The Heirs of Avicenna: Philosophy in the Islamic East, 12-13th Centuries

Front matter

ISLAMICATE INTELLECTUAL HISTORY 12/1

The Heirs of Avicenna: Philosophy in the Islamic East, 12-13th Centuries

Metaphysics and Theology

Contents

Acknowledgements VII

The Subject Matter of Metaphysics and Kalam The Essence-Existence Distinction 64 Univocity and Equivocity of Existence 109 Non-Existence and Mental Existence 138 Universals 189

Bibliography 701 Index Locorum 719

Introduction

This book is the first in a series of volumes devoted to the reception of the thought of Abu ‘Ali Ibn Sina (d. 428 AH, 1037 CE), usually known in English by his Latin name Avicenna, in the Islamic East during the 12-13th centuries CE. He was the central figure for thinkers of this time and place. Some engaged in summarizing, interpreting, and defending his teachings, while others attacked those same teachings. Quite a few did both. But no philosophically-minded author could ignore him. As a result, the task of documenting his reception is pretty close to charting the whole development of philosophy during the period. Our hope is that the book series will provide a resource for further work on this chapter in Islamic intellectual history, and cement the growing sense among scholars that this was a time of great philosophical achievement.

The corpus of writings produced in this period may usefully be compared to the “high scholastic” era in Latin Christendom. We are dealing with an enormous amount of material by authors of varying intellectual approach, who produced intricate and often technical arguments, presupposing familiarity with specialist vocabulary and with debates that ran across the generations. The main difference is that in the Islamic East these debates revolved around Avicenna, whereas in the later scholastic tradition it was of course Aristotle who set the terms of discussion. On the other hand, Avicenna was powerfully influential on the Latin tradition too, and on philosophy in the Western Islamic world or maghreb, which we have not attempted to include here. Indeed, when we combine the Latin reception, the Western Islamic reception, and the reception in the Islamic East which is (only partially) displayed in this book series, we can only conclude that Avicenna was by some distance the most seminal thinker of the medieval period in the parts of the world dominated by the Abrahamic religions.

One feature common to Latin scholastic philosophy and philosophy in the Islamic East is that it was often practiced within a theological context. In Latin Christendom this was very explicitly the case, as major philosophers were members of theology faculties at universities and even put the word “theology” in the titles of their works (Aquinas would be a famous example of both). In the Islamic world authors were not formally designated as “theologians” in this way, but it is clear that many or even most of the thinkers quoted within these pages were adherents of one or another theological tradition, such as Ash'arite kalam or a given branch of Shi‘ism. In a controversial recent paper a leading scholar of the field, Dimitri Gutas, revised his earlier assessment of

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post-Avicennan thought as a “golden age” of philosophy, to propose that we are actually dealing with something he calls “paraphilosophy.”! His point is that such apparently “philosophical” argumentation as we find in our period is compromised by the wider motives of the authors. For Gutas, philosophy in the strict sense should be an “open-ended and rational inquiry into reality.’ The post-Avicennan authors, by contrast, were constrained by religious or other doctrines which they assume to be true in advance, so that their inquiry was not really “open-ended.” Their work constitutes “paraphilosophy” because they are “doing what appears to be philosophy/science in order to divert attention from, subvert, and substitute for philosophy/science, and asa result avoid doing philosophy/science.”

There is a lot that could be said in response to this, beginning with the observation that by this standard, such figures of the aforementioned scholastic tradition as Aquinas, Scotus, and Ockham would not be philosophers either, leaving us with a vision of “medieval philosophy” in Latin Christendom that would at best include only a few arts masters like Siger of Brabant and John Buridan. (This seemingly conversation-ending bullet is one Gutas is ready to bite, though.) Also, as will be clear even from the brief historical overview presented later in this introduction, the thinkers of our period were approaching Avicenna, and philosophy, from a very diverse range of perspectives. It would clearly be painting with too broad a brush to say that all the figures quoted in this volume were “paraphilosophers,” even by Gutas’ criteria. Indeed, a single author may seem to be a philosopher in one book, and a paraphilosopher in another book. We will have more to say about this problem below. But this introduction is not the place to engage fully with Gutas' article,” if only because it is hard to imagine any response more thorough or convincing than the rest of the book and its sequels. If you can read what follows here and convince yourself that it is not philosophy, then we would be very surprised. At the very least, it will be clear that there is plenty of sophisticated argumentation going on in the Islamic East in the centuries after Avicenna, argumentation that should be of great interest to historians of philosophy. That seems a sufficient rationale for our undertaking.

