The works in the Central Works of Philosophy volumes have been chosen because of their fundamental importance in the history of philosophy and for the development of human thought. Other works might have been chosen; however, the underlying idea is that if any works should be chosen, then these certainly should be. In the cases where the work is a philosopher's magnum opus the essay on it gives an excellent overview of the philosopher's thought.

Chapter 1 by Hugh Benson presents the central theme of Plato's Republic, that of the nature of justice. The Republic stands as arguably the most important work of Western philosophy. It is a pivotal work in Plato's thought, presenting a well worked out culmination of previous ideas, following which he subjected those ideas to considerable critical analysis, although he did not abandon them.

Chapter 2 by Paula Gottlieb discusses Aristotle's Nichomachean Ethics, central to understanding the key Greek idea in ethics of eudaimonia, usually translated “happiness”. However, happiness here refers not to a subjective state of pleasure, but to aretē or virtue, whereby our actions should be guided by what truly contributes to our well-being or excellence as the kind of creatures that we are.

Chapter 3 by Harry Lesser gives an account of Lucretius's On The Nature of the Universe, which takes the form – not unusual for the time – of an extended philosophical verse.

Introduction: text and context

The Enneads of Plotinus (204–70 CE) would, in modern terms, be better entitled The Collected [or even Complete] Works of Plotinus, arranged and introduced by Porphyry of Tyre. By his sometime pupil Porphyry's own account, Plotinus began to write down summaries and expansions of seminar discussion in his early fifties, and continued to write until shortly before his death. Having weak eyes, he could never bear to re-read or revise his work, and his colleagues and students might reasonably have doubted whether every copy had been properly proofread. Thirty years after Plotinus's death, Porphyry produced what then became the definitive edition of the works (wholly superseding the “hundred volumes” of Amelius and the edition of Eustachius). Porphyry chose to ensure that there were precisely 54 treatises, collected in six groups of nine (hence Enneads, from the Greek term ennea), even if he had to divide continuous stretches of philosophical enquiry (sometimes in mid-sentence), or elevate minor notes into treatises to achieve the number. He also took care to provide the order of writing, as far as he could know it. Later scholars have not always agreed that the Porphyrian order is the best approach to Plotinus, but no better arrangement has achieved canonical status, unless perhaps the Arabic version known as The Theology of Aristotle, which carried neo-Platonic thought into the heart of Islam. The Theology consists of edited selections from the treatises contained in Enneads IV-VI (see Adamson 2003).

In many general histories of philosophy, Anselm's role is that of inventing the so-called Ontological Argument for the existence of God, which occupies about two pages in Chapters 2 and (some say) 3 of his Proslogion. The remaining 300 or so pages of close argument that make up his philosophical and theological writings are largely ignored, including the rest of the Proslogion itself. One purpose of this essay is to right that imbalance, at least as far as the Proslogion is concerned. The other chapters of the Proslogion are full of exciting philosophical discussion, on topics as varied as omnipotence, justice and eternity. Both Anselm's aims and his originality are obscured when the focus is concentrated on two brief chapters at the beginning of the book. Yet it would be a mistake to ignore entirely the special status of the Ontological Argument. It is not an accident that the shape of its reasoning has fascinated philosophers down the generations, and Anselm himself gave it special weight by including with the Proslogion the criticisms of this argument made by a contemporary, Gaunilo, a monk of Marmoutiers, along with his own replies to them.

Anselm's times and the background to the Proslogion

Anselm, who was born in 1033 and died in 1109, lived on the eve of one of the most brilliant periods of Western philosophy.

Introduction: Lucretius's method

Titus Lucretius Carus, to give him his full name, lived probably from 99 to 55 BCE. Virtually nothing is known of his life, or why he died young; there is no reason to believe the story that he was driven mad by a love potion and committed suicide. He was probably of aristocratic birth, married, and a fairly prosperous farmer, prosperous enough not to have to work on the farm with his own hands, but not so prosperous that he could employ a bailiff. There are references in his poem to the management of the farm keeping him very busy, so that he could find time for writing only at night. His work consists of one long philosophical poem, De rerum natura, literally, “On the Nature of Things”, but often translated, more philosophically, as “On the Nature of the Universe”, unfinished at his death but already in six books and over 7000 lines. This poem is the most complete account we have of the philosophy of Epicurus (341–271 BCE), because all that survives of the works of Epicurus himself are three letters, two collections of aphorisms and an account of his “Principal Doctrines”, plus fragments and later reports of what he wrote.

These writings provide evidence that Lucretius largely stayed very close to Epicurus, and often simply put his doctrines and arguments into poetry.

