The first book-length study to address issues in modal logic at the eve of the Renaissance, this monograph provides important new insights into the way the debates on modal logic during the post-medieval period tied in with the so-called Wegestreit, the divide between the via antiqua and via moderna that dominated the discourse on logic during the 15th and early 16th centuries. The focus of the book is on the logic and philosophy of language of John Fabri of Valenciennes (fl. c. 1500), one of the last exponents of the terminist approach to logic that was bitterly criticized by the humanist movement. By means of a careful reconstruction of Fabri’s text, the book argues that Fabri's modal logic ultimately goes back to the work of John Buridan, and represents the same approach to the topic as the modal logics that were developed by adherents of the via moderna in Paris. This has significant implications for the historiography of post-medieval philosophy. Fabri was active in Louvain, which until the late 16th century was the most important intellectual center in the Low Countries. According to a long-standing tradition in the scholarship, Louvain was one of the few bulwarks of via antiqua logic on the map of post-medieval Europe. The book argues that this thesis is at least in part a scholarly fiction, and thus in need of revision. By shedding light on an author whose thought has thus far remained entirely unstudied, it also constitutes a valuable step towards a history of philosophy without any gaps. The book is aimed at graduate students and researchers in the history of logic and philosophy, but will also be of interest to intellectual historians, historians of ideas, and to any contemporary modal logician who is interested in the historical roots of their discipline.

In Political Theology the "Modern Way": The Case of Jacques Almain (d. 1515), Shaun Retallick provides the first monograph on this late medieval philosopher-theologian and conciliarist, and his thought. He demonstrates that Almain's political theology, of which ecclesiology is a sub-discipline, is strongly impacted by the Via moderna. At the heart of his political theology is the individual and his or her will. Yet, the individual is rarely viewed in isolation from others; there is a strong emphasis on community and on the religious and secular bodies through which it is realized. But these bodies, including the Church, are understood in collectivist rather than corporatist terms, which tends to a quite radical form of conciliarism.

This book explores noteworthy approaches to modal syllogistic adopted by medieval logicians including Abélard, Albert the Great, Avicenna, Averröes, Jean Buridan, Richard Campsall, Robert Kilwardby, and William of Ockham. The book situates these approaches in relation to Aristotle's discussion in the Prior and Posterior Analytics, and other parts of the Organon, but also in relation to the thought of Alexander of Aphrodisias and Boethius on the one hand, and to modern interpretations of the modal syllogistic on the other. Problems explored include: Aristotle's doctrine of modal conversion, the pure and mixed necessity-moods, modal ecthesis, the pure and mixed contingency-moods, and Aristotle's use of counter-examples. Medieval logicians brought various concepts to bear on these problems, including the distinction between per se and per accidens terms, the notion of essential predication, the distinction between ut nunc and simpliciter propositions, the distinction between de dicto and de re modals, and the notion of ampliation. All these are examined in this book.

In this text, a variety of modal logics at the sentential, first-order, and second-order levels are developed with clarity, precision and philosophical insight. All of the S1-S5 modal logics of Lewis and Langford, among others, are constructed. A matrix, or many-valued semantics, for sentential modal logic is formalized, and an important result that no finite matrix can characterize any of the standard modal logics is proven. Exercises, some of which show independence results, help to develop logical skills. A separate sentential modal logic of logical necessity in logical atomism is also constructed and shown to be complete and decidable. On the first-order level of the logic of logical necessity, the modal thesis of anti-essentialism is valid and every de re sentence is provably equivalent to a de dicto sentence. An elegant extension of the standard sentential modal logics into several first-order modal logics is developed. Both a first-order modal logic for possibilism containing actualism as a proper part as well as a separate modal logic for actualism alone are constructed for a variety of modal systems. Exercises on this level show the connections between modal laws and quantifier logic regarding generalization into, or out of, modal contexts and the conditions required for the necessity of identity and non-identity. Two types of second-order modal logics, one possibilist and the other actualist, are developed based on a distinction between existence-entailing concepts and concepts in general. The result is a deeper second-order analysis of possibilism and actualism as ontological frameworks. Exercises regarding second-order predicate quantifiers clarify the distinction between existence-entailing concepts and concepts in general. Modal Logic is ideally suited as a core text for graduate and undergraduate courses in modal logic, and as supplementary reading in courses on mathematical logic, formal ontology, and artificial intelligence.

Advances in Modal Logic is a unique forum for presenting the latest results and new directions of research in modal logic. The topics dealt with are of interdisciplinary interest and range from mathematical, computational, and philosophical problems to applications in knowledge representation and formal linguistics.Volume 3 presents substantial advances in the relational model theory and the algorithmic treatment of modal logics. It contains invited and contributed papers from the third conference on OC Advances in Modal LogicOCO, held at the University of Leipzig (Germany) in October 2000. It includes papers on dynamic logic, description logic, hybrid logic, epistemic logic, combinations of modal logics, tense logic, action logic, provability logic, and modal predicate logic."