 As Armstrong notes (see also Fales 1990: 61 and French 2014), substitution of the determinable quantities \(F\), \(M\), and \(D\) with determinate values gives rise to “a law which stands as determinate to the original, determinable, law” (1997: 63). One might try to provide an anti-realist or reductionist treatment of these seemingly determinable laws. Armstrong (1997) argues, however, that such deflationary treatments cannot make sense of the role of functional laws in sustaining counterfactuals, at least if properties are Aristotelian universals, whose existence depends upon their being instantiated; for then there will typically (and perhaps necessarily, for the case of continuous quantities) be gaps in the actual instantiations of functional laws. As such, the unity of determinates in these cases involves not just partial identities (as discussed in  §3.4)  but “strictly identical second-order properties”, which are the “real […] determinables” (1997: 247). Functional laws of nature are then taken to be relations between these determinable universals.