 Objection 5: Geach remarks that “As for our recognizing relative identity predicables: any equivalence relation…can be used to specify a criterion of relative identity.” But §3 above contains a counterexample. Some equivalence relations are defined in terms of the I-predicable of a theory and hence cannot serve as such. (Any pair of I-predicables for a fixed theory are equivalent.) In fact it seems that any equivalence relation presupposes identity (cf. McGinn 2000). For example, the relation x and y are the same color presupposes identity of colors, since it means that there are colors \(C\) and \(C'\) such that \(x\) has \(C\) and \(y\) has \(C'\), and \(C = C'\). Identity, therefore, is logically prior to equivalence.