CHAPTER 1

HISTORICAL SURVEY


1.1 The foundations of Islamic thought
      1.1.1 At the time of the Medinan caliphs
      1.1.2 The Umayyad period
      1.1.3 The `Abbsid period (750-)
1.2 The philosophical movement in the land of Islam
1.3 Conflict between philosophers, Ash`arites, Mu`tazilites, and Hanbalites
1.4 The principal philosophers
      Al-Kind (c. 800-866)
      Ar-Rz (c. 865-925 or 932)
      Ibn-Masarra (883-931)
      Isq ibn-Sulaymn Isrl (c. 855-955)
      Al-Frb (875-950)
      Miskawayh (932-1030)
      Ibn-Sn (980-1037)
      Ibn-Gabirol (c. 1021-1058)
      Al-Ghazl, a theologian opposed to philosophy (1058-1111)
      Ibn-Bjja (?-1138)
      Ibn-Tufayl (1105?-1186)
      Ibn-Rushd (1126-1198)
      Moshe ben Maimon
1.5 The influence of these thinkers in Christian Europe
1.6 Later developments


1.1 The foundations of Islamic thought

1.1.1 At the time of the Medinan caliphs[1]

When Muhammad died he left no instructions for his succession. At an emergency meeting convened to decide what to do, the senior men were divided until `Umar got up and clasped the hands of Ab-Bakr; the rest followed suite. The choice was a compromise, since Ab-Bakr (632-634) was an old man.

Ab-Bakrs first job was to send his general, Khlid ibn-al-Wald, against the Arab nomads to force them to accept his authority. Once the Arabs were united as one umma, since Muslims may not fight Muslims, their armies turned to lands of the north. These were exhausted by a protracted struggle between the Byzantine and Persian empires, the super-powers of the time, and the Arabs easily overran them.

During the caliphate of `Umar (634-644) the Muslim umma experience a real booty boom. The Arab soldiers were inspired by a strong faith that assured them of a heavenly reward if they died in battle, and an earthly reward if they did not. As these men sent back to Medina the fortunes they had gathered, other men of lesser faith now rushed to join the army. But they found little pickings left in Syria, Palestine, Egypt, Iraq and the whole Persian empire.

Boom times had become doom times, and the blame was laid at the feet of the new caliph, `Uthmn (644-656). Mutinous troops demanded his resignation. He refused and they stabbed him to death, installing `Al (656-661) in his place.

Mu`wiya, the governor of Damascus and a relative of `Uthmn, refused to recognize `Al, and a civil war broke out. Various battles and negotiations took place, and in the end Mu`wiya won out, founding the Umayyad dynasty, which lasted almost a century.

1.1.2 The Umayyad period

During the lifetime of Muhammad a radical change of attitude took place in the Arab world. Everyone, including opponents of Islamic rule, found themselves incapable of thinking or of expressing themselves in other than Qurnic categories.[2]

During the caliphate of Ab-Bakr some apostates presented themselves as rival prophets, with revelations patterned after the Qurn. During the Umayyad period, however, any rebel had to claim that he was a better Muslim than his adversary.

This transformation of the public mentality was not the result of interior conversion involving intellectual conviction and change of life. We have to distinguish conversion from joining a movement. The vast majority of new Muslims joined Islam because it was a winning movement launched by a man who had full confidence in his authority and mission as the last prophet. You are the best community raised up among men; you command what is good and forbid what is evil and believe in God. If those who have Scripture had believed it would have been better for them... (Qurn 3:110).

It became impossible to escape Qurnic ideology, which was the orthodoxy of the society, since membership in that society was a necessity for survival. Qurnic rules of living, however, were simple, practical and adaptable to the still evolving condition of Islam at that time, and provided a rallying point for a society in transition.

1.1.3 The `Abbsid period (750-)

Throughout the Umayyad period the Muslim community, by force of circumstances, adopted a vast amount of new regulative norms not contained in the Qurn. These became enshrined in tradition, or Hadth literature, which claimed the authority of the companions of Muhammad and eventually the authority of Muhammad himself. Under the influence of ash-Shfi` (d. 825), Hadth became another source of revelation alongside the Qurn. As ash-Shfi` put it, Muhammad, the seal of the prophets was divinely ordained as the perfect man, impeccable, infallible, the model and exemplar for all mankind. Although Hadth was not dictated by God like the Qurn, all the actions and words that they relate are taken as another form of revelation.[3]

How, we must now ask, could a philosophical movement flourish in a milieu so dominated by Islamic religious thought?

