 As this presentation should make clear, Culp’s account requires that robustness comes in degrees and that there should, therefore, be some way of comparing degrees of robustness. However, no proponents of robustness to date have been able to come up with such a measure. Ultimately, what the case of the mesosome shows is that, in realistic cases, the evidence for some theoretical entity is discordant (Stegenga 2009), meaning that some findings supported the existence of mesosomes whereas others did not. But this means that robustness as a criterion cannot give unequivocal results, unless there is some way of saying which body of data is more robust: the body that supported the theoretical entity or the body which did not. Thus, when the evidence is discordant the criterion of robustness fails to provide a solution to the problem of data reliability.