In two recent papers, I criticized Ronald N. Giere's and Larry Laudan's arguments for 'naturalizing' the philosophy of science (Siegel 1989, 1990). Both Giere and Laudan replied to my criticisms (Giere 1989, Laudan 1990b). The key issue arising in both interchanges is these naturalists' embrace of instrumental conceptions of rationality, and their concomitant rejection of non-instrumental conceptions of that key normative notion. In this reply I argue that their accounts of science's rationality as exclusively instrumental fail, and consequently that their (...) cases for 'normatively naturalizing' the philosophy of science fail as well. (shrink)