Abu Hamid Muhammed ibn Muhammed al-Ghazali, known in the Latin West as Algazel, did not consider himself to be a philosopher, but rather a jurist and theologian who came to reject rational philosophy.
Al-Ghazali was born in 1058 in Tus in the Persian province of Khorasan, the son of a Sufi, an Islamic mystic. His father died when he was young, leaving him and his brother Ahmad to be cared for by a family friend. When al-Ghazali was twelve he and his brother went to Jurjan to enroll in a madrasa, where he studied religious law for seven years before returning to Tus. Around 1080 he went to Nishapur, the provincial capital, to study theology – kalam – with the noted Imam al-Haramayn al-Juwayni. After the death of al-Juwayni in 1085 al-Ghazali became associated with the court of Nizam al-Mulk, the powerful vizier of the Seljuk sultan Jalal al-Din Malikshah, who in 1091 appointed him as professor of religious law at the Nizamiyyah madrasa at Baghdad. He taught there for four years and also made an intensive study of philosophy, including the works of al-Farabi and Ibn Sina as well as those of his Islamic predecessors. As he writes of this in his autobiography, The Deliverance from Error: ‘By my solitary reading during the hours thus snatched God brought me in less than two years to a complete understanding of the science of the philosophers.’
During al-Ghazali’s tenure in Baghdad he wrote a number of philosophical works, most notably The Incoherence of the Philosophers. He says in his autobiography that he was led to write this book by the errors and heresies of earlier philosophers from Aristotle to al-Farabi and Ibn Sina, the principal interpreters of Aristotelian ideas in the Islamic world. Referring to Plato and Aristotle, he writes that ‘We must therefore reckon as unbelievers both those philosophers themselves and their followers among the Islamic philosophers, such as Ibn Sina, al-Farabi and others; in transmitting the philosophy of Aristotle, however, none of the Islamic philosophers has accomplished anything comparable to the achievement of the two men named.’
Al-Ghazali identified the ‘philosophical sciences’ as mathematics, logic, natural science, philosophy, theology, metaphysics, politics and ethics. His view was that mathematics and logic were not ‘connected with religious matters, either to deny or affirm them’. So far as natural science, philosophy or physics were concerned, his main objections to the theories of the philosophers was that they did not recognise that nature is subject to divine command. ‘The basis of all these objections is the recognition that nature is in subjection to God most high, not acting of itself but serving as an instrument in the hands of its Creator. Sun and moon, stars and elements, are in subjection to His Command. There is none of them whose activity is produced by or proceeds from its own essence.’
Al-Ghazali believed that ‘most of the errors of the philosophers’ occur in theology or metaphysics. He particularly criticised Aristotelian positions of al-Farabi and Ibn Sina, writing that ‘They were unable to satisfy the conditions of proof they lay down in logic, and consequently differ much from one another here.’ He went on to say that ‘The views of Aristotle, as expounded by al-Farabi and Ibn Sina, are close to those of the Islamic writers. All their errors are comprised under twenty heads, on three of which they must be reckoned infidels and on seventeen heretics. It was to show the falsity of their views on these twenty points that I composed The Incoherence of the Philosophers.’
Al-Ghazali writes in his autobiography that when he completed his study of the philosophical sciences he was still not satisfied. ‘By the time I had done with the science of philosophy – acquiring an understanding of it and marking what was spurious in it – I had realised that this too did not satisfy my aim in full and that the intellect neither comprehends all it attempts to know nor solves all its problems.’ He goes on to say that his dissatisfaction with the philosophical sciences led him to the study of mysticism. ‘I knew that the complete mystic “way” includes both intellectual belief and practical activity; the latter consists in getting rid of the obstacles in the self and in stripping off its base characteristics and vicious morals, so that the heart may attain to freedom from what is not God and to constant recollection of Him.’
