Abstract
When does science progress? I argue that recently proffered accounts of scientific progress are untenable. In contemporary discussions, a distinction between a scientific episode constituting progress and promoting progress is made: An episode may promote scientific progress even though it does not constitute scientific progress. By paying attention to scientific practice, in particular to scientists’ appraisal of developments in techniques and methodologies, I show that the constitution/promotion distinction is problematic. This is bad news for the extant accounts since virtually all the accounts appeal to the constitution/promotion distinction.