1 D.Gutas, “The Heritage of Avicenna: The Golden Age of Arabic Philosophy, 1000—ca. 1350,’ in J. Janssens and D. De Smet (eds), Avicenna and his Heritage (Leuven: 2002), 81-97; D. Gutas, “Avicenna and After: The Development of Paraphilosophy. A History of Science Approach,” in A. Al Ghouz (ed.), Islamic Philosophy from the 12th to the 14th Century (Gottingen: Bonn University Press, 2018), 19—72.

2 For one detailed response see J. Kaukua, “Post-Classical Islamic Philosophy: a Contradiction in Terms?” al-Nazariyat 6 (2020), 1-21.

Accordingly, this book series is aimed primarily at a philosophical readership. Our goal is to give readers access to philosophical conversations that took their starting point from Avicenna’s writings and ran over the next several centuries. Actually they ran still further than that. One could extend this project to look at authors of the mid- or later-14th century like ‘Adud al-Din al-Iji (d. 1355) or Sa‘d al-Din al-Taftazani (d. 1390), or even further, pursuing the same themes we cover here into the school of Shiraz or the period of the Ottoman, Safavid, and Mughal empires. We have limited ourselves to a more practicable period of two centuries, roughly from the death of al-Ghazali in 1111 to the time of Nasir al-Din al-Tüsi (d. 1274) and his students. The resulting cast of characters is large, and we make an attempt later in this introduction to provide readers with an overview that situates them historically. But it must be admitted that the issue that was of most concern to Gutas—the overall intellectual projects of the various authors covered here—is not foregrounded by our own approach. Nor will readers of these books learn much about the wider historical context in which these thinkers were working.

Instead, taking inspiration from sourcebooks on periods in ancient philosophy? we have arranged our material thematically, enabling the user to pursue a topic like mental existence, modality in logic, or the powers of the soul, from Avicenna forward to the turn of the 14th century. To get a picture of the philosophy of a single figure, one could of course read across the chapters to see what that figure has to say on a range of themes. This would be particularly worthwhile when it comes to authors who adopted especially distinctive and innovative positions, and who play a significant role in almost every chapter, like al-Suhrawardi, Abu al-Barakat al-Baghdadi, Fakhr al-Din al-Razi, and al- Tūsī. But even in these cases, our volumes are no substitute for monographs giving a synoptic portrait of individual thinkers, such as are now increasingly available in English.*

3 Namely A.A. Long and D.N. Sedley, The Hellenistic Philosophers, 2 vols (Cambridge: 1987); R. Sorabji, The Philosophy of the Commentators, 200-600 AD: a Sourcebook, 3 vols (London: 2004).

4 For instance J. Kaukua, Suhrawardīs Illuminationism: a Philosophical Study (Leiden: 2022), L. Hassan, Ash‘arism Encounters Avicennism: Sayf al-Din al-Amidi on Creation (Piscataway, NJ: Gorgias Press, 2020), A. Shihadeh, Doubts on Avicenna: A Study and Edition of Sharaf al-Din al-Mas'üdi's Commentary on the Isharat (Leiden: Brill, 2016), and F. Griffel, The Formation of Post-Classical Philosophy in Islam (Oxford: 2021), which is useful for the whole period but especially focuses on Fakhr al-Din. One should not neglect older studies on individual thinkers, e.g. S. Pines, Studies in Abu'l-Barakat al-Baghdādī: Physics and Metaphysics (Jerusalem: 1979), and studies in Arabic and non-European languages e.g. M.S. al-Zarkan, Fakhr al-Din al-Razi wa-ar@uhi al-kalāmiyya wa-al-falsafiyya (Cairo: 1963).

