  However, some work on actualism (Menzel, 1990)  tends to undermine this objection. For example, Linsky and Zalta (1994) and Williamson, (2013) argue that the fixed-domain quantifier can be given an interpretation that is perfectly acceptable to actualists. Pavone (2018) even contends that on the haecceitist interpretation, which quantifies over individual essences, fixed domains are required. Actualists who employ possible worlds semantics routinely quantify over possible worlds in their semantical theory of language. So it would seem that possible worlds are actual by these actualist’s lights. By populating the domain with abstract entities no more objectionable than possible worlds, actualists may vindicate the Barcan Formula and classical principles. 