Normative logic in the late Middle Ages: an analysis of deontic modalities in Rogerius Rosetus's Lectura super Sententias

Abstract

This article investigates the emergence of deontic modalities in late medieval logic through an analysis of Rogerius Rosetus's Lectura super Sententias. Situating Rosetus within the broader context of fourteenth-century modal logic, the study examines how deontic operators such as obligation, permission, and prohibition were incorporated into scholastic discussions of modality. Particular attention is given to the distinction between de re and de dicto modal propositions, the analogical relationship between alethic and deontic modalities, and the theological questions that motivated these developments. By comparing Rosetus's approach with those of thinkers such as Peter Abelard, William of Ockham, Robert Holcot, and Gregory of Rimini, the article argues that late medieval logicians developed sophisticated logical tools for analyzing normative discourse, anticipating important themes of modern deontic logic.