sway. The naturalist operates "from the point of view of our own science, which is the only point of view I can offer."2 We should not forget that the non-existent "higher perspective where transcendental or other extra-scientific considerations hold sway" includes the remnants of a constitutive but relativized a priori retained in the logical empiricists' recognition of conventionalist elements in scientific theories, in the analytic/synthetic distinction, and in particular in Carnap's conception of linguistic frameworks as a presupposition of inquiry. In any case, while naturalism would remain a subject of live debate within epistemological discussions per se, principally regarding the nature and sources of normativity, naturalism in Quine's broader sense, constraining philosophical reflections on science to lie within "the point of view of our own science," has long been the implicit ideology in the bulk of contemporary philosophy of science and in philosophy of physics. There are, of course, exceptions, of which the program formulated in Michael Friedman's Dynamics of Reason is by far the most articulated and influential.3 There, as against Quinean holism and Kuhnian relativism, it is shown how the cumulative and rational character of revolutionary change in mechanics and gravitational theory is accounted for by a continuous succession of meta-empirical a priori principles, "relativized" to particular theories. On the other hand, except by implication, within the frame of the Dynamics of Reason an explicit alternative is not posed to scientific realism, itself the inevitable outgrowth of the "unregenerate realism" of natural science that is, for Quine, one of two primary sources of naturalism. …