 A theory of properties features unrestricted property abstraction provided that for any condition statable in the language of the theory, there exists a property that (according to the theory) is exemplified by precisely the things that meet this condition. Consider a theory \(\mathcal{T_P}\) formulated in a language with a property abstraction device \([x: \phi x]\) and an exemplification relation \(\epsilon\). For example, if \(\phi(t)\) says that the object which the term \(t\) stands for is triangular, \(t \ \epsilon \ [x: \phi x]\) says that this object exemplifies the property of triangularity. Then, given unrestricted property abstraction, we should have the following principle.