 Of course, generating and testing fundamental scientific hypotheses is rarely if ever a matter of finding curves that fit collections of data points, so nothing follows directly from this mathematical analogy for the significance of contrastive underdetermination in most scientific contexts. But Bas van Fraassen has offered an extremely influential line of argument intended to show that such contrastive underdetermination is a serious concern for scientific theorizing more generally. In The Scientific Image (1980), van Fraassen uses a now-classic example to illustrate the possibility that even our best scientific theories might have empirical equivalents: that is, alternative theories making the very same empirical predictions, and which therefore cannot be better or worse supported by any possible body of evidence. Consider Newton’s cosmology, with its laws of motion and gravitational attraction. As Newton himself realized, van Fraassen points out, exactly the same predictions are made by the theory whether we assume that the entire universe is at rest or assume instead that it is moving with some constant velocity in any given direction: from our position within it, we have no way to detect constant, absolute motion by the universe as a whole. Thus, van Fraassen argues, we are here faced with empirically equivalent scientific theories: Newtonian mechanics and gravitation conjoined either with the fundamental assumption that the universe is at absolute rest (as Newton himself believed), or with any one of an infinite variety of alternative assumptions about the constant velocity with which the universe is moving in some particular direction. All of these theories make all and only the same empirical predictions, so no evidence will ever permit us to decide between them on empirical  grounds.[7]