Toward the end of his tenure in Baghdad al-Ghazali underwent a spiritual crisis, feeling that his way of life was too worldly to give him any hope of eternal reward. This led him to abandon his teaching career and leave Baghdad in 1195 to adopt the ascetic life of a wandering Sufi, going first to Damascus and then to Jerusalem. He then made the pilgrimage to Mecca and went on to Medina, after which he returned to Persia before 1099. He continued to live in obscurity until 1106, when Fakhr al-Mulk, vizier of the Seljuk sultan Sanjar, persuaded him to resume teaching at the Nizamiyyah madrasa in Nishapur. Al-Ghazali’s second period of teaching lasted for just two years, after which he returned to Tus, where he died in December 1111.
Toward the end of his life al-Ghazali, in a letter to Sultan Sanjar, mentioned that he had written more than seventy works. His major works comprise eight in theology, including The Deliverance from Error; six in Sufism; five in philosophy, including The Incoherence of the Philosophers; and five in jurisprudence. Most of his works were written in Arabic and a few in Persian. His most important work in Persian is The Alchemy of Happiness. This is a shorter version of a four-volume treatise on Sufism in Arabic entitled The Revival of the Religious Sciences, which is generally considered to be one of al-Ghazali’s greatest works. Here his concept of divine creation has been said to resemble Leibniz’s notion of the ‘best of all possible worlds’, where al-Ghazali writes that ‘Everything which God apportions to man...is...pure right, with no wrong in it. Indeed, it is according to the necessarily right order, in accord with what must be and as it must be and in the measure in which it must be, and there is not potentially anything more excellent and more complete than it.’
The decline of Arabic science that began in the twelfth century is sometimes attributed at least partly to Al-Ghazali’s influence. Nevertheless, Arabic work in mathematics, mechanics and astronomy, at least, remained at a high level long after his time, particularly in Central Asia.
Abu l-Walid Muhammad ibn Ahmad ibn Muhammad ibn Rushd (1126–98), the Latin Averroës, who was from a distinguished family of Cordoban jurists would also have a profound effect on Arabic philosophy. Ibn Rushd, was named for his grandfather, who was imam of the Great Mosque and also qadi, a position his father also held. He studied theology, law, medicine and philosophy, particularly the works of Aristotle, which he read in Arabic translation.
Ibn Rushd was in Marrakech in 1152, during the reign of the Almohad ruler ‘Abd al-Mu’min, when he seems to have made his first astronomical observations. There he met Ibn Tufayl, who would later play an important part in his life by introducing him to Caliph Abu Ya’qub Yusuf. According to al-Marrakushi, the caliph had complained to Ibn Tufayl about his difficulty in reading the works of Aristotle and the need for a commentary to explain them. Ibn Tufayl said that he himself was too old and busy to do the job, and so he recommended Ibn Rushd, who was thus led to begin his monumental series of commentaries on the works of Aristotle.
After the death of Ibn Tufayl, Ibn Rushd became personal physician to Abu Ya’qub Yusuf and was appointed qadi, first in Seville, then in Cordoba, and then again in Seville. He retained his posts under Abu Ya’qub Yusuf’s son and successor Abu Yusuf Ya’qub al-Mansur (r. 1184–99), though in 1195 the caliph confined him for two years to the town of Lucena, near Cordoba, because orthodox Islamic scholars had condemned his philosophical doctrines. Early in 1198 the caliph lifted the ban and took Ibn Rushd with him to his court at Marrakech. But Ibn Rushd had little time to enjoy his freedom, for he died in Marrakech on 10 December of that year, after which his body was returned to Cordoba for burial.
Most of the philosophical writings of Ibn Rushd can be divided into two groups, his commentaries on Aristotle and his own treatises on philosophy. His commentaries on Aristotle, thirty-eight in number, are of three types, the so-called Short, Middle and Long Commentaries. The Short Commentaries, generally considered to be early works, comprise summaries of Aristotle’s ideas, usually based on the Greek commentators. The Middle Commentaries are usually simplified paraphrases of Aristotle’s writings, and are thought to have been written in response to the request of Ibn Ya’qub Yusuf. The Long Commentaries, Ibn Rushd’s mature works, deal with the entire Aristotelian corpus, beginning with the Posterior Analytics, followed by De nima, the Physics, De Caelo and the Metaphysics. His commentaries were translated into Latin in the thirteenth century, and influenced some of the leading intellectual figures in Europe at the time, most notably Albertus Magnus and Thomas Aquinas. Thomas Aquinas in particular assimilated the Aristotelianism of Averroës, as he was known in Latin, and worked it into a system of thought that was theologically acceptable to the Catholic Church.
