Some modals are ambiguous between epistemic and circumstantial interpretations, but allow epistemic readings only when they combine with stative verb phrases. For other modals, the epistemic reading is not so constrained. I propose a theory of modal semantics that is sensitive to height of merge position and by extension the properties of the situational description that the modal combines with. To capture the pattern, modals are argued to have two important dimensions of meaning: (i) they will describe a topic situation asserted to be either an exhaustive or non-exhaustive choice over live situational alternatives; (ii) they will either anchor that topic situation indexically, or anaphorically. Modal meaning can then systematically interac...