 Stanford (2001, 2006) concludes that no convincing general case has been made for the presumption that there are empirically equivalent rivals to all or most scientific theories, or to any theories besides those for which such equivalents can actually be constructed. But he goes on to insist that empirical equivalents are no essential part of the case for a significant problem of contrastive underdetermination. Our efforts to confirm scientific theories, he suggests, are no less threatened by what Larry Sklar (1975, 1981) has called “transient” underdetermination, that is, theories which are not empirically equivalent but are equally (or at least reasonably) well confirmed by all the evidence we happen to have in hand at the moment, so long as this transient predicament is also “recurrent”, that is, so long as we think that there is (probably) at least one such (fundamentally distinct) alternative available—and thus the transient predicament re-arises—whenever we are faced with a decision about whether to believe a given theory at a given time. Stanford argues that a convincing case for contrastive underdetermination of this recurrent, transient variety can indeed be made, and that the evidence for it is available in the historical record of scientific inquiry itself.