 The foregoing principles implicitly characterize both abstract and ordinary objects. Zalta’s theory doesn’t postulate any concrete objects, though, since that is a contingent matter. But his system does include the Barcan formula (i.e., \(\Diamond \exists xFx \to \exists x\Diamond Fx\)), and so possiblity claims like “there might have been talking donkeys” imply that there are (non-concrete) objects at our world that are talking donkeys at some possible world. Since Zalta adopts the view that ordinary properties like being a donkey necessarily imply concreteness, such contingently nonconcrete objects are ordinary.