4 INTRODUCTION 1 Method

That brings us to the question of how we went about producing this book. It offers translations of excerpts from at least half a hundred texts written over two centuries of philosophy. Given the enormous textual base, the selection of passages involved an uneasy marriage between comprehensiveness and feasibility. While we have attempted to provide a relatively complete picture of each theme in our time period, we would absolutely not claim to have provided an exhaustive account of the development of philosophy in the relevant period. This would be simply impossible, given our limited time and resources, and the current state of research. For one thing, we have not usually attempted to indicate which authors repeat the arguments and ideas of others. This was an accretive tradition, by which we mean that material from earlier authors is often taken up and reproduced by later ones, with or without citation of the source. For the most part we have contented ourselves with giving readers the earliest, clearest, or most frequently quoted version of a given argument or position, without citing the (often numerous) passages where the same material reappears. Occasionally we do give such references in notes, but the reader should be warned that the sheer size of our corpus means that no such list can be considered to be complete. On the other hand, where an author has an important signature doctrine (e.g. Fakhr al-Din on the univocity of existence) we usually quote several passages to give a full picture of this element of his thought.

One corollary of this strategy is that thinkers appear more frequently if they are more apt to innovate, or offer formulations or points that became a touchstone for subsequent authors. Authors like, say, Abū al-‘Abbas al-Lawkarī, a student of Avicenna who was usually happy simply to quote or paraphrase the master, are thus quoted only rarely. By contrast another student of Avicenna named Bahmanyar, who will emerge in this book series as far more important than usually assumed, is quoted fairly often. Of course neither of them fall within our official timespan, but we have included material from authors between Avicenna and al-Ghazali—including al-Ghazali himself—insofar as this seemed helpful for understanding the debate in our period proper. We do the same with pre-Avicennan authors to contextualize Avicenna, even to the extent of quoting key texts from Aristotle and other Greek philosophers. Still, we have kept this to a bare minimum, so that our choice of texts from before the 12th century is even more selective. In some cases we have saved time by quoting doxographical passages, as where an author like Ibn al-Malahimi or al- Shahrastani does us the favor of summing up the previous kalam discussion on a given topic. Of course these doxographies are to be approached with caution in terms of their accuracy and comprehensiveness, but they at least show how the state of play was seen in our period.

As with any sourcebook, this one could be accused of presenting material out of context. Indeed, a proponent of Gutas’ “paraphilosophy” thesis would probably say that while this book sure does make it look like there were thousands of pages of top-notch philosophy being written in our period, this is an illusion created by the lack of framing, as can be found for instance in the programmatic statements offered at the beginnings of works. To this our response would be, first, that this series is intended to complement other scholarship that does engage holistically with the corpora of individual authors. And second, that we are offering a different kind of context, which is usually more important for understanding the point of a given passage, by situating it within a chapter full of texts on the same issue. To understand, say, Ibn Kammüna's views on the problem of universals, it is certainly not irrelevant to know about Ibn Kammūnas whole enterprise as a systematic thinker. But it is absolutely crucial to know what people had been saying about universals up to his time. It is this sort of framing that our sourcebook does provide.

In terms of our translation style, we have striven to offer as readable as possible an English version of the passages, though it must be conceded that our authors do not make this an easy task. As already noted we are dealing for the most part with highly technical and intricate argumentation, driven forward by subtle distinctions and arguments with sub-arguments and sub-sub-arguments. Often, in a borrowing from kalam argument technique, we are given a range of options, with all but one eliminated to leave the right answer standing.? Again, the parallel to scholastic Latin philosophy suggests itself. Another difficulty is the abundance of technical terminology. We have not been overly concerned to translate the same word always in the same way, since we believe that this would often distort the meaning. To take two notorious cases, dhāt is sometimes "object," sometimes “essence,” sometimes "self"; the notorious word na manā appears as “meaning,” "entity," and even “something.” In many cases we provide transliterated Arabic in round brackets to help reader keep track of important terms, to see where the same term is being translated in different ways, and so on.

