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Reassessing Ninth Century Philosophy. A Synchronic Approach to the Logical Traditions

Periodic Reporting for period 3 - 9 SALT (Reassessing Ninth Century Philosophy. A Synchronic Approach to the Logical Traditions)

Reporting period: 2018-09-01 to 2020-02-29

This project aims at a better understanding of the philosophical richness of ninth century thought using the unprecedented method of a synchronic approach. The hypothesis guiding this synchronic approach is that studying together in parallel the four main philosophical traditions of the century - i.e. Latin, Greek, Syriac and Arabic - will bring results that the traditional enquiries limited to one tradition alone can never reach. The ninth century, a time of cultural renewal in the Carolingian, Byzantine and Abbasid empires, possesses the remarkable characteristic that the same texts, namely the writings of Aristotelian logic (including also Porphyry's Isagoge) were read and commented upon in Latin, Greek, Syriac and Arabic alike.
The project studies, in a precise historical context, fundamental questions related to the human capacity to rationalise, analyse and describe sensible reality, to understand the ontological structure of the world, and to define the types of entities which exist. It provides a unique opportunity to compare different traditions and highlight their common Aristotelian heritage, to stress the specificities of each tradition when tackling philosophical issues and to discover the doctrinal results triggered by their mutual interactions, be they constructive (scholarly exchanges) or polemic (religious controversies).
Logic is fundamental to philosophical enquiry, but it is also a fantastic tool to be used outside a strictly philosophical context. Logic is an extremely useful way to strengthen one’s own position, by establishing conclusions through rational deductions and by proposing syllogistic reasoning, but also to undermine the position of an adversary in an intellectual or religious controversy, by showing that his opinion implies contradictions or absurd consequences. Studying occurrences of such uses of logical tools is a precious mean for the historian to assess the place of rationality in public discourses.
The first part of the project has been devoted to the careful reading and analysis of the logical texts written during the ninth century, to a study of the logical manuscripts copied during the long ninth century (including the study of glosses when the manuscripts were glossed), and to an analysis of ninth century texts using Aristotelian logic, but whose primary concern is not philosophical. This has been completed by a thorough reflexion about methodology.

Three international conferences have been organised in Vienna, with plenary papers by the PI, the members of the research team and the affiliated scholars. These conferences are:
- “Theodore the Stoudite. Intellectual Context, Logic, and Theological Significance” (University of Vienna, 9-11 March 2016)
- “Understanding Individuality and Depicting Individuals in Ninth Century Byzantium” (University of Vienna, 1-3 March 2017)
- “Arguing Against. Logical Reasoning and Arguments in Religious Controversies (8th -10th Centuries)”, (University of Vienna, 28 February - 2 March 2018),

The PI, Christophe Erismann, (PI) has written several articles presenting aspects of his research for the project, including:
“Meletius Monachus on individuality: a ninth-century Byzantine medical reading of Porphyry's Logic”, Byzantinische Zeitschrift 110.1 (2017) 37-60.
“Theodore the Studite and Photius on the Humanity of Christ. A neglected Byzantine Discussion on Universals in the Time of Iconoclasm”, in: Dumbarton Oaks Papers 71 (2017) 175-192.
“Venerating Likeness: Byzantine Iconophile Thinkers on Aristotelian Relatives and their Simultaneity”, British Journal for the History of Philosophy 24/3 (2016) 405-425.
“Logic in Byzantium”, in A. Kaldellis, N. Siniossoglou (eds), in: The Cambridge Intellectual History of Byzantium. Cambridge, CUP, 2017, 362-380.
“Theological Dispute, Logical Arguments: On Photios´ use of syllogisms against the Filioque in the Mystagogia”, in A. Bucossi et A. Calia (eds), Contra Latinos et Adversus Graecos: The separation between Rome and Constantinople from the 9th to the 15th century. Louvain, Peeters, in press.
“Ontologie et logique à Byzance. Photius Ier de Constantinople et la distinction entre les termes ‘homme’ et ‘humanité’ ”, Les Études Philosophiques, 2018, in press.
“Nicephorus I of Constantinople, Aristotelian Logic and the Cross”, in: M. Knežević (ed.), Aristotle in Byzantium. Sebastian Press, 2018, in press.
“On the Significance of the Manuscript Parisinus graecus 437. The Corpus Dionysiacum, Iconoclasm, and Byzantine-Carolingian Relations”, in F. Daim, C. Gastgeber, D. Heher, C. Rapp, (eds), Menschen, Bilder, Sprache, Dinge. Wege der Kommunikation zwischen Byzanz und dem Westen. Verlag des Römisch-Germanischen Zentralmuseums, Mainz, 2018, forthcoming.
“Between Greek and Latin: Eriugena on logic, in: A. Guiu, S. Lahey (eds), The Brill Companion to Eriugena, 2017, in press.

For the period covered by this report, the PI has given twenty talks, the great majority of them on invitation, presenting aspects of his research for the ERC project, including:
“Quelques lecteurs byzantins de l'Isagoge de Porphyre: Théodore de Raithu, Mélétius, Photius, Aréthas de Césarée” conference L'Isagoge di Porfirio e la sua ricezione tardoantica e medieval (Padua, 8-10 November 2017)
“The Middle Byzantine Reception of the Alexandrian Logical Commentaries: a Study of the Afterlife of Ammonius', Olympiodorus' and Elias' Commentaries on the Categories”, Conference Aristoteles-Kommentare und ihre Überlieferung in Spätantike, Mittelalter und Renaissance (Hamburg, 26-28 October 2017)
“Relational homonymy. On some opinionated Byzantine readings of Categories 1a1-6”, Conference Philosophy in Byzantium: The Order of Nature and Order of Humankind (Munich, 4-6 October 2017)
“Aristote chez le Patriarche. Photios Ier de Constantinople et les Catégories” Conference Catégories de langue, caté
Several results are expected. They are of three kinds.

1. A new narrative of the history of logic during the ninth century. The traditional description includes only the analysis of the exegetical work done during the ninth century on Aristotelian logical texts. 9SALT takes into consideration a lot more material, by including in its study writings which are not primarily philosophical but in which logic is abundantly used. The consideration of this material allows a more detailed and precise picture, and a better evaluation of the role of logic, the level of scholarship and the logical culture of the main thinkers of the century. This aim will be fulfilled through research articles and a monograph by the PI.

2. The use of the unprecedented synchronic approach will allow a deeper understanding of the positions held at the time, a clear identification of the a priori postulates (proper to each tradition) of the philosophical debates, and a critical evaluation of the arguments used. This will be done through a comparison of the way in which philosophical problems are answered in the different traditions.

3. The making accessible of texts previously untranslated texts in English (or in other modern languages) in some cases, together with an edition of the text in original language. This will notably be done thanks to the publication of an anthology of logical texts in translation.