  Numerous feminist social epistemologists, particularly those working in philosophy of science, have employed the underdetermination thesis to argue for the necessary role of background assumptions in theory choice (Anderson 1995b; Longino 1990, 2002; Nelson 1990; Potter 1996). If theory is underdetermined by the data, and multiple theories can always explain the data equally well, then data alone cannot determine the best theory. Background assumptions must be employed as well. The problem is that background assumptions, which may include methodological assumptions, assumptions with empirical content, metaphysical assumptions, and value-laden assumptions, are rarely articulated. They may also be gendered, or otherwise shaped by culturally salient social identity categories. Drawing attention to the necessary role of these often unarticulated assumptions has allowed feminist philosophers of science to explain both how androcentric and sexist assumptions have managed to persevere for so long in science, as well as why feminist values do not have to be eliminated from scientific research in order for it to constitute good science. But in order to make epistemic distinctions and continue to claim that some theory choices are better than others, they must explain how we are to sort through and select those background assumptions we are willing to rely on.