Modern Views of Medieval Logic ed. by Christoph Kann et al. (review)

An awareness of the wide scope of medieval logic and the role it played in university education at all levels, together with the way it was used in writings on both science and theology, is crucial for the historian of medieval thought. The growth of this awareness since the mid-twentieth century is shown by the ongoing expansion of editorial work, together with the discussion of the logic actually found in such prominent authors as Aquinas and Scotus. It has gone hand in hand with the use of developments in modern logic. First came the realization that medieval logic extended beyond basic Aristotelian syllogistic, and could be related to modern developments in propositional and quantificational logic in interesting ways. More recently, contemporary logicians have gone beyond stripped-down formal systems to a more complex modelling of other types of reasoning in developments such as temporal logic and epistemic logic. This collection of essays sets out to show not only that these developments can illuminate medieval logic itself, but also that modern logicians can learn from the insights displayed in medieval logic.

How the essays work out these aims is variable. Ebbesen's useful essay on how the modes of signification (modi significandi) were used in medieval grammar and logic leaves it to the reader to find modern applications, while the cluster of three lucid and thought-provoking essays by Read, Restall, and Zardini on truth and epistemic paradoxes as treated in the work on insolubilia by the fourteenth-century thinker Bradwardine (d. 1349) are more largely directed to the modern logician. A middle ground is occupied by the two essays on future contingency, namely, the theological problem of whether human beings can have genuine free will now if an omniscient God already knows the choices that they will make in the future. Øhrstrøm uses modern tempo-modal logic to illuminate the work of the fourteenth-century English logician Lavenham, while Dvorak uses modal logic to discuss the view of the much later Spanish Dominican Alvarez (d. 1635), but both essays can be enjoyed by those without much technical knowledge.

The problem of future contingency was originally posed by Aristotle, and two other essays also relate to Aristotelian logic. Without being too technical, Knuuttila uses modern logic to discuss how three medieval authors treated modal syllogisms, two (Kilwardby and Campsall) in their commentaries on Aristotle, and one (Buridan) in his work on consequences. In a more technical but very readable presentation, Normore and Parsons use Buridan again, along with the English author Billingham, in a detailed analysis of how these authors appealed to expository syllogisms, namely, those with singular terms, to provide a foundation for syllogistic reasoning.

The remaining essays, like those on modi significandi and insolubilia, are devoted to topics that represent medieval additions to Aristotelian logic. The essay by Uckelman, Maat, and Rybalko, discusses how an early text on Obligationes treated the role of doubting in disputations, while Amerini and Mugnai discuss a later author, Franciscus de Prato, on reduplicatives, that is, propositions using such connectives as 'insofar as.' However, the topic that is treated most fully is supposition theory, to which three essays, by Cesalli with Goubier, Dutilh Novaes, and Ward, are devoted. Cesalli and Goubier provide an interesting comparison of medieval theories to the semantic theories of Anton Marty (d. 1914), but the essay that I found most exciting was that by Dutilh Novaes on Ockham. Without being too technical, she lays out in detail her reasons for thinking that Ockham's theory of supposition can be viewed as a formal theory of propositional meaning while still using a version of ordinary language, rather than invented symbols.

While there is much of interest in this collection, which stems from a 2007 workshop, there are several ways in which it fails to be reader-friendly. It opens with summaries of each contribution...