The controversy between Islam and Christianity in Arabic is borne witness to in all the areas of interaction between Arab-Islamic culture and Arab-Christian culture, for example Andalusian Spain, a fertile context which left us among other things the well-known Letter of the Monk of France to Muqtadir bi-llâh the Governor of Saragozza, together with the Reply provided on his behalf by the theologian and man of letters Abû al-Walîd al-Bâjî (died 1081). But it had as its chosen place, Baghdad, the capital of the Abbasid empire. The follows of Christ who at that time lived in Islamic territories provided numerous services to the rulers and the powerful in the cultural field: experts in the sciences and often physicians, they had, for example, an important role in many of the centres of culture that were supported by the caliphs, such as the famous House of Wisdom of Baghdad which, together with other similar institutions, contributed to the movement of translations from ancient Greek, at times through Syriac, the liturgical language of the Nestorian faith. This helps to explain their relative safety in the controversy. Great Christian apologists such as Abû Qurra, Abû Râ'ita al-Takrîtî, Hunayn ibn Ishâq, Yahyâ ibn 'Adî, 'Abd al-Masîh al-Kindî, Severus ibn al-Muqaffa' and later Iliyyâ al-Nâsîbî, Yahyâ al-Takrîtî or Paul, Bishop of Antioch, were immersed in apologetics and measured up to the other religion. They had as their interlocutors Muslim scholars of the calibre of al-Jâhiz, al-Kindî, Muhammad ibn Zakariyyâ al-Râzî, al-Ash'arî, al-Bâqillânî, al-Juwaynî, al-Bîrûnî, al-Ma'arrî, Ibn Hazm, al-Ghazâlî and al-Shahrastânî. The works of these and other authors makes it difficult to underestimate the contribution of the Islamic-Christian debate in the reflection and self-definition that here developed by the two great monotheistic religions during this stage of history.
Amongst the leading questions of medieval Christian apologetics in Arabic are to be found, obviously enough, the defence of the divinity of Jesus, of the Incarnation and of the Cross, articles that were incompatible with the Uniqueness and Transcendence advanced by the Koran. One may think here of the Sura of Uniqueness, also known as the Sura of Sincere Religion or the Eternal Koran 112), when it reads 'Say: 'He is God, One, God, the Everlasting Refuge, who has not begotten, and has not been begotten, and equal to Him is not any one', a declaration that was received as a radical sentence that precluded any possibility of mediation with those who professed the presence of God in the man Jesus and, from an Islamic point of view, stained the Almighty with generation and corruption. The Trinity itself was always understood by Muslims as Tritheism, and thus a form of polytheism, forcing Christians to engage in a careful reflection to define the mystery of hypostasis in Arabic. Amongst the questions that involved clashes were still to be found those customs such as chastity and celibacy which in the thought of the Koran and Islam amounted to a blasphemous rejection of the munificence of the Lord, and the institution of penitence which on the Islamic side could only be translated into an impious attempt to take the place of God in relation to the prize or punishment of future life. On the Muslim side there was the question of defending Arab Revelation as the precise Word of God, a gift and an inimitable miracle and not the word of the man Mohammed, together with the moral virtues of the Prophet himself, from Christian attacks. In addition, there was the need to indicate in the holy writ of their antagonists those passages which seemed to allude to the arrival of Mohammed, after a certain fashion a re-edition of the Old Testament foretelling of Jesus. One may think here, for example, of the Islamic doctrine of the Paraclete, which identifies the Consoler (Paràcletos) announced by Jesus in Jn 14:26 with the Famous One or the One Most Worthy of Praise (Periclutòs) who in Arabic is Ahmad or Mohammed. This was an ancient belief that was already to be found in the Koran, in the Sura of the Ranks [ibidem 61:6]. Here Jesus addresses the Jews and says 'Children of Israel, I am indeed the Messenger of God to you, confirming the Torah that is before me, and giving good tidings of a Messenger who shall come after me, whose name shall be Ahmad'. The Muslim apologists had no doubts on the matter. Christian scripture contained human interpolations which undermined their truthfulness at a fundamental level. This is the doctrine that the writers of the gospels engaged in an alteration (tahrîf) of the original texts, a doctrine whose principles the Christians assimilated and which they used against the Muslims, with the accusation that there were examples of incongruence in the Koranic Vulgate such as the full Arabic declared by the Book and the contemporary presence of non-Arabic terms that were unknown to the hearer of that Revelation.