1.2 The philosophical movement in the land of Islam

The philosophical movement caught on the Muslims by contact with Greek philosophy which their Christian subjects cultivated in Egypt, Syria and Iraq. There was also some Jewish influence with regard to the method of qiys, or analogical reasoning in law.

The Fathers of the early Church took an interest in philosophy when they came into contact with the Greek community of Alexandria, which had an old and well established school of philosophy. The Greeks of Alexandria embraced Christianity in the second century, as Christian apologetes presented Christ to them as Wisdom incarnate.

Since the native Egyptian Copts were not well represented in this school, it closed when the Arabs conquered Egypt and the Greek elite left Egypt. Around 718 the school was re-established at Antioch in Syria and later moved to Iraq. Teaching was conducted in the Syriac (= Aramaic) language. At Gondeshapur, in Iraq, the major works of Greek philosophy were translated into Syriac and many original works were composed. By and large, neo-Platonism dominated the thought of this school.

When the Arabs conquered these Christian territories, they mostly avoided the schools and educational system that was there because they mistrusted anything that was not Arab. Their attitude was that it was either anti-Islamic or useless, since everything worth knowing is contained in the Qurn. In spite of this general attitude, a few Muslims took an interest in philosophy, for the following reasons:

1) At times Muslims engaged in debates with Christians and found themselves on the defensive when the Christians used philosophical arguments to defend their positions. These Muslims then decided to learn philosophy so as to have better answers to the Christians.

2) The caliphs and other influential Muslims were interested in philosophy for its practical advantages. Philosophy, we must remember, was a single package that included all the human sciences: astronomy, mathematics, medicine and technology, as well as metaphysics.

3) The caliphs also had a political reason for supporting the philosophers. That was because the philosophers, along with the Persian civil servants, did not share the Arabs disdain for all that was not Arabic or Islamic. They were a convenient support for the caliph when he did not want to be hemmed in by religious scholars insisting on their narrow interpretation of Shar`a.

The caliph al-Ma`mn (1813-833) then established at Baghdad the Bayt al-hikma (House of Wisdom), a center dedicated to translation of philosophical works into Arabic and original research. Muslim and non-Muslim scholars freely mixed in this institute, and Iraq became the intellectual center of the Muslim world.

Some of the better know translators of philosophical works from Greek to Arabic were Qus ibn-Lq (m.c. 913), Hunayn ibn-Ishq (808-873), his son Ishq ibn-Hunayn (m. 910), his nephew Hubaysh, and Ab-Bishr Matt (d. 940). As these names indicate, the work of translation was largely a Christian affair. These men were not only translators, but also wrote important original works of their own.

Which new branches of learning were thereby introduced to the Muslim world? According to al-Frb [4] or Ibn-Sn,[5] they included:

(1) logic, following Aristotles treatises on reasoning along with rhetoric and poetry,

(2) mathematics, with physical applications such as music and astronomy,

(3) natural science in all its branches, particularly the study of man and the practical science of medicine,

(4) the moral sciences such as ethics and politics,

(5) and finally metaphysics or natural theology.

1.3 Conflict between philosophers, Ash`arites, Mu`tazilites, and Hanbalites

Al-Mamn favored the Mu`tazilites theological school which defended certain positions by means of philosophical methods which the Hanbalites opposed, because they disregarded a literal interpretation of the Qurn. For example, the Mu`tazilites taught the freedom of human choice as opposed to divine predetermination, and the absolute unity of God and all his attributes, except for his word, the Qurn, which they held was created -thereby countering Christian teaching on the Logos and a foundation of Ash`arite determinism.

The scholar and Tradition master, Ahmad ibn-Hanbal, was persecuted by the `Abbsids for refusing to subscribe to the Mu`tazilite thesis that the Qurn was created. But his popular following in Baghdad reacted, and in 849 their hostility forced the caliph al-Mutawakkil to expel the Mu`tazilites and philosophers from his court. Both groups, however, continued to study and write elsewhere.[6]

The more traditional Ash`arite school took their place. Named after Ab-l-Hasan al-Ash`ar, an ex-Mu`tazilite, this school continued to use the rational methods and philosophical concepts of the Mu`tazilites, but the theses they defended were traditional and conservative. In spite of that, Ibn-Hanbal and his followers opposed al-Ash`ar, rejecting all rational or philosophical discussion and insisting on the Qurn and Tradition alone.