Another challenge, maybe the biggest challenge we faced apart from the sheer quantity of material, was the variable extent to which that material has

5 Anold but still very helpful study of the argumentative technique in kalām is J. van Ess, “The Logical Structure of Islamic Theology,’ in: G.E. Grunebaum (ed.), Logic in Classical Islamic Culture, Giorgio Levi Della Vida Biennial Conference, University of California (Wiesbaden: 1970), 21-50.

been edited. Hardly any text from our period exists in a critical edition that would live up to the standards applied by, say, editors of classical Greek literature. Usually the best one can hope for is a printed edition based on one manuscript, which mentions variants from other manuscripts in the notes. In many cases there is no edition, so we translate from a manuscript, where possible while consulting other manuscripts of the same text. But with the many dozens of works involved, obviously it would have been folly to pretend that we could get an adequate philological picture of the treatises from which we were translating. Far from having worked out a stemma codicum for each work, we are usually just citing from whichever manuscript(s) we could get access to. It is important to bear this in mind, since it means that every passage translated here is in some sense provisional. Proper philological investigation and an improved edition could change any of them and no doubt would change many of them. Thus, alongside deeper thematic studies building on what we offer here and comprehensive investigation of individual thinkers, there remains much to do on the philological front.

Finally on the question of method, it should be explained how we worked as a team. Thanks to the support of the DFG, which funded our work on this and the subsequent volumes, we were able to employ several postdoctoral researchers at Munich. For this volume the researcher was Fedor Benevich, who is now a lecturer at Edinburgh. Our procedure was that Benevich would work through the corpus of texts, select passages for translation, and produce draft English versions. These were then revised by Adamson, who also wrote the first draft of the thematic introduction to each chapter, which was in turn revised by Benevich. This twofold structure within each chapter should allow users to access the material at different levels. Probably every reader should start with the thematic introduction to get a general sense of the debate on each topic. The passages are arranged in rough chronological order, so one can then read the chapter straight through to see how things developed from Avicenna onward, or taking guidance from the thematic introduction, go straight to individual arguments or authors of particular interest. We also hope that the books can be used in teaching, and have already had some experience using draft chapters for this purpose. On this basis, our recommendation would be for instructors to make a selection of passages from a given chapter, and have the students read just the thematic introduction and the selected passages. This is because of the size of the chapters, and the density of the material, which rewards close reading. By contrast researchers are of course encouraged to look through all the material, ideally alongside the original Arabic, and to bear in mind that there is going to be further material of relevance that was not included, for the reasons already mentioned. It should also be borne in mind that a given passage may be relevant to more than one of our themes.® To save space we have not duplicated passages by including them in more than one chapter, but we do sometimes give cross-references to other chapters, and would encourage the reader to bear in mind that each chapter will typically be complemented by others. The introductions to each chapter will hopefully make the links between them clear.

2 Historical Overview

The quotations that make up the chapters are drawn from more than forty post-Avicennan philosophers who lived in the Islamic East between the late eleventh and early thirteenth century CE.’ The “Islamic East” takes in the heartlands of the Muslim world at the time, stretching roughly from Syria in the West to modern-day Afghanistan in the East. Vast though this territory is, it does exclude the maghreb. This means that we will in these books not be covering Ibn Rushd (Averroes, d. 198) and other thinkers who worked in Andalusia, or for that matter figures who worked in Cairo, such as the great Jewish thinker Maimonides. Certainly Avicenna was influential in this region as well, as already noted above, but it forms a separate tradition to some extent, and it would have been unfeasible to include these philosophers in our coverage. With regard to the thinkers we are covering, itshould be borne in mind that they often travelled widely in the Eastern Islamic realms. Let's take two prominent examples, al-Suhrawardi and Fakhr al-Din al-Razi. As his name indicates, the former was born in the Persian city of Suhraward. In between he journeyed first to Maragha, later a renowned centre of scientific and philosophical activity in the time of al-Tūsī, and already in al-Suhrawardi’s day a place where he could be initiated into philosophy by his master Majd al-Din al-Jīlī. He then

6 Moreover, some passages may be relevant for different volumes. For instance, the questions of modality and essentiality, understood nowadays as metaphysical issues, may be expected to be found in this volume. However, the reader will find the relevant chapters in the volume on Logic and Epistemology, since the authors of our period saw those issues as part of logic.