Whether Christians or Muslims, the medieval polemicists knew not only about the dogmas, the rites and the religious ethics of their opponents they knew above all their books. Precisely because they were a codified and solid element, the scriptures lent themselves to debate and were the point of departure for every attempt at a mutual agreement or, to put the point better, at the level of fact, of every proselytising appeal, given that each participant perceived exclusively in his own religion the common benefit that was to be found in shared knowledge of the True. Although the Koran was comprehensible in Arabic for Christians, the Christian scriptures were known for the most part in translation through the various versions in Arabic of the Bible, and these are to be dated at least to the beginning of the ninth century, although with all probability they were much older.
Let us take as an example of the early stages the correspondence, which was very probably written under the caliphate of al-Ma'mûn and thus between 813 and 833, between the Muslim 'Abd Allâh al-Hâshimî and the Christian 'Abd al-Masîh al-Kindî (who is not to be confused with the other famous al-Kindî, the Muslim and Helenising philosopher)2. This correspondence became known about in Europe in the first half of the twelfth century in a Latin translation with the title Epistola Sarraceni ad suam sectam Cristiani invitantis, a work commissioned by the Abbot of Cluny, Peter the Venerable, and carried out by Peter of Toledo and then included in the famous Collectio Toledana. Invited to conversion by his interlocutor, 'Abd al-Masîh attacks Islam in clear terms by declaring that it is a false religion and condemning it on the basis of the scriptures, the inconsistency of the Koran and the non-existence of its miraculous character. He also criticises Muslim law in harsh terms, above all its institution of marriage and prohibitions as regards diet, as well as the pilgrimage to Mecca which he ridicules as a set of bizarre rites. Of interest as well is his digression on the Jihâd, which he declares cannot be likened to the martyrdom of Christians. Behind the polemical vein and the very harsh emphases, which helped to channel that strongly detracting image of Islam specific to our medieval period, this small work nonetheless expresses a secure knowledge of the two faiths by both authors.
Another eminent example of knowledge of the sacred scriptures of the other religion, which came later and this time is on the Islamic side, is the section that Ibn Hazm di Cordova (died 1012) dedicates to Christianity in his Book on Distinction in Religions, Heresies and Sects. Its author demolishes the entire Christian Christology and puts under a harsh microscope, taking the Gospels chapter by chapter, chronological, genealogical and geographical examples of negligence and contradictory phrases. In this last field he stresses the incongruence that he detects between the phrases 'son of God' and 'son of Man' that were variously applied to Jesus and between the divine Sonship at times limited to Jesus and at times extended to all Christians, as in the invocation of Our Father in the first chapters of the first Gospel.
