  The basic structure of this argument derives from Alvin Plantinga's argument from his (1983) against what he called existentialism, the thesis that all individual essences are dependent upon the individuals that instantiate them. Plantinga concluded that a singular proposition about o can exist even though o does not exist. (See in particular (1983, 8–9), where he argued that the notion of constituency is too confused to allow us to conclude that the constituent of a singular proposition must exist in a world for that proposition to exist in that world.) Plantinga also argued that the property being identical to o can exist without o, even though that property is constructed by λ-abstraction from the proposition [o is identical to o]. Plantinga would have been much better served, we believe, by denying that propositions like (7) are singular propositions, on the grounds that, if they were, they would not be possibly true. Instead, propositions like (7) contain individual essences as constituents. (Plantinga should not conceive of an individual essence as constructs form an individual identity property, as that property is dependent on the individual that instantiates it. Instead, an individual essence is either a primitive property stipulated to be necessarily related to the individual whose essence it is or would have been that can nonetheless exist unexemplified or the rigidification of some condition that the individual uniquely satisfies, following Plantinga's response to the modal argument above in section 2.) Let H be such an individual essence of Bush. Then (7) is true just in case H is uninstantiated, the proposition [Bush is president] is true just in case H and the property being president are coinstantiated, etc.. The pay-off is that (7)'s being true in a possible world does not violate (P1) and (P2), as there are possible worlds in which Bush's individual essence exists but is unexemplified.