This paper investigates the applicability of reliabilism to scientific knowledge, and especially focuses on two doubts about the applicability: one about its difficulty in accounting for the epistemological role of scientific instruments, and the other about scientific theories. To respond to the two doubts, we extend virtue reliabilism, a reliabilist-based virtue epistemology, with a distinction of two types of epistemic virtues and the extended mind thesis from Clark and Chalmers (Analysis 58:7–19, 1998 ). We also present a case study on (...) the quantitative research methodology of social sciences to show that the methodology is actually an extended virtue reliabilism on how social science instruments and theories contribute to the formation of social scientific knowledge. (shrink)