  Like the new actualists, then, the metaphysics of the haecceitists enables  them to systematically reinterpret possible world semantics in such a  way that the truth conditions of modal discourse are expressed solely in term of actually existing entities of some sort rather than actual and non-actual individuals. More specifically, for the haecceitist,  the domain d(w) of a world w is taken to be the  set of haecceities that are exemplified in w, that  is, the set of haecceities h such that w includes  h's being exemplified. Likewise, the w-extension of a (1-place) predicate π is taken to be a set of  haecceities — intuitively, those haecceities that are  coexemplified in w with the property expressed by π. So  reinterpreted, the truth condition for   (23)  is: 