Although I have little sympathy for Nagel's instrumentalism, his "dictum" on the debates over scientific realism (as Boyd refers to it) is disconcertingly accurate; it does seem as if "the already long controversy...can be prolonged indefinitely." The reason for this, however, is not that realists and instrumentalists are divided by merely terminological differences in their "preferred mode[s] of speech", indeed, this analysis appeals only if you are already convinced that realism of any robust sort is mistaken. The debates persist, instead, (...) because the most sophisticated positions on either side now incorporate self-justifying conceptions of the aim of philosophy and of the standards of adequacy appropriate for judging philosophical theories of science. Realism and anti realism thus confront one another as preferred and essentially incommensurable modes of philosophical practice; it is in this sense that they have "dialectical resources for maintaining [their positions] in face of [virtually any] criticism." In what follows I first give an analysis of the central forms of argument for realism and anti realist responses to them that shows how the locus of debate has shifted to metaphilosophical issues. This is the basis for characterizing and assessing the forms of philosophical practice that are now emerging; my thesis is that there are strong grounds for preferring realism if the competing positions are judged as comprehensive research programs. (shrink)