Although philosophy and rational theology both flourished after 849, each went its own way without mutual influence until the time of al-Ghazl. Theologians continued to use the philosophical concepts introduced into theology before 849, and the philosophers developed teachings that sometimes contradicted Islamic faith.

In the meantime, Spain, never subject to the `Abbsids, continued to harbor philosophers for some time, especially under Umayyad rule. After this dynasty declined, Spain broke up into small principalities until the Murbit conquest in 1090. The Murbits encouraged the study of Mlik law and, like the Hanbalites, banished systematic theology (kalm). Yet they tolerated philosophy, maybe because the philosophers were more cautious and did not publicize their opinions.

The Muwahhids overthrew Murbit power in 1147 and introduced kalm, with the works of al-Ghazl. The Muwahhids were intolerant, especially of Christians, but the prince Ab-Ya`qb (1163-84) was interested in philosophy, even though he dared not show it publicly. Among his friends were Ibn-Bjja and Ibn-Tufayl.

1.4 The principal philosophers[7]

Al-Kind (c. 800-866)

During the regime of al-Ma`mn, the political and intellectual climate permitted the rise of the first philosopher of Arab blood, al-Kind. He had a large library and mastered all the Greek sciences he could come across. Yet he was far from the free thinking of later philosophers, holding firmly to the dogmas of Islamic faith, although he thought that neo-Platonic thought was harmonized with it, with some corrections, such as creation from nothing instead of natural emanation, the need for prophecy and the possibility of miracles. Al-Kind influenced the Mu`tazilites, the first philosophical theologians.

We have at least fifty-three works of al-Kind. As an Arab writer, he had a very beautiful and clear style which can be read without much difficulty.

Ar-Rz (c. 865-925 or 932)

Muhammad ar-Rz lived in the difficult period following al-Kind. He was most famous as a medical doctor, but also wrote on ethics and metaphysics. For him philosophy took the place of religion. He thought that a philosopher should keep out of politics and devote himself to contemplative and scientific activity. We will see later how he deviated from Islam on several points. Yet we must keep in mind that the works where he expresses these ideas are lost, and we only have descriptions of his positions written by his critics.

Ibn-Masarra (883-931)

Born in Cordoba, he had to take refuge in the mountains because of persecution by Mlik jurists. His works present neoplatonic ideas in the form of a highly allegorical exegesis of the Qurn. Only two short treatises of his have survived.

Isq ibn-Sulaymn Isrl (c. 855-955)

Known in medieval Europe as Isaac ben Solomon Israeli (c. 855-955, born in Egypt, wrote in Qayrawn), Isq ibn-Sulaymn was most famous for his medical works. He is also considered the father of Jewish Neoplatonism. Of his few known works, his Kitb al-hudd wa-r-rusm was known in Europe as Liber de definitionibus.

Al-Frb (875-950)

Living in the `Abbsid heartlands, Al-Frb (Alfarabius), the real founder of Arab neo-Platonism, held everything emanates from God in a hierarchical order. Thus he theorized about a heavenly hierarchy of spirits and an earthly hierarchy led by a philosopher-king. In the context of the time of al-Frb, this could mean a Sh`ite imm.

At least sixty-three authentic works of his are known. Most of these are published. Some works attributed to him really belong to Ibn-Sn. Although he was not an Arab, his style is very clear and simple.

Miskawayh (932-1030)

Miskawayh was an important predecessor of Ibn-Sn. Very little is known of his life, except that he worked in the service of the Byids. His writing are mainly about ethics, but he also touches on some important theoretical questions.[8]

Ibn-Sn (980-1037)

Ibn-Sn, known in Latin Europe as Avicenna, was the greatest representative of Arab neo-Platonism. Of Persian or maybe Turkish stock, he studied all existing branches of learning and was particularly renowned in medicine. He read Aristotles Metaphysics forty times without being able to understand it until he came across a commentary of al-Frb.[9] Having mastered all these sciences by the age of 18, he said that his knowledge continued to mature but he learned nothing new.

