 Callender goes on to point out that once we grant that the Lorentz interpretation is logically consistent and empirically adequate, the question becomes, “[w]hat are a few lost explanatory virtues in contrast to _______ (fill in the blank with whatever tenses explain)?” (2008: 53). After all, we have to posit an unobservable frame of reference and we don’t, typically, posit unobservables without good reason. At the moment, we lack good reason, unless we think that the motivations for presentism (e.g., those described in  §2)  serve to persuade us that a neo-Lorentzian interpretation of the physics of space-time is preferable to the space-time interpretation. Undermining thus looks to be a difficult road to plough.