Abstract This paper provides an explanation for aspects of the behaviour of the English modal auxiliaries based at the syntax–semantics interface. The core idea is a marriage of Kratzer's [Linguistics and Philosophy, 1 (1977), 337] classical analysis of modals as propositional operators with current minimalist ideas about the propositional nature of phases [Chomsky (1999) MITOPL, 18]. This gives rise to two scope positions for modals: one associated with the vP phase, and one with the CP phase. It is shown that the former scope position leads to root readings of modals and the latter to epistemic readings.