7 This section only attempts to provide a general historical overview of these authors to facilitate the use of the materials in the subsequent chapters. The reader can find detailed biobibliographical accounts of those authors in a few core publications focusing on the life and works of post-Avicennan philosophers: F. Griffel, The Formation of Post-Classical Philosophy in Islam (Oxford: 2021); Kh. El-Rouayheb, The Development of Arabic Logic (1200-1800) (Basel: 2019); A.H. al-Rahim, The Creation of Philosophical Tradition (Wiesbaden: 2018); U. Rudolph (ed.), Philosophie in der islamischen Welt: n. und 12. Jahrhundert: Zentrale und östliche Gebiete (Basel: 2021). This section largely relies on the accounts from these sources.

travelled to Anatolia, before winding up in Damascus and Aleppo where he was executed on the orders of Saladin. As for Fakhr al-Din, his name too connotes his place of birth: al-Razi means that he came from the Persian city of Rayy. His own travels took him to Nishapur and then Maragha, where he likewise studied with al-Jili. Where al-Suhrawardi went West, Fakhr al-Din ventured east, moving around central Asia as he became a client of rival political dynasties, the Khwarazm-Shahs and the Ghurids. A work called Debates (Munazarat) records his argumentative encounters with scholars in Transoxania. He finally died in Herat after rejoining the Khwarazm-Shahs. As even this sketch shows, student-teacher relationships and patronage were key factors in the careers of our authors, as they had been for Avicenna himself.

So much for the geography; now let us turn to chronology. The history of metaphysics and theology in the Islamic East in this period can be divided into three phases, which we describe as periods of formation, culmination, and refinement. But we begin earlier than that, with a look at the background to Avicenna himself.

3 Prehistory

In the middle of the eleventh century, the two predominant philosophical traditions in the Islamic world were falsafa and kalam. Falsafa was the philosophical tradition that takes its origins from ancient and late-Ancient Greek philosophy, primarily Aristotle and Neoplatonism. It began in the ninth century CE as a by-product of the Graeco-Arabic translation movement. The most important early falsafa-philosophers were Abū Ya‘qub ibn Ishaq al-Kindi (d. 873), Abū Bakr al-Razi (d. 925), Yahya ibn ‘Adi (d. 974), and Abu Nasr al-Farabi (d. 950). Although all these authors were known in the post-Avicennan tradition, the philosophers of this later period were unanimously agreed that the philosophical tradition of falsafa culminated with the unique synthesis of Aristotelianism, Neoplatonism, and original thought in the works of Avicenna. Thus the reader will find only sporadically the names of other falsafa-philosophers in the pages of this book.

We consider kalam as another philosophical tradition of the Islamic world, but one very different from falsafa in its nature and history. Unlike falsafa, kalam barely has any historical relation to ancient and late ancient Greek philosophy. Its origins and early development are rather obscure due to the lack of sources, but it is certain that by the beginning of the eleventh century, kalam had developed into a fully formed philosophical tradition with its own methods, terminology, and standard issues such as proofs for the existence of God, free will and the conditions of moral responsibility, and the composition of physical objects. The two predominant traditions of kalam relevant for post- Avicennan philosophical discourse are the Mu'tazilism and Ash'arism.

