Medieval logic is usually divided into the branches that derived from Aristotle's organon - the 'logica vetus' and 'logica nova', and those invented in the Middle Ages, the 'logica modernorum'. In this volume, a group of distinguished specialists asks whether the ancient roots of medieval logic were not in fact more varied. Stoic logic was mostly lost, but were some of its themes transmitted, even in distorted form, through Boethius and through the grammatical tradition? And did other schools, such as the sceptics and the Platonists, contribute in their own ways to medieval logic?

This volume, the first dedicated and comprehensive companion to medieval logic, covers both the Latin and the Arabic traditions, and shows that they were in fact sister traditions, which both arose against the background of a Hellenistic heritage and which influenced one another over the centuries. A series of chapters by both established and younger scholars covers the whole period including early and late developments, and offers new insights into this extremely rich period in the history of logic. The volume is divided into two parts, 'Periods and Traditions' and 'Themes', allowing readers to engage with the subject from both historical and more systematic perspectives. It will be a must-read for students and scholars of medieval philosophy, the history of logic, and the history of ideas.

This book presents formalizations of three important medieval logical theories: supposition, consequence and obligations. These are based on innovative vantage points: supposition theories as algorithmic hermeneutics, theories of consequence analyzed with tools borrowed from model-theory and two-dimensional semantics, and obligations as logical games. The analysis of medieval logic is relevant for the modern philosopher and logician. This is the first book to render medieval logical theories accessible to the modern philosopher.