is necessarily true but a posteriori. If CT is the correct account of modal properties we still can keep the intuition that identity statements are contingent and a priori because counterpart theory understands the modal operator in a different way than standard modal logic. The relationship between CT and essentialism is of interest. (Essentialism, the necessity of identity, and rigid designators form an important troika of mutual interdependence.) According to David Lewis, claims about an object's essential properties can be true or false depending on context (in Chapter 4.5 in 1986 he calls against constancy, because an absolute conception of essences is constant over the logical space of possibilities). He writes: But if I ask how things would be if Saul Kripke had come from no sperm and egg but had been brought by a stork, that makes equally good sense. I create a context that makes my question make sense, and to do so it has to be a context that makes origins not be essential. (Lewis 1986:252.) Counterpart theory and rigid designators Kripke interpreted proper names as rigid designators where a rigid designator picks out the same object in every possible world (Kripke 1980). For someone who accepts contingent identity statements the following semantic problem occurs (semantic because we deal with de dicto necessity) (Rea 1997:xxxvii). Take a scenario that is mentioned in the paradox of coincidence. A statue (call it “Statue”) is made by melding two pieces of clay together. Those two pieces are called “Clay”. Statue and Clay seem to be identical, they exist at the same time, and we could incinerate them at the same time. The following seems true: (7) Necessarily, if Statue exists then Statue is identical to Statue. But, (8) Necessarily, if Statue exists then Statue is identical to Clay is false, because it seems possible that Statue could have been made out of two different pieces of clay, and thus its identity to Clay is not necessary. Counterpart theory, qua-identity, and individual concepts can offer solutions to this problem. Arguments for inconstancy Ted Sider gives roughly the following argument (Sider 2001:223). There is inconstancy if a proposition about the essence of an object is true in one context and false in another. C-relation is a similarity relation. What is similar in one dimension is not similar in another dimension. Therefore, the C-relation can have the same difference and express inconstant judgements