Ibn Rushd’s own philosophical works include the Decisive Treatise on the Harmony between Religion and Philosophy, the Exposition of the Methods of Demonstration Relative to the Religious Dogmas and to the Definition of the Equivocal Meanings and Innovations Encountered in the Process of Interpretation and which alter the Truth and Error and the famous Incoherence of the Incoherence of the Philosophers.
The second of these treatises was intended as a sequel to the first, and Ibn Rushd noted that his aim in the two works was ‘the examination of the external aspect of the beliefs which the lawgiver [i.e., Muhammad] intended the public to adhere to’, as distinct from the false beliefs they had been led into by theologians. He said that by ‘external beliefs’ he meant those ‘without which the faith [of the believer] is not complete’.
The Incoherence of the Incoherence was written in opposition to al-Ghazali’s attack on the works of al-Farabi and Ibn Sina, the two leading Muslim interpreters of Aristotle. Ibn Rushd, in his defence of Aristotelianism, argued that al-Gazali’s attacks on al-Farabi and Ibn Sina were mistaken, besides which their ideas often deviated from those of Aristotle. This was in keeping with Ibn Rushd’s effort to resolve the dispute between Islamic theologians and philosophers, as he tried to reconcile apparent contradictions between law and philosophy.
Ibn Rushd’s commentaries attempted to restore Aristotle’s own ideas in Islamic thought and to supplant the Neoplatonism of al-Farabi and Ibn Sina. He regarded the philosophy of Aristotle as the last word, to the extent that truth can be understood by the human mind.
One of the points on which al-Ghazali had criticised the philosophers in their interpretation of Aristotle, most notably al-Farabi and Ibn Sina, was their denial of the divine creation of the world at some moment in time, for this would have meant that something temporal emerged from the eternal, which is inconceivable. Ibn Rushd quotes al-Ghazali’s statement of the arguments of the philosophers: ‘At one moment the object of will did not exist, everything remained as it was before, and then the object of will existed. Is this not a perfectly absurd theory.’ Al-Ghazali, addressing the philosophers, asks them what is wrong with the notion of divine creation:
Why do you deny the theory of those who say that the world has been created by an eternal will which has decreed its existence in the time in which it exists, its non-existence lasting until the time it ceases and its existence beginning from the time it begins, while its existence was not willed before and therefore did not happen, and that at the precise moment it began it was willed by an eternal will and so began? What is the objection to this theory, and what is absurd in it?
Al-Ghazali then wonders whether the divine will might not be similar to that of humans, who often decide to do something but delay the implementation of their decision. He gives the example of a man who decides to divorce his wife but does not actually do so until she has committed an offence that gives him the legal basis for his action. As Ibn Rushd puts al-Ghazali’s argument:
In the same way as the actual divorce is delayed after the formula of the divorce till the moment when the condition of someone’s entering the house, or any other, is fulfilled, so that the realisation of the world can be delayed after God’s act of creation until the condition is fulfilled on which this realisation depends, i.e., the moment when God willed it. But conventional things do not behave like rational things.
Al-Ghazali goes on to suggest that the divine will is actually very dissimilar to that of humans, so that arguments in which the philosophers draw comparisons between the two are invalid. Ibn Rushd ridicules this criticism, saying that the philosophers have tried to demonstrate logically the impossibility of an eternal will being involved in a temporal creation, and that al-Ghazali is absolutely wrong in suggesting that their objection to divine creation is based on intuition rather than on valid arguments.
