 Formal property theories are logical systems that aim at formulating “general noncontingent laws that deal with properties” (Bealer &amp; Mönnich 1989: 133). In the next subsection we shall outline how they work. In the two subsequent subsections we shall briefly consider their deployment in natural language semantics and the foundations of mathematics, which can be taken to provide further reasons for the acknowledgment of properties in one’s ontology, or at least of certain kinds of properties.