His father tried to get him to accept Sh`ism, but he refused. For this reason we see little speculation in his works about the earthly hierarchy. Ibn-Sn served as a medical doctor to various princes that ruled fragments of the caliphate. He spent his nights writing or teaching, but when he got tired he drank wine or indulged in sex. The latter addiction is said to have accelerated his death.

George Anawati,[10] following manuscript catalogues, lists 276 titles attributed to Ibn-Sna, many of which are duplications or doubtful; Yahy Mahdavi[11] reduced them to 132. Cataloguing the works of Ibn-Sn is complicated because of erroneous attribution of some of his works to Al-Frb and of some of his students works to himself, and because parts of some of his works were re-published under another title, sometimes mixed with other material.

More than one hundred and ninety works of Ibn-Sn have been published, many of them small treatises. Noteworthy are his great Qnn f t-tibb, on medicine, and the monumental Shif, a suuma of all branches of philosophy. Yet in his small works he often expresses himself more openly on controversial questions. Ibn-Sns style is rather simple, but often unclear, with pronouns having no definite antecedent and unexplained changes of person or gender. Nevertheless the context brings out the meaning of such passages. Once Ibn-Sn was accused of having a bad knowledge of Arabic; this led him to a deep study of the language and afterwards he wrote a few tracts in a very elaborate and difficult style.

Ibn-Sn had to endure some opposition during his life, which he complains of in his Risla f l-intif `am-m nusib ilay-hi (without mentioning the accusations made against him) and in Risla il `Aladdn ibn-Kkawiyya, where he complains that his patron abandoned him.

Ibn-Gabirol (c. 1021-1058)

A Spanish Jewish philosopher, Ibn-Gabirol (Avicebron/Avicebrol) is known mainly for his Fountain of life, written originally in Arabic, but suviving only in Hebrew and Latin translations. In it he develops neoplatonic thought, yet without transgressing Jewish dogma.

Al-Ghazl, a theologian opposed to philosophy (1058-1111)

The chief opponent of the philosophers was al-Ghazl (Algazel). At an early age he was initiated into Sfism and mastered the study of theology and law. In 1091 he was appointed professor at the Nizmiyya college in Baghdad, where he became famous. Meanwhile he read the works of al-Frb and Ibn-Sn. This study resulted in two works: Maqsid al-falsifa, a summary of the principal teachings of these philosophers, and Tahfut al-falsifa (Incoherence of the philosophers), a polemic attack on these teachings. Only the first of these works was known in medieval Europe under the title of Metaphysica.

Then, as a result of psychological tensions and fear of Hell fire, he had a nervous breakdown affecting his ability to talk; so he had to abandon his teaching. He retired to the life of a Sf, where he regained his peace and health, and soon attracted a group of friends around him. In 1106, at the beginning of the 16th Islamic century, these friends proclaimed him the mujaddid or renewer of religion who, according to some traditions, was expected at the beginning of every century. Persuaded to return to his teaching, he resumed writing and composed his major work, Ihy `ulm ad-dn (Revival of religious sciences).

Al-Ghazls previous study of philosophy resulted in the absorption of many new concepts into theology, especially a good dose of Aristotelian syllogistic logic. This meant an enrichment of systematic theology or kalm, but his attacks on philosophy led to the near total eclipse of philosophy as an independent study, at least in the Muslim East.

Ibn-Bjja (?-1138)

Ab-Bakr Muhammad ibn-Yahy ibn-as-Sigh, known as Ibn-Bjja (Avempace), was born towards the end of the 11th century. He wrote some good commentaries on Aristotle, but is known more from his works on ethics, where he also discuss the human soul and intellect. After complaining about the quality of philosophy in Spain before the introduction of logic, Ibn-Tufayl says of him:

Among recent thinkers, there is no one sharper, more penetrating and more true in his thinking than Ab-Bakr ibn-as-Sigh, except for the fact that he was engaged in worldly affairs to the day of his death and could not show the treasures of his knowledge or publish the secrets of his wisdom. Most of his writings were not completed.[12]

Ibn-Tufayl (1105?-1186)

Ibn-Tufayl left us a single work, the novel Hayy ibn-Yaqzn, about a lost child brought up on an island by a gazelle. He shows how Hayy mastered all sciences, came to a knowledge of God and a direct experience of him. This work, with an esoteric, philosophical-sfic slant, also discusses other important questions.

