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Doctoral dissertation project of Guido J. Alt

John Buridan’s Metaphysics of Modality: nominalism, logic and reality in the Quaestiones on the Metaphysics (working title)

My doctoral research investigates the metaphysics of modality of John Buridan [Iohannes Buridanus] (1295/1305–1358/61), the late medieval logician, secular philosopher and arts master teaching at the University of Paris during the second and third quarters of the 14th century. My aim is to examine the methodological application of his analysis of modal terms found in the logical works to metaphysical problems arising from Aristotle’s text in detail throughout the Quaestiones on the Metaphysics, where explanatory desiderata are also at the center of Buridan’s concerns.

John Buridan is regarded as a consolidator of the nominalist tradition in later medieval philosophy across Europe; as an illustration of the influence of his thought, the oldest statutes of the University of Cologne (from the end of the 14th century) prescribe the study of his logical magnum opus, the Summulae de Dialectica, as obligatory for the Faculties. Several manuscripts of his extant works are widely spread among European Universities. Although his commentary on the metaphysics has had a less impressive fortune than his logical works, or his ethics when it comes to numbers, it was highly influential and shaped together with his other works the way philosophy in the via moderni was supposed to look like for posteriority. But in contrast to his works on philosophical semantics and logic, Buridan’s quaestio-commentary on Aristotle’s Metaphysics is receiving historical and systematic attention by scholars only in recent years.

His approaches to language, which constitute attempts to fashion a purely nominalist semantics as the method for philosophical analysis, are often taken by scholars to speak directly to contemporary concerns. His modal logic is considered by many experts to be ahead of his time - modal logic being roughly the logic of the concepts of possibility and necessity, the analysis of which is often taken to yield metaphysical results about reality, so important are these concepts for our thoughts about the fundamental characteristics of the world and also very present in Aristotle’s original project on the Metaphysics.

The aim of my doctoral project is thus to examine the applications of this doctrine to the metaphysics of modality in the Quaestiones on Aristotle's Metaphysics. This involves (i) the approach to modal syncategorematic (that is, verbs such as ‘can’ and ‘must’) and to modal categorematic terms (that is, connotative terms supposing for activities and causal powers) in the context of this work; (ii) the location of the abstract pair act/potency in the predicables and metaphysical problems of priority of one over the other; (iii) the account of how modal distinctions such as the abstract pair act/potency (and its denominative concrete counterparts) are known and how do demonstrations and causal definitions of modal facts come about; (iv) the notion of 'causes of truth' in the discussion of propositions which do not stand for actually existent objects; (v) the modal status of past, present and future events.


Short biography

Guido J. Alt joined the Marie Skłodowska-Curie a.r.t.e.s. EUmanities Program and the Thomas-Institut in April 2018, under supervision of Prof. Dr. Andreas Speer. His research is being jointly supervised by Prof. Dr. Henrik Lagerlund at Stockholm University, where he will also work on his jointly supervised doctoral research project. Before that, he studied philosophy at the Pontifícia Universidade Católica do Rio Grande do Sul (Brazil) and the University of Tübingen, completing his B.A. in 2015. Subsequently he worked on a M.A. research on Duns Scotus’s metaphysics of identity and distinctions at the Pontifícia Universidade Católica (2017). The resulting thesis, supervised by Prof. Dr. Roberto Pich (Pontífica Universidade Católica) and examined by Prof. Dr. José Filipe P. da Silva (University of Helsinki) was nominated for a Brazilian national prize. For his research, he also held a DAAD visiting fellowship at the Albertus-Magnus-Institut in Bonn in 2017.



Syllogizing ad probabilem in Pseudo-Scotus, In: Intuitio v. 11, n. 1, 2018, 77-85.



“Alonso Briceño (1587-1668) on Future Conditionals”, 4 September 2018, FIDEM Congress, “Past and Future of Medieval Studies Today: 6th European Congress of Medieval Studies”, University of Basel.

“Mediaeval Scepticism as an Historiographical Category: a case of paradigm shift?”, Summer School “Understanding the Past Today: Methodology in the History of Philosophy”, 26-29 June 2017, University of Groningen.

“Percepção Ativa e species intelligibilis: Scotus e o modelo de causação parcial”, 3 October 2017, I Workshop Cognição e Conhecimento na Idade Média, Pontifícia Universidade Católica do Rio Grande do Sul.



2018, Marie Skłodowska-Curie a.r.t.e.s. EUmanities Fellowship.

2018, Nomination for Prize of Best Philosophy M.A. Dissertation defended in Brazil by the National Association of Graduate Programs (ANPOF).

2017, Research Award from the Latin American DAAD Centre in Porto Alegre for a Research Stay in Germany (Albertus-Magnus-Institut, Bonn).

2016, Scholarship of the Brazilian National Council for Research and Technology (CNPq) for M.A. research.


Cover photo: Manuscript picture of Buridan’s Quaestiones super octo Physicorum libros Aristotelis. A scribal colophon dates and localizes the manuscript to Paris, 1395 (credit and source: Text Manuscripts, Les Enluminures – Paris, New York, Chicago) // Portrait Photo: Patric Fouad