Ibn Rushd in his mature work rejects the Neoplatonist cosmology of emanation that had been held by al-Farabi and Ibn Sina, in which the heavenly intelligences emanate from the First Being in the outermost celestial sphere as far as the innermost sphere of the moon, where the Active Intellect endows material bodies with their form. He criticises al-Farabi and Ibn Sina for attributing the emanation theory to Aristotle and thus distorting his whole teaching. Roger Arnaldez writes of how Ibn Rushd rejected the Neoplatonist view of emanation in favour of the Aristotelian theory in which ‘he explained that the First Mover moves the world not by a sort of attraction, but by his commandment, like a king seated on his throne who has no need himself of moving in order to act’.
Ibn Rushd believed that there can be no essential conflict between philosophy and religion, that is to say, reason and revelation, which he regarded as different avenues to the same truth. He believed that where there seems to be an apparent conflict then careful study of Scripture, that is, the Kuran and the hadith, will show that an allegorical interpretation will resolve the difference. ‘We affirm definitely that whenever the conclusion of a demonstration is in conflict with the apparent meaning of Scripture, that apparent meaning admits of allegorical interpretation according to the rules for such interpretation in Arabic.’
The conflict between reason and revelation flared up in Western Europe after Ibn Rushd’s Aristotelian commentaries were translated into Latin. It was soon realised that some of his ideas, such as the eternity of the world, were contrary to Christian belief. This gave rise to the term ‘Latin Averroism’, particularly applied to the thirteenth-century philosopher Siger of Brabant. Siger held that the logical conclusions of reason may be contrary to the truths revealed in religion, nevertheless both must be accepted, a notion that came to be called the theory of ‘double truth’.
Ibn Rushd accepted Aristotle’s planetary model of the homocentric spheres and rejected Ptolemy’s theory of eccentrics, epicycles and equants. He writes of his astronomical researches in his commentary on Aristotle’s Metaphysics, where he expresses his belief that the prevailing Ptolemaic theory is a mathematical fiction that has no basis in reality.
In my youth I hoped it would be possible for me to bring this research [in astronomy] to a successful conclusion. Now, in my old age, I have lost hope, for several obstacles have stood in my way. But what I say about it will perhaps attract the attention of future researchers. The astronomical science of our days surely offers nothing from which one can derive an existing reality. The model that has been developed in the times in which we live accords with the computations, not with existence.
Aristotle had included fifty-five spheres in his model of the celestial motions. Ibn Rushd says that in his time astronomers set this number at fifty, while he himself used forty-five. But at the same time he wrote: ‘As to a profound examination of what is necessarily and really involved in this question, we leave it to those who devote themselves more completely to this art, those who dedicate themselves entirely to it and who concern themselves with nothing else.’
In his commentary on Aristotle’s Physics, Ibn Rushd attacked Ibn Bajja’s theory of motion, specifically the idea that the medium impeded natural motion. Instead he supported Aristotle’s theory, in which the velocity of a body is proportional to the force acting on it divided by the resisting force of the medium.
According to Ernest A. Moody, Ibn Rushd was the first to define force as ‘the rate at which work is done in changing the kinetic condition of a moving body’, and also the first to state ‘that the effect and measure of a force is change in the kinetic condition of a materially resistant mass’. These are perhaps some of the clearest statements about the effect of force on motion before the Scientific Revolution of the seventeenth century. Ibn Rushd also seems to have asserted that bodies have an inherent resistance to a change in their state of motion, the concept that came to be known as inertia. But he attributed this inertia only to the celestial spheres, to explain why they do not move with infinite speed when they are set in motion by the Prime Mover, as they would according to Aristotle’s theory, for there would otherwise be no resistance to slow them down in the heavens.
One of Ibn Rushd’s Aristotelian commentaries, the Epitome of the Parva Naturalis, supports Aristotle’s intromission theory of light, in which vision is due to light passing from the luminous object to the eye, rather than the other way round, as in the extramission theory. One passage describes the transmission from the object through the air and the various coatings of the eye. ‘We maintain that the air, by means of light, receives the forms of objects first and then conveys them to the external coat of the eye, and the external coat conveys them to the remaining coats, until the movement reaches the innermost coat behind which the common sense is located, and the latter perceives the form of the object.’ Another passage identifies the retina as the basic photosensitive organ in the eye, a notion that was revived by the anatomist Felix Platter (1536–1615).