The Muttazilites who are mentioned in post-Avicennan sources can be roughly divided into two periods: classical and *reformed" Mu'tazilism. The most influential classical Mu'tazilite authors, the members of two competing schools of Basra and Baghdad, were Abū ‘Ali al-Jubbāī (d. 915/6), his son Abū Hashim al- Jubba' (d. 933), Abū al-Qasim al-Balkhi al-Ka'bi (d. 931), Abū ‘Abdallah al-Basrī (d. 980), and ‘Abd al-Jabbar (d. 1024). Post-Avicennan sources seem to agree that the important turn in the Mu'tazilism came in the eleventh century with Abu al-Husayn al-Basri (d. 1044). Abu al-Husayn is credited with philosophical views that would differ from the traditional Mu'tazilite approaches, on such questions as the nature of non-existence, the theory of states (ahwal), God's knowledge, and theory of action. Traditionally opposed to Mu'tazilism were the Ash'arites, that is, the followers of Abü al-Hasan al- Ash'ari (d. 936). The most prominent representatives of the classical Ash‘arism were Abū Bakr al-Bāgillānī (d. 1013), Abū Ishaq al-Isfara'ini (d. 1027), Abū al- Ma'alial-Juwayni (d.1085), and Abt al-Qasim al-Ansari (d. 1118). Ash'arism plays crucial role in the formation of post-Avicennan philosophy, with a few philosophers describing themselves as the proponents of this school of kalam.

4 Formation

The opposition between falsafa and kalam defines the character of philosophy in the formative period of post-Avicennan philosophy in the Islamic East.? The authors who write in this period can be divided into those who are mostly faithful to falsafa, that is, to the teachings of Avicenna, and those who adhere to the positions of kalam and attack Avicennan philosophy on this basis.

The philosophers who most appropriately may be called Avicennans are the representatives of Avicenna's own school. The first and most influential among them is Bahmanyar ibn al-Marzuban (d. 1044), a direct student of

8 Onthe history of kalam, see further S. Schmidtke (ed.), The Oxford Handbook of Islamic Theology (Oxford, 2016) and J. van Ess, Theology and Society in the Second and the Third Centuries ofthe Hijra: A History of Religious Thought in Early Islam, 5 vols., tr. from German by J. O'Kane, G. Goldbloom, R. Otto (Brill: 2017-2020).

9 Further references on the formative period of post-Avicennan philosophy include A. Shihadeh, “From al-Ghazali to al-Razi: 6th/12th Century Developments in Muslim Philosophical Theology” Arabic Sciences and Philosophy 15 (2005): 141-179.

Avicenna.!° Bahmanyar's most widely read treatise is al-Tahsil (The Attainment), a reorganized and comprehensive epitome of Avicenna's teachings. Al- Tahsil provides us with an overview of what has been recognized as Avicennism in post-Avicennan philosophy. Another of his treatises from which we quote is Fr mawdü' ‘ilm ma bad al-tabi‘a (On the Subject-Matter of Metaphysics), which again demonstrates Bahmanyar's close adherence to Avicenna’s philosophy.

Alongside Bahmanyar, the next important philosopher usually connected with Avicenna's school is ‘Umar al-Khayyam (d. 1123/24). Although al- Khayyam is mostly known in contemporary scholarship as a poet and mathematician, he has written several short treatises in metaphysics and philosophy of religion, such as Risāla ft al-wujūd (Epistle on Existence), al-Jawab ‘an thalath mastil (Response to Three Questions), Risālat al-diyā” al-'aglī (Epistle of Intellectual Radiance), and Kawn wa-taklif (Generation and Obligation). Al-Hayyam discusses in them various questions, such as distinction between essence and existence, God's essence, the nature of evil, and the nature of religious obligation in the determinist world. Al-Khayyam consistently defends Avicennan doctrine, albeit with further developments, as in the case of the conceptual distinction between essence and existence. Among the treatises listed above, al-Khayyam’s Risāla ft al-wujud stands out as an attempt to address the metaphysical views of Mu'tazilite kalam from the standpoint of Avicenna's philosophy.

