In this important new work, Haack develops an original theory of empirical evidence or justification, and argues its appropriateness to the goals of inquiry. In so doing, Haack provides detailed critical case studies of Lewis's foundationalism; Davidson's and Bonjour's coherentism; Popper's 'epistemology without a knowing subject'; Quine's naturalism; Goldman's reliabilism; and Rorty's, Stich's, and the Churchlands' recent obituaries of epistemology.