A major characteristic of the debate between Islam and Christianity of the classic age was that it wanted from the outset to be based on reason. The anonymous Rational and Religious Questions and Answers between a Muslim notable of Jerusalem and a monk, which can be dated to the end of the seventh century and which is based upon rational argument as well as on citations from the Bible and the Koran, has an instructive title. And very soon a dialogue was conducted according to the criteria of Aristotelian logic. A translation into Arabic of First Analytics, the books of the Organon that studied the syllogistic structure of coherent and formally valid reasoning, is to be dated to little after the middle of the ninth century. Complete editions of this work were produced in Baghdad in the tenth century thanks to Ishâq ibn Hunayn and then a Yahyâ ibn 'Adî. In the Islamic world, as in the West, religious authorities never really called into question the importance of the Organon. Amongst Muslims, not only the Hellenising philosophers but also theologians and jurists including, by no means rarely, those of a traditionalist approach appealed more or less openly to Aristotelian methodology. We should remember amongst others al-Ash'arî (died 935), a founder of Islamic orthodoxy, who skilfully used the art of logic in his writings, as indeed did the great al-Ghazâlî (died 1111), the 'Thomas of Islam', who, however, did so even more. Although he feared the snares of the discipline in question, al-Ghazâlî declared that it was scales of knowledge and a servant of truth, and laid emphasis on the precedents to be found in the Koran. His lapidary contestation of the divinity of Jesus is famous, which he effected through a syllogism in which he summarises the absurdity of the Christian position: Christ was crucified3, a divinity cannot be crucified, therefore Christ is not a divinity. This is what is to be read in the Complete Refutation of the Divinity of Jesus, which, indeed, is attributed to him.
Fakhr al-Dîn al-Râzî (died 1209) made ample use of Aristotelian categories and he called his readers to the science of logic and the theory of knowledge in his introduction to his famous Summary of the Opinions of the Ancients and Posteriors. This eminent theologian would later, amongst other things, engage in a disputation with an anonymous Christian scholar4, the foundation of which is the strong plausibility of the proof that alone can provide validity to what one intends to affirm by its use. This disputation looks in particular at the discordant attributions as regards status that the two religions attribute to their respective founders (the prophecy of Mohammed and the divinity of Jesus), at a number of erroneous Christian beliefs about Islam (for example the spread of religion by the sword), and other less explored questions such as the excellence of burial in the ground, which was granted to Mohammed, as against ascension to heaven which the Muslim faith also attributes to Jesus: paying attention to the good of the community, observes al-Râzî, the burial in the ground that God gave to Mohammed was undoubtedly better because it discourages believers from divinising their prophet, an error in which, in contrary fashion, Christians had fallen. In this small work, the two parts are continually in front of each other, each one with its own questions and answers, and what is most interesting is that each one is directed towards going to the basis of the dogmas of the other to arrive at a full rational understanding of basic affirmations. To give an example of the discussion, the Christian scholar perorates the divine and not merely prophetic rank of Jesus, the Muslim asks to begin again from the definition of divinity, observes that it is separate from corporeity and spatial and temporal belonging, and opposes the Christian with the paradox of a God Christ who is born in a place and was killed in a place, who was a new-born child, an infant and then an adult, when what is new cannot be old or what changes cannot be stable, on the basis of the shared principle of non-contradiction. On the basis of this same principle, the Christian answers that Jesus was truly and without doubt human but then in turn he refers the Muslim to statements that he cannot oppose, namely that the Creator of the world, who has no modalities or equals, certainly has the ability to take any form that He wants, which would not of necessity be identical to Him. And while he confirms to his adversary the debate on this subject amongst his own Christian brothers, he reminds him of the analogous debate on the corporeity of God amongst Muslims, as well as of the divine inhabitation claimed by some Islamic mystics. To this argument the Muslim objects that once the presence of God in the body of Christ is admitted, there is no rational certainty that the same event has not befallen others men, animals, plants or even inanimate beings.