Ibn-Rushd (1126-1198)

The great Ibn-Rushd (Averroes), already renowned as a medical doctor, was introduced to the Muwahhid emir, Ab-Ya`qb, by Ibn-Tufayl. When the prince asked him his opinion on the eternity of the world, Ibn-Rushd shook, but the prince calmed him down and encouraged him to speak freely. Afterwards the prince gave him some money, a robe and a horse, asking him to continue his studies and to make an understandable summary of the works of Aristotle.

Ibn-Rushd set about this immense task, and wrote commentaries of three different sizes on almost every book of Aristotle. Ibn-Rushd began with the small commentaries, which are summaries of the thought of al-Frb. Then he did the medium ones to synthesize the most important points Aristotle was making.[13]

Towards 1178, since he was much disturbed by the growing anti-philosophical influence of al-Ghazl in Spain, Ibn-Rushd wrote ad-damma and Fasl al-maql on the relationship between philosophy and revelation. Then came his al-Kash `an manhij al-adilla f `aqid al-milla, and a long refutation of al-Ghazls Tahfut al-falsifa, his own called Tahfut at-Tahfut (Incoherence of the Incoherence).

After these apologetic works, Ibn-Rushd began his large commentaries on Aristotle, and lastly made revisions of his small and middle commentaries, often in the form of separate little treatises (maqlt). Then he turned his attention to medicine, and wrote commentaries on Galens to correct them in the light of his own physical theory.

Ab-Ya`qb, however, could not suppress the strong opposition to philosophy coming from the Mlik jurists, and after his death, from 1195, Ab-Ysuf Ya`qb al-Mansr, persecuted the philosophers and ordered the books of Ibn-Rushd and other philosophers to be burned. Banished from Cordoba, Ibn-Rushd finished his commentary on The generation of animals in 1198. The same year he died in Morocco.

About 104 works of Ibn-Rushd are known. Most of his important commentaries on Aristotle, except that on the Metaphysics, are lost in Arabic, having been burned by his enemies, but they are preserved in Latin or Hebrew translation, thanks to the Jewish and European fascination with his thought at the beginning of the 13th century.

Moshe ben Maimon[14]

Moshe ben Maimon, better known as Maimonides, was born at Cordoba in 1138. Because of the Muwahhid conquest of Spain, he had to flee to Fez in 1160. There he wrote his Letter of consolation for Jews forced to accept Islam, showing them how to pray and do good deeds while remaining Jews in secret. In 1165 he fled to Acre, in Syria, and five months later to Fustt, next to Cairo. In 1171 he became the leader of the Jews in Egypt. He held this post for five years; twenty years later he held this post again until his death in 1204. He served as a medical doctor to al-Fadl, the wazr of Salhaddn, but was especially known as a jurist in Jewish law. He wrote his Mishna Tora in 1180 and the famous Dalil al-hirn (Guide of the wandering) in 1190.

He wrote all his works in Arabic and they were later translated into Hebrew and other languages. An admirer of al-Frb, Ibn-Bajja and Ibn-Rushd, he concealed his ideas as they did for political reasons and to avoid disturbing the faith of simple people.

His philosophical teaching is of interest particularly with regard to the nature and destiny of the human soul. This will be discussed in Chapter 4.

1.5 The influence of these thinkers in Christian Europe[15]

Through Spanish translators, Ibn-Rushd, like Ibn-Sn, had an enormous influence on European thought. The scientific works of Aristotle were first translated into Latin at the beginning of the 13th century: the Nicomachaean Ethics, Metaphysics, Physics, De Caelo, De Anima etc. Seeing these as a subversive of Christian belief, Church authorities forbade the teaching of Aristotles philosophy of nature at the Faculty of Arts at Paris in 1210. This ban was repeated in the University statues of 1215, 1231, 1245 and 1263. But the Faculty of Theology continued to study Aristotle and developed systematic theology which from 1230 became a major field of study alongside the longstanding exegesis of Sacred Scripture.

Meanwhile the Arab commentators of Aristotle, particularly Ibn-Rushd, were translated. This work was done swiftly by Michael Scot in Sicily from 1228 to 1235, but it took a longer time before these works were understood. The heterodoxy of the Commentator was spotted only around the middle of the 13th century. Earlier Philip the Chancellor, William of Auvergne, and Albert the Grand quoted him without noticing any problem.

