I develop a novel semantic theory for modals that has important consequences for contemporary work in epistemology, metaphysics and ethics. My theory replaces the dominant view about semantics--that our best theory of meaning should ascribe truth-conditions to modalized sentences--with a non-truth-conditional yet fully compositional semantics for modals. Its contributions to current debates in analytic philosophy include an explanation of the possibility of modal disagreement that avoids relativism, a solution to the paradoxes about conditional obligations (including the gentle murder paradox), and new impulses for a generalized solution to the Frege-Geach problem for noncognitivism. / text

This dissertation proposes a novel treatment of deontic modals such as permission, obligation and prohibition with special attention to applicability to legal language.