Introduction

Ockham's Summa logicae (The Logic Handbook), written c. 1323, is a manifesto masquerading as a textbook. Its aim, Ockham disingenuously declares in his Preface, is merely to help beginning students in theology avoid elementary difficulties in logic. His undeclared aim is far more ambitious. In the Summa logicae Ockham puts forward a new philosophical programme designed to supersede the views of his contemporaries and predecessors, views that come in for extensive and trenchant criticism in the course of its many pages. We call that programme and the movement it engendered “nominalism”. Its guiding principle is the conviction that only concrete individuals exist, and hence that any other purported entities are no more than names (nomina), traditionally expressed as the maxim not to multiply entities beyond necessity, a formulation known as “Ockham's razor”. This principle has a wide range of application, and it has deep theological as well as philosophical consequences. The Summa logicae lays out in systematic detail Ockham's account of logic and language, providing him with the necessary groundwork for applying his razor.

Ockham's goal in the Summa logicae, then, is to expound and promote his nominalist programme in the context of developing a rigorous account of logic and language.

SUHRAWARDĪ AND HIS CAREER

One is tempted to romanticize Suhrawardī. Indeed, there is no particular reason to avoid romanticizing him as a personality. He lived the life of a wandering wise man, and his story involved a prince, a magic gem, the fabulous Saladin, and a tragic early death. We can see him as his contemporaries saw him - probably as he saw himself - as a figure out of philosophical folklore, the like of whom had not been seen since Apollonius of Tyana. However, in my view it is a grave error to examine his philosophy, Illuminationism, through romantic spectacles, for Suhrawardi, despite his own attempts to mystify his project, was a hardheaded philosophical critic and creative thinker who set the agenda for later Islamic philosophy. Al-Ghazāli’s attempt to make religion independent of reason and Averroes' Aristotelianism left little trace in later Islamic thought, but Suhrawardi’s critique of Avicenna’s ontology and of Aristotelian epistemology and his solutions to these problems were his successors' starting points. The modern description of his philosophy as “theosophy” does not do justice to the rigor and philosophical influence of his thought.

Suhrawardī was probably born around 1154 in the village of Suhraward near Zanjān in northwestern Iran. We know nothing of his family or ethnic background. He first appears in Marāgha, a nearby city, where he studied logic and philosophy with Majd al-Dīn al-Jīlī, a scholar of moderate prominence who also was the teacher of the famous theologian Fakhr al-Dīn al-Rāzī.

In a monotheistic culture of the “examined and contemplative life,” the central intellectual challenge for a thinking, experiencing believer is to address the question: how can I know God? and concomitantly, how can I know what God means? In the classical period, Muslim thinkers approached this question by delineating four possible paths toward realizing, understanding, internalizing, and implementing the “truth” or “reality.” These four ways are succinctly and importantly examined in the famous “autobiography” of the theologian and Sīfī Abū Hāmid al-Ghazālī (d. 1111), al-Munqidh min al-dalāl (The Deliverer from Error): the imitation of infallible authoritative example (ta'līm, following the infallible Shī'ite Imām), acceptance of prophetic traditions and norms (taqlid of the Sunna), rational and discursive argument ('aql, naz. ar), and ineffable “pure” experience or “taste” (dhawq). So the first question that needs to be considered is the method of acquiring truth and certainty. In the context of this chapter, the options that I shall consider are reason and experience. In al-Ghazālī’s account, the use of philosophical reason is denounced for its failure to conform to “revealed truths,” while mystical experience is lauded: the difference is, as he puts it, that reason is an indirect means of acquiring truth through the verification of arguments, while “taste” experiences and directly takes on the state of truth, effecting a critical complementarity between knowledge and action. “Taste” has the added advantage of being a Qur’ānic concept and became the commonplace nomenclature for experience in Sīfī circles. Thus it would seem that early on in Islam, we find reason and experience pitted against each other.

In this chapter I will discuss Arabic and Persian philosophical trends as presented in texts mainly from the sixteenth and seventeenth centuries and their more recent continuation. Philosophical activity continued especially in the lands marked by the geopolitical boundaries of Persianate influence, centered in the land of Iran as marked since the Safavid period beginning in 1501. Of the philosophers in the earlier, formative period of Arabic philosophy, it was Avicenna whose works made the most direct and lasting impact on all subsequent philosophical trends and schools. The structure, techniques, and language of Avicenna’s philosophy - best exemplified in his two main works, al-Ishārāt wa al-tanbīhāt and al-Shifā' - define a holistic system against which all subsequent philosophical writings, in both Arabic and Persian, are measured. Avicenna’s philosophical texts give Arabic and Persian Peripatetic philosophy its technical language and methodology, as well as setting out a range of philosophical problems in semantics, logic, ontology, epistemology, and so on. Later trends must be regarded as refinements and developments from within philosophical texts already established by the twelfth century C.E.