Bonaventure was the first to criticize Ibn-Rushd, in his Sentences, then Albert the Grand in his De unitate intellectus.

The Pope set up a commission to find out what was valuable in Aristotle and his commentators and eliminate the errors, but it accomplished nothing. The job was then entrusted to Albert the Great and Thomas Aquinas. Thomas Aquinas, in his Summa Contra Gentiles, made the first systematic and in-depth critique of Ibn-Rushd. Then, particularly in his philosophical commentaries, he assimilated the best of Aristotle and laid down permanent principles for the reconciliation of philosophy and theology, or of science and religion.

Meanwhile Ibn-Rushd appeared in a Latin Averroism whose chief leader was Siger de Brabant. He taught at the Faculty of Arts in Paris from 1260 to 1277, but his heterodox teaching on the human intellect was noticed for the first time in 1266. Bonaventure criticized him in 1268, then Albert the Grand in his De quindecim problematibus and Thomas Aquinas in his De unitate intellectus, both in 1270. On 10 December 1270 Etienne Tempier, Archbishop of Paris, condemned some Averroist theses, then on 18 February 1277 enlarged his condemnation and banished the Averroists. Siger de Brabant then fled to the Papal court at Orivetto, where he was assassinated shortly before 1284, by a mad clerk.

1.6 Later developments

The medieval Muslim world failed to accommodate philosophy in its civilization and its philosophers failed to gain acceptance. Philosophy, including scientific and technological research, died as an independent study, and only the debris picked up and absorbed by theology survived, such as logic.

In the East, a mystical philosophical movement developed, under the inspiration of Ibn-Sn. It was known as the illumination (ishrq) school, and was represented especially by Suhraward (m. 1191).[16] There was also the pantheistic existentialism of ash-Shrz (= Mull adr, 1571-1640) and his school of wisdom (hikma).[17] These movements were a continuation of Avicennian Neoplatonisme with a theosophic mixture of Zoroastrianism, Pythagorean numerology, Sfism and some metaphysical notions. They were very far from ancient and modern scientific tradition.[18]

Such was the situation of the Muslim world until contact with Europe in the 19th century stimulated a revival.



[1] Cf. L.V. Vaglieri, The patriarchal and Umayyad caliphates, pp. 57-103.

[2] Cf. W.M. Watt, The majesty that was Islam, p. 58.

[3] Cf. J. Burton, The collection of the Qurn, chs. 2 & 3.

[4] Ihs al-`ulm.

[5] Aqsm al-hikma; Ta`lqt, pp. 169-172

[6] Cf. J. Kenny, Aux sources du radicalisme islamique, 135-140.

[7] For the lives of these philosophers, see M.M. Sharif (ed.), A history of Muslim philosophy;`Abdarrahman Badawi, Histoire de la philosophie en Islam, M. Fakhry, A history of Islamic philosophy, and the articles on each in the Encyclopaedia of Islam.

[8] Cf. Mohammed Arkoun, Deux pitres, introduction.

[9] Maqla f aghr m ba`d at-tab`a.

[10] Muallaft Ibn-Sn.

[11] Fihrist-i musannaft-i Ibn-i Sn.

[12] Hayy ibn-Yaqn, pp. 111-112.

[13] For the chronology ofthe works of Ibn-Rushd, see `Abdarrahmn al-`Alaw, al-Matn ar-Rushd (Dr al-Bay, 1986), and J. Kenny, The chronology of the works of Ibn-Rushd on this site.

[14] Cf. Colette Sirat, La philosophie juive mdivale en terre dIslam, pp. 179-237.

[15] Cf. G. Quadri, La philosophie arabe dans lEurope mdivale; A.-M. Goichon, La philosophie dAvicenne et son influence en Europe mdivale; and especially Zdzislaw Kuksewicz, De Siger de Brabant Jacques de Plaisance, ch. 1.

[16] Cf. Seyyed H. Nasr, The significance of Persian philosophical works in the tradition of Islamic philosophy, p.70.; L. Gardet, A propos de lishrq de Suhrawardi.

[17] Cfr. Toshihiko Izutzu, The concept and reality of existence; Fazlur Rahman, The God-world relationship in Mulla Sadr, pp. 238-259.

[18] Cfr. M. Fakhry, ch.10, qui regarde ces mouvements plus positivement que moi.