Underdetermination and Commonsense Realism

Abstract

This chapter defends commonsense realism against the underdetermination theses of extreme skepticism. If the theses were true, they would undermine almost all knowledge and thereby realism about the observable world. Traditional responses to these theses rest on a priori knowledge. The chapter rejects the a priori, but even if there were such knowledge, the traditional responses tend to involve bizarre metaphysics and are otherwise unsatisfactory. Instead, I offer a Moorean response: realism is much better supported than the epistemological theses that are supposed to undermine it. The Moorean response is further supported by a naturalistic one that appeals to scientific practice. Rather than proceeding from a priori epistemology to a priori metaphysics, it is better to start with empirical metaphysics and proceed to empirical epistemology. Put metaphysics first.