 We conclude this section by briefly discussing issues that arise with the interaction between quantifiers, tense and modal operators, and a universal, first-order existence predicate, as this interaction is the source of another important cost of the account of existence being outlined in this section. There are two sets of intuitions that seem to pull in opposite directions.  The first concerns the transience and contingency of existence. Things seem to come in and go out of existence through time. While Plato and Descartes used to exist, they no longer do; when Plato existed, Descartes did not yet exist; and right now the first child to be born in 2150 does not exist, but that individual will. So, it seems, different things exist at different times. Likewise, of the things that in fact exist, it seems that some of them might not have existed at all and different things—things that in fact do not exist—might have existed instead or in addition. So, it seems, different things exist at different worlds. These intuitions are quite robust. The second set of intuitions concern the ontological status of nonactual and nonpresent objects. Many philosophers are drawn to the thesis of actualism: The thesis that absolutely everything is actual and how an object is simpliciter is how it actually is, unactualized possibilities for an object being in some sense hypothetical ways of being for that object. While less popular, many philosophers accept the temporal analog of actualism, the thesis of presentism, according to which absolutely everything is present and how an object is simpliciter is how it presently is, how an object was and will be are in some sense hypothetical ways of being for that object. These two sets of intuitions combined with the view of existence under consideration in this section lead to difficulties.