By Peter Adamson

When philosophical texts in ancient Greek are unearthed, it is big news. Much excitement greeted the newly discovered fragments of Empedocles, found in a library in Strasbourg (See A. Martin and O. Primavesi, L’Empédocle de Strasbourg [Berlin: 1999]). More recently leading scholars have devoted themselves to a previously unknown commentary on the Categories, found in a palimpsest manuscript also containing texts by Archimedes. Usually, previously unknown Arabic philosophical works cause less fuss. And in a way, rightly so. It is commonly thought that philosophy in the Islamic world declined or even died out following the work of Averroes in the twelfth century CE. But in fact there are hundreds of philosophical texts from later periods of Islamic history that survive today as manuscripts in Arabic, Persian and other languages. These works are mostly unstudied, so that in fact the vast majority of philosophical texts from this culture are as yet “undiscovered,” even if their existence is (sometimes) listed in library catalogues.

Still, we usually take ourselves to have a good sense of what survives from the earlier, “formative” period of philosophy in the Islamic world (roughly, the ninth to twelfth centuries). So in the circles I run in, at least, eyebrows were raised, and perhaps a jaw or two was dropped, when attention was drawn to an Iranian manuscript that contains numerous treatises by the tenth century thinker Yahya ibn Adi. To which you may say: who was Yahya ibn Adi? He’s not a household name now, but in his own day he had great renown as the foremost Aristotelian philosopher in the capital of the Islamic empire, Baghdad. This is a sign of the ecumenical nature of intellectual life in the period. Ibn Adi was a Christian, who studied with and taught other Christian philosophers, associated with the famous Muslim thinker al-Farabi, and engaged in an epistolary exchange on philosophical topics with a Jewish scholar. Which is not to say that philosophy entirely transcended religious divides. Ibn Adi rebutted a critique of the dogma of the Trinity, composed by the earlier Muslim philosopher al-Kindi, and used his philosophical knowledge to develop his own Trinitarian theory. Other Christian members of the group at Baghdad were capable of writing lengthy commentaries on both Aristotle and books of the Bible.

All this was well known before the Iranian manuscript came to light, thanks to earlier editions and research by scholars like Augustine Périer, Sahban Khalifat and Gerhard Endress. But the new manuscript fills out the picture considerably, by giving us access to otherwise lost works. This was announced by Rob Wisnovsky of McGill University, who got hold of images of the manuscript after seeing in a catalogue that it listed numerous treatises by Ibn Adi. Here is Rob’s account of the discovery:

“In 2010, with the help of an Iranian colleague, I acquired digital images of a philosophical codex from the library of the Madrasa-yi Marwi in Tehran. I was prompted to do so because the very brief entry in the Madrasa-yi Marwi manuscript catalogue claimed that this codex contained around 50 Yahya ibn ‘Adi treatises, among other works of classical Arabic philosophy. But at the time I didn’t think there was anything really special about the codex: the Yahya treatises were not listed by title in the catalogue entry, and there was no indication that any of them had in fact been thought to be lost…This is not unusual: Arabic-manuscript cataloguers have to collate huge numbers of manuscripts, many of them lengthy (i.e., 300+ folios) codices containing dozens of individual short treatises by various different authors. In suchcases the cataloguer often just gives a general description of the contents rather than a detailed list of authors and titles. When I received the digital images of the codex, I made a detailed list of the contents, and then collated my list of the Yahya treatises contained in the codex with the comprehensive inventory of Yahya’s works published by Gerhard Endress in 1977, as well as with the edition of Yahya’s philosophical treatises published by Khalifat in 1988. At that point I realized how precious the codex was: around two dozen of the Yahya treatises contained in the codex were considered not to be extant.”

Rob has since been producing studies of the manuscript’s contents, sometimes in collaboration with colleagues. He will soon publish a facsimile of the manuscript under the title A Safavid Anthology of Classical Arabic Philosophy. A list of the treatises can be found in the essay “New Philosophical Texts of Yaḥyā Ibn ʿAdī: a Supplement to Endress’ Analytical Inventory,” published in Islamic Philosophy, Science, Culture, and Religion: Studies in Honor of Dimitri Gutas. Among the articles he has produced offering editions, translations and analyses of individual treatises, two are co-authored with myself. The newly available treatises don’t radically overturn our ideas about Ibn Adi, but even at this fairly preliminary stage one can draw several morals from this story.

First, if you look at the previous secondary literature on Ibn Adi you’ll see that it is largely bifurcated into work on his Christian theology and work on his Aristotelian philosophy. But the two sides of his thought clearly interrelate. As just mentioned, he uses philosophical ideas to argue for a certain conception of the Trinity, and one of the new treatises contains a section that also appears verbatim in a Trinitarian work. As Wisnovsky and a co-author, Stephen Menn, comment: “in this case, the line dividing Yayha’s theological and philosophical works was quite blurry.” Second, there is Ibn Adi’s interest in Islamic theology. In a work of his that has been known for a long time, he takes up a theory of some Muslim theologians, to the effect that God “creates” our actions, but we bear moral responsibility nonetheless by “acquiring” those actions. Ibn Adi gives the theory short shrift, and one may easily come away with the expression that he had little interest in a deep engagement with Islamic religious thought. Yet in one of the newly discovered texts, he critiques another such argument, this one a standard proof of God’s existence. This suggests that he – and by extension, the group of Christian thinkers to which he belonged – had a more abiding and serious concern with Islamic theology.

In still other treatises, Ibn Adi shows that his reputation as a skilled Aristotelian exegete is well earned. He comments on standard problems in logic, for instance whether Aristotle was correct in setting the number of categories at ten; and on individual passages of Aristotle, in one case sorting out Aristotle’s perplexing claim that god is located “in” the outermost sphere of the universe. As these treatises are made available, translated and studied, we will have an improved picture of the Arabic reception of Aristotle. But the picture already shows that, thanks to Ibn Adi and his colleagues, tenth century Baghdad rivalled fifth century Alexandria, thirteenth century Paris, and twentieth century Oxford when it comes to Aristotelian scholarship.

Peter Adamson is a professor of philosophy at the Ludwig-Maximilians-Universität in Munich. He is the author of the History of Philosophy podcast, which is appearing with Oxford University Press in the form of a series of books, entitled A History of Philosophy Without Any Gaps.