A correspondence that is rather well known wants to use syllogism without halting, namely that between Ibn al-Munajjim, who belonged to an important Mazdean family that converted to Islam, and Qustâ ibn Lûqâ, a Melechite Christian who was born in the Lebanon, lived in Baghdad and died in Armenia in about 912, a translator and reviser of previous translations. Ibn al-Munajjim begins his Epistola, which he defines as a demonstration, warning that every premise is a universally accepted assumption in conformity with original nature, and that therefore every conclusion is incontestable for those who are rational in their approach. The acceptance of his analysis, he observes, can only involve the conversion of the Christian to Islam. The author provides certain logical arguments intended to prove the truthfulness of the Prophet Mohammed and the miraculous character of the Arab Book. Amongst these arguments may be found the following: only God, the Creator, has knowledge of Mystery; Mohammed, even though he was a created human, also had knowledge of it in that he challenged the Arabs to imitate the formal and sapiential perfection of the Koran well knowing that they would not have done this; thus he must have learned from God such knowledge of Mystery, and this involves him having the status of a prophet. Qustâ ibn Lûqâ objects that Mohammed, as an intelligent and judicious man, which he was, had to launch his challenge to imitate the Book because he was certain of his own very human capacities and only did so after a careful assessment of the likelihood of success. And to the inimitability of the Koran, which is equivalent in Islamic thought to the miraculous nature that confirms its divine origins, he applies the logical principle of the convertibility of terms: it may be said that a miracle is an inimitable act only and solely if every inimitable act can be said to be a miracle; he then refers to certain human works the pyramids of Egypt, the lighthouse of Alexandria, daily works of admirable workmanship or the works of Homer which because of their greatness or beauty or brilliance are in effect unrepeatable in other forms, without this involving a mission from God or a prophetic role being attributed to their authors. The Christian calls into question the same knowledge of Mystery as a prerogative of God and His gift to creatures and opposes to it a definition which is totally secularised: Mystery is what escapes the immediate perception of the senses, such as an illness which hides in a body but which an able physician is able to identify, or an arriving storm which cannot be seen by the eye but which a good sailor can foresee. What the Christian asks from his interlocutor is thought free from influences imposed by the Koran: in the case of the Unseen, he asks Ibn al Munajjim to depart from the definitions that the Book gives of it when it states that 'The Unseen belongs only to God' [Koran 10:20], that 'None knows the Unseen in the heavens and earth except God' [27:65] or that 'with him are the key of the Unseen' [6:59]; in the case of the miraculous nature of the Koran provided by its inimitability, he asks him to forget that the Koran says that it is in itself inimitable [cf. for example 2:23-24, 10:38-39 and 17:88], and that the definition of a miracle as an inimitable act and proof of the truthfulness of a prophet rests on the inimitability of divine work and in the first instance on the declared inimitability of His revealed Word. The Risposta of Qustâ ibn Lûqâ to the Epistola of Ibn al-Munajjim certainly marks a notable moment, not so much in the history of inter-religious dialogue as in the history of human thought: in basic terms it is an appeal to pure and simple reasonableness and to the abandonment of confessional analysis, whose significance and possible consequences perhaps escaped the author himself.
[This article is taken from I. Zilio-Grandi, 'Le opere di controversia islamo-cristiana nella formazione di una letteratura filosofica araba', in C. D'Ancona (ed.), Storia della filosofia nell'Islam medievale (Einaudi, Turin, 2005) vol. I, pp. 101-136 and from Una corrispondenza islamo-cristiana sull'origine divina dell'Islam (translation, introduction and notes by I. Zilio-Grandi, Arabic text by S. Khalil Samir), Patrimonio Culturale Arabo Cristiano (PCAC) 8 (Silvio Zamorani Editore, Turin, 2004. Translator's note: all quotations from the Koran are from the A.J. Arberry translation]
1. English translations of the Qur'a_n are taken from A. J. Arberry, The Koran Interpreted (London, 1955).
2. Cf. Al-Kindi, Apologia del Cristianesimo (translation, introduction and notes by L. Bottini), Patrimonio Culturale Arabo Cristiano (PCAC) 3, (Zamorani, Turin, 1998).
3. As is known, Islamic doctrine denies the crucifixion of Jesus but concedes his ascension, starting with the Koran 4:157-159.
4. The authenticity of which has been confired by its Lebanese publisher.
Cf. also for what follows: Fakhr AlDîn Al-Râzî, Munâzara fi al-radd 'alâ al-nasâra (edited by 'Abd Al-Majîd Al-Najjâr), (Dâr al-Gharb, Beirut, 1986.