 The problem of definite-valued properties was approached in a more general way by Bub and Clifton (1996); for an improved version, see Bub, Clifton and Goldstein 2000). These authors started from the assumption that the definite-valued subset is determined by the dynamical state \(\ket{\phi}\) plus a “privileged observable” \(\boldsymbol{R}\), representing a property that is always definite-valued a priori. From this perspective, Bub (1992, 1994, 1997) drew the conclusion that with hindsight a number of traditional interpretations of quantum theory might be viewed as modal interpretations. Among them are (what Bub took to be) the Dirac-von Neumann interpretation and Bohr’s interpretation; and, as a more clear-cut case, Bohm’s theory. Indeed, this theory (Bohm 1952) is a modal non-collapse interpretation with position as the privileged observable \(\boldsymbol{R}\). A more recent proposal for a modal scheme using a privileged observable is the Modal-Hamiltonian interpretation (see Section 8).