 The obvious worry is that this meta-criterion for theories of scientific rationality threatens to deprive the philosophy of science of any critical bite. Will not the best philosophy of science simply say that whatever scientists do is rational, that scientific might is right, that the best methodology is Feyerabend’s “Anything goes”? Lakatos’s Kantian epigram “Philosophy of science without history of science is empty; history of science without philosophy of science is blind” threatens to eliminate the philosophy of science altogether, in favour of historical-sociological studies of the decisions of scientific communities. (One of us discusses this problem, and attempts to disarm the worry, in Musgrave 1983.)