Abstract
A platonic theory of possibility states that truths about what’s possible are determined by facts about properties not being instantiated. Recently, Matthew Tugby has argued in favour of this sort of theory, arguing that adopting a platonic theory of possibility allows us to solve a paradox concerning alien properties: properties that might have been instantiated, but aren’t actually. In this paper, I raise a worry for Tugby’s proposal—that it commits us to negative facts playing an important truth-making role—and offer a strategy to avoid the objectionable negativity.