Abstract

The antirealist argument from the underdetermination of theories by data relies on the premise that the empirical content of a theory is the only determinant of its belief-worthiness (premise NN). Several authors have claimed that the antirealist cannot endorse NN, on pain of internal inconsistency. I concede this point. Nevertheless, this refutation of the underdetermination argument fails because there are weaker substitutes for NN that will serve just as well as a premise to the argument. On the other hand, antirealists have not made a convincing casefor NN (or its weaker substitutes) either. In particular, I criticize van Fraassen's recent claim that all ampliative rules in epistemology must be rejected on the grounds that they lead to incoherence. The status of the underdetermination argument remains unsettled.