The innermost of the coats of the eye [i.e., the retina] must necessarily receive the light from the humors of the eye, just as the humors receive the light from the air. However, inasmuch as the perceptive faculty resides in the region of this coat of the eye, in the part which is connected with the cranium and not in the part facing the air, these coats, that is to say the curtains of the eye, therefore protect the faculty of the sense by virtue of the fact that they are situated in the middle between the faculty and the air.
Aristotle’s Politics was not available to Ibn Rushd, and so instead he wrote a commentary on Plato’s Republic to express his ideas on political science. This is to some extent a paraphrase of the Republic, while at the same time it quotes Plato on a number of topics and analyses some of his arguments. One particularly interesting passage gives Ibn Rushd’s views on law, prophecy and philosophy. ‘What the laws existing in this time of ours assert...is [that the end of man is doing] what God, may he be exalted, wills, but that the only way of knowing this matter of what it is God wills of them is prophecy.’
Ibn Rushd’s major work on medicine is his al-Kulliyyat (Generalities), which is based mainly on the writings of Ibn Sina, with occasional references to Hippocrates. It is divided into seven books, entitled ‘Anatomy of Organs’, ‘Health’, ‘Sickness’, ‘Symptoms’, ‘Drugs and Foods’, ‘Hygiene’ and ‘Therapy’. Two Hebrew translations of al-Kulliyyat are known, the translator of one of them identified as Solomon ben Abraham ben David. A Latin translation, entitled Colliget, was made in Padua in 1255 by a Jewish scholar named Bonacosa, the first printed edition of which was published at Venice in 1482. A passage in the Colliget gives Ibn Rushd’s explanation of the visual process, particularly concerning what David C. Lindberg describes as ‘the reception of forms in the eye and their subsequent transmission to the seat of consciousness in the brain’. As Ibn Rushd writes in this passage:
And you know that the sense of light receives the forms of things in this manner. First air, when light mediates, receives the forms of things and transmits them to the anterior tunic [the cornea], which conveys them to the other tunics until this motion reaches the final tunic [the retina], behind which is situated the common sense, which apprehends the forms.
Ibn Rushd’s al-Kulliyyat and Ibn Zuhr’s al-Taysir (An Aid to Therapy and Regimen), were meant to constitute a comprehensive medical textbook, and some Latin editions contain both treatises bound together as a single book, which in some places supplanted Ibn Sina’s Canon.
Ibn Rushd wrote a commentary on Ibn Sina’s Poem on Medicine, which was translated into Hebrew prose by Moses ben Tibbon in 1260. The following year a rendering into Hebrew verse was completed by Solomon ben Ayyub ben Joseph. A Latin translation was done in the early 1280s, and a printed edition was published at Venice in 1484. Ibn Rushd also wrote a Treatise on Theriac (Antidote to Poisons), which was translated into Latin by Andrea Alpago, who also did a revised Latin translation of his commentary on Ibn Sina’s Poem on Medicine.
Ibn Rushd also complained about discrimination against women, which he felt was one of the most serious problems in Muslim society. ‘Our society allows no scope for the development of women’s talents. They seem to be destined exclusively to childbirth and the care of children, and this state of servility has destroyed their capacity for larger matters. It is thus that we see no women endowed with moral virtues, they live their lives like vegetables, devoting themselves to their husbands. From this stems the misery that pervades our cities, for women outnumber men by more than double and cannot procure the necessities of life by their own labors.’
Ibn Rushd’s writings deeply influenced Maimonides and through him other Jewish scholars, who read his works in Arabic. By the beginning of the thirteenth century Ibn Rushd was considered to be the outstanding interpreter of Aristotle and his works were translated into Hebrew. By the end of that century nearly half of his commentaries on Aristotle had been translated from Arabic into Latin, so that in the West Averroës came to be known as the Commentator.