 The UN completion of naïve HD originated from Lakatos and some of his collaborators (see Lakatos and Zahar 1975 and Worrall 1978; also see Giere 1979, 161–162, and Gillies 1989 for similar views), although important hints in the same direction can be found at least in the work of William Whewell (1840/1847). Consider the touchstone example of Mercury again. According to Zahar (1973), Einstein did not need to rely on the Mercury data to define theory and auxiliaries as to match observationally correct values for the perihelion precession (also see Norton 2011a; and Earman and Janssen 1993 for a very detailed, and more nuanced, account). Being already known, the fact was not of course predicted in a strictly temporal sense, and yet, on Zahar’s reading, it could have been: it was “use-novel” and thus fresh for use to confirm the theory. For a more mundane illustration, so-called cross-validation techniques represent a routine application of the UN idea in statistical settings (as pointed out by Schurz 2014, 92; also see Forster 2007, 592 ff.). According to some commentators, however, the UN criterion needs further elaboration (see Hitchcock and Sober 2004 and Lipton 2005), while others have criticized it as essentially wrong-headed (see Howson 1990 and Mayo 1991, 2014; also see Votsis 2014). 