The final representatives of Avicenna's school live in the first half of the twelfth century. They are ‘Umar ibn Sahlan al-Sawi (d. ca. 1145) and Sharaf al- Zaman al-Ilaqi (d. 1141). Of these two, the latter seems to be rather a minor figure, possibly due to our lack of sources, or because of his execution following the sultan Sanjar's defeat at the battle of Qatwan. The only work by al-Īlāgī quoted in this volume is his brief response to Taj al-Din al-Shahrastani (d. 1153) on the nature of God's knowledge, in which al-Īlāgī seems to express even more radical denial of God's knowledge than Avicenna would be willing to do himself. Like al-Īlāgī, al-Sawi also engaged in philosophical correspondence with al- Shahrastānī, but unlike al-Īlāgī, al-Sawi seems to have been a far more influential figure. This can be seen, for instance, from the mentions of al-Sawi in al-Suhrawardīs treatises. Among al-Sāwī's own treatises, al-Basa’ir al-Nasiriyya (Insights for Nasir al-Din) bears close similarity in method and

10 See further J. Janssens, "Bahmanyār ibn Marzuban: A Faithful Disciple of Avicenna,’ in: D.C. Reisman and A.H. al-Rahim (eds.), Before and After Avicenna: Proceedings of the First Conference of the Avicenna Study Group (Leiden-Boston: 2003), 177-198.

in content to Bahmanyar's al-Tahsil and can be used as a helpful overview of Avicennism as it was seen in the twelfth century. Still more important, arguably, are al-Sāwīs shorter treatises, which were designed as responses to two critics of Avicenna of his time, Abt al-Barakat al-Baghdadi (d. ca. 1165) and the aforementioned al-Shahrastani. One of these treatises is Nahj al-taqdis (The Way to Sanctification), in which al-Sawi attempts to support Avicenna's denial of God's knowledge of particulars as such. (He may be the last person in the post- Avicennan tradition to do this.) Another is al-Sāwīs response to al- Shahrastani on the nature of God's essence, which was given the title of Musara'at al- Musara‘a (The Wrestling Match with the Wrestling Match) by a copyist, due to the similarity of al-Sahrastàni's argumentation in this epistolary exchange with al- Shahrastanr' treatise al- Musaraat al-falasifa (The Wrestling Match with the Philosophers).

Bahmanyar, al-Khayyam, al-Sāwī, and al-Īlāgī are the four main representatives of purely Avicennan falsafa in the formative period of post-Avicenna philosophy. Probably even more important for the formation of post- Avicennan philosophy, though, are their opponents, the scholars of kalam who extensively engaged with Avicenna’s philosophy, criticized it, and used it in the development of their own thought. The most famous among them is, of course, Abu Hamid al-Ghazali (d. 1111), who was allegedly responsible for the perishing of philosophy in the world of Islam, according to traditional orientalist narratives. Although this account has been widely dismissed, the importance of al-Ghazali for the later generations is not subject to doubt. Al- Ghazali's famous treatise Tahafut al-falasifa (The Incoherence of the Falsafa- Philosophers) helped to set the questions that would typically be contested between partisans of kalam and proponents of falsafa, such as God's essence and God's knowledge of particulars. Also important is al-Ghazali’s treatise Iqtisad al-i'tiqad (Moderation in Belief), which will be used in this volume as a rich source of the traditional Ash'arite views on various philosophical questions.

Al-Ghazālīs critique of Avicenna's philosophy from a kalam perspective found several followers. One of them is Ibn Ghaylan al-Balkhi (d. ca. 1194), the author of the treatise Huduth al-‘alam (The Temporal Origination of the World). For the purposes of this volume, this treatise will be important as an expression of Ibn Ghaylan’s metaphysical views on essence and existence, God's essence, and universals, in which he appears to be close to al-Shahrastani. Another staunch opponent of everything Avicennan is Sharaf al-Din al-Mas'udi (d. ca. 1194). Al-Mas'üdi might have been the first in the long tradition of commentators on Avicenna's treatise al-Isharat wa-al-tanbihat (Pointers and Reminders), with his al-Mabahith wa-al-shukük ‘ala kitab al-Isharat wa-l-tanbthat