In the history of Western philosophy the role played by texts written in Arabic is crucial. This can be seen from the sheer volume of works that were translated (see the table that follows this chapter). We have hints of Arabic-speaking teachers of philosophy. Adelard of Bath (fl. 1116-50) speaks of his studia Arabica/Arabum studia (in reference to natural philosophy) and magistri, which he probably encountered in southern Italy and Sicily. Stephen of Pisa (fl. 1127), who wrote on cosmology in Antioch, expresses his debt to “a certain Arab.”Kamal al-Din ibn Yunus of Mosul (d. 1242), the greatest Muslim teacher of his time, in turn, boasted of Christians among his pupils; one of Ibn Yunus' pupils, Siraj al-Din Urmawi, became a member of Frederick II Hohenstaufen’s household and wrote a book on logic for him. Andrea Alpago (d. before 1546) acquired knowledge of Avicenna’s psychology from the Shī'ite scholar Muhammad ibn Makkī Shams al-Dīn al-Dimashqī (d. 1531) in Damascus. But it is through the surviving Arabic texts and their translations that we can best gauge the extent of the impact of Arabic philosophy. The works translated reflect the various genres current in Arabic.

From the first incursion of Islam into Spain in 710 until the eventual success of the Christian reconquest in 1492, the Iberian peninsula was partially or wholly under Muslim rule, the westernmost outpost of a sprawling Muslim empire. For many decades the intellectual and cultural climate of “al-Andalus” was thus subsidiary to that of the East. Philosophy was no exception: it came first from the East, but in time acquired an autonomous life. This is reflected in the history of Andalusian philosophy, which at first followed in the footsteps of al-Fārābī and Avicenna, but soon developed along two very different paths. On the one hand, the Andalusians took up al-Fārābī’s project of reconstructing and further developing the thought of Aristotle, a process that would culminate in the commentaries of Averroes. On the other hand, Andalusian philosophers were attracted by Sūfism. Most prominently, the mystic Ibn ‘Arabī hailed from al-Andalus. But as will be indicated below, even authors who worked within the falsafa tradition were not immune to the appeal of the Sūfīs. This chapter will illustrate these competing traditions in the thought and writings of the two most significant Muslim philosophers of al-Andalus prior to Averroes: Ibn Bājja (known as Avempace to the Latins) and Ibn Tufayl.

LIFE AND WORKS

The philosophy of al-Fārābī stands in marked distinction to that of al-Kindī but is no less representative of the major trends of thought inherited by the Islamic world. His tradition is consciously constructed as a continuation and refinement of the neo-Aristotelianism of the Alexandrian tradition, adapted to the new cultural matrix of the Near East. The Neoplatonic element of al-Fārābī ’s thought is most obvious in the emanationist scheme that forms a central part of his cosmology, though that scheme is much more developed than that of earlier Neoplatonists in its inclusion of the Ptolemaic planetary system. His theory of the intellect appears to be based on a close reading of Alexander of Aphrodisias and develops the concept of an Active Intellect standing outside the human intellect. Above all, al-Fārābī ’s legacy to later thinkers is a highly sophisticated noetics placed within a rigorous curriculum of instruction in Aristotelian logic. Fārābī was above all a systematic and synthesizing philosopher; as such, his system would form the point of departure on all the major issues of philosophy in the Islamic world after him.

The status accorded al-Fārābī’s intellectual legacy here stands somewhat at odds with what we can reconstruct of his life with any certainty. With the exception of a few simple facts, virtually nothing is known of the personal circumstances and familial background of al-Fārābī. The great variety of legends and anecdotes about this second major philosopher of the Islamic period is the product of contending biographical traditions produced nearly three centuries after his death.

Metaphysics, first philosophy, or divine science has always been a subject of controversy. Too often medieval Arabic metaphysics is regarded as either simply a paraphrase of or a commentary on Aristotle’s Metaphysics, or a curious and rather unsuccessful blend of Aristotelian metaphysics and Neoplatonism. Cristina D'Ancona has shown the superficiality of this latter approach by highlighting how carefully and creatively the “falāsifa” or Hellenizing philosophers used the various Greek sources, such as the works of Aristotle, the Plotiniana Arabica (a group of texts based on Plotinus and including the so-called Aristotle’s Theology derived from Enneads IV-VI), and the Liber de Causis, adapted from Proclus' Theology and known in Arabic as The Book of the Pure Good. Yet Greek sources are not enough to explain some developments. In 1979 Richard Frank argued that falsafa (the Arabic transliteration of the Greek term for philosophy, highlighting its foreign origin) is not immune to the influence of kalāmor Islamic theology, which had elaborated an ontology of its own. More recently, though controversially, he has argued that even al-Ghazālī, the famous author of the Incoherence of the Philosophers and the staunch protector of orthodox Sunni Islam, is himself deeply influenced by Avicenna.

The scope of this chapter is dauntingly broad, since Avicenna was the central figure in the history of Arabic-Islamic philosophy. Before Avicenna, falsafa (Arabic Aristotelian and Neoplatonic philosophy) and kalām (Islamic doctrinal theology) were distinct strands of thought, even though a good deal of cross-fertilization took place between them. After Avicenna, by contrast, the two strands fused together and post-Avicennian kalām emerged as a truly Islamic philosophy, a synthesis of Avicenna’s metaphysics and Muslim doctrine.

To talk about the sources, evolution, and influence of Avicenna’s ideas is, in fact, to talk about over two thousand years of philosophical activity. Avicenna’s sources begin with Aristotle in the fourth century B.C.E. and include the late antique Greek Aristotle commentators, both Peripatetic and Neoplatonist. Avicenna himself was extremely prolific: between 40 and 275 titles have been attributed to him by bibliographers ranging from his student Jūzjānī to the late Egyptian scholar Georges Anawati, with approximately 130 reckoned to be authentic by the Iranian scholar Yahyā Mahdavī. What is more, his ideas evolved during the course of his career,with the result that, as with Plato’s and Aristotle’s thought, Avicenna’s philosophy will often resist our attempts to systematize it, and his position on a number of important philosophical issues will appear frustratingly underdetermined. As for Avicenna’s impact, it was felt acutely in both the Islamic world and in Christian Europe.

THE BEGINNINGS OF MEDIEVAL JEWISH PHILOSOPHY

The broadest periodization of medieval philosophy, in general, and of medieval Jewish philosophy, in particular, begins with Philo in the first century and comes to an end with Spinoza in the seventeenth century. This is the well-known periodization of Harry A. Wolfson, who explains:

Wolfson was in a sense correct. The problems and concerns of Philo were to a great extent those of the medieval philosophers. Yet, while it is helpful to think of the philosophy of Philo as the “Foundations of Religious Philosophy in Judaism, Christianity, and Islam,” virtually all datings of medieval philosophy begin centuries later and in the case of medieval Jewish philosophy nearly a millennium later. The resistance of scholars to beginning medieval Jewish philosophy with Philo is not simply a result of their discomfort with beginning the medieval period in the first century. More importantly, if one begins medieval Jewish philosophy with Philo, there is no continuity. From Philo to the ninth century, there are no writings that may be considered Jewish philosophy. Moreover, although Wolfson can speak of the recurrence of Philonic views in post-Philonic Islamic and Jewish philosophy, Philo – as far as we know – was not translated into Arabic or Hebrew and accordingly had no direct influence upon Jewish philosophers until the Renaissance.

Abū al-Walid Muhammad ibn Ahmad ibn Muhammad ibn Rushd (ca. 1126-98), who came to be known in the Latin West as Averroes, was born at Cordoba into a family prominent for its expert devotion to the study and development of religious law (shar'īa). In Arabic sources al-Hafīd (“the Grandson”) is added to his name to distinguish him from his grandfather (d. 1126), a famous Malikite jurist who served the ruling Almoravid regime as qādī (judge) and even as imām (prayer leader and chief religious authority) at the magnificent Great Mosque which still stands today in the city of Averroes' birth and where Averroes himself served as Grand Qādī (chief judge). When the governing regime changed with the success of 'Abd al-Mu'min (r. 1130-63), founder of the Almohad (al-Muwahhidūn) dynasty, the members of the family continued to flourish under a new religious orientation based on the teachings of the reformer, al-Mahdī ibn Tumart (d. ca. 1129-30). Although insistent on the strict adherence to religious law, Ibn Tūmart’s teachings were at the same time equally insistent on the essential rationality of human understanding of the existence and unity (tawhīd) of God and his creation as well as the rationality of the Qur'ān and its interpretation. This approach was embraced – even exploited – by Averroes in his own writings on dialectical theology and thereby played a role in the development of his thought on the nature of religious law and revelation in relation to philosophy founded on the powers of natural reason.