Should a Muslim study logic?

1The first objections

Logic entered Arabic with the translations of Greek philosophy, and the first objections came from the grammarians. The TDV İslâm Ansiklopedisi summarises their arguments: logic is a foreign product; native intelligence and practice in debate are enough; and grammar alone can secure correct meaning. The best-known clash was the debate before a vizier between the grammarian Abū Saʿīd al-Sīrāfī and the logician Abū Bishr Mattā (d. 940), in which al-Sīrāfī confounded his opponent with grammatical subtleties.

The logicians answered in two ways. Al-Fārābī argued that grammar gives the rules of one language and logic the rules common to all. Ibn Sīnā argued that natural intelligence can reach right conclusions only by chance, without any guarantee against error. Some writers, among them Abū Sulaymān al-Sijistānī and Abū Ḥayyān al-Tawḥīdī, took a middle line: logic and grammar are two faces of one thing.

A second line of objection was religious. Because logic was taught together with philosophy, its critics saw it as the doorway through which the philosophers’ doctrines on God, the world and the soul entered Muslim thought. Tony Street and Nadja Germann note that some scholars considered the study of logic impious ‘mainly because of its association with metaphysics’. This is the debate this article follows. A shorter account, focused on the commentaries on the Īsāghūjī and the Sullam, is in ‘Scholars on studying logic’.

2Al-Ghazālī: a neutral tool

The decisive defence came from al-Ghazālī (d. 505/1111). He wrote several logic books, among them Miʿyār al-ʿilm (‘the yardstick of knowledge’), Miḥakk al-naẓar (‘the touchstone of reasoning’) and al-Qisṭās al-mustaqīm (‘the straight balance’). In the Miʿyār he argued that reasoning in law does not differ from reasoning in philosophy ‘in its composition, conditions or measures, but only in where it takes its premises from’. At the start of his late work on legal theory, al-Mustaṣfā, he wrote that his introduction on logic is not part of legal theory but ‘an introduction to all the sciences, and he who does not master it is not to be trusted at all in his sciences’.

In his autobiography, al-Munqidh min al-ḍalāl, he separated logic from metaphysics: logic studies the methods of proof and the conditions of definitions, and he asked what this could have to do with the principles of religion, that it should need to be accepted or rejected. Frank Griffel describes al-Ghazālī as the starting point of the ‘naturalisation’ of Avicennan philosophy in Muslim theology, and Ibn Khaldūn later wrote that since al-Ghazālī and Fakhr al-Dīn al-Rāzī scholars had been more lenient towards logic, after an early period in which theologians had forbidden it.

3Ibn al-Ṣalāḥ’s fatwā

A century later the strongest prohibition came from Damascus. The Shāfiʿī hadith scholar Ibn al-Ṣalāḥ (d. 643/1245), head of the Dār al-Ḥadīth al-Ashrafiyya, was asked about people who studied and taught philosophy and logic. According to the TDV he called philosophy absurdity, bewilderment and error, and held that because the Ismāʿīlī Bāṭinīs used philosophy and logic against the Sunnis, it was the ruler’s duty to protect Muslims from those who taught them and remove them from the madrasas. The rulers of Damascus valued his opinion, and for years philosophy and logic were not taught there. His most quoted line, in the English of Goldziher’s translator, is that ‘the access to something bad is also bad’, logic being the access to philosophy.

Al-Nawawī (d. 676/1277), who later headed the same Dār al-Ḥadīth (from 665/1267), is named with Ibn al-Ṣalāḥ as forbidding logic in the later summaries of the debate, from the sixteenth-century jurist Aḥmad al-Ramlī to al-Akhḍarī’s Sullam. The text in which al-Nawawī stated this view is not identified in the sources consulted here, and the TDV’s article on al-Nawawī does not mention it.

4Ibn Taymiyya’s refutation

The Ḥanbalī theologian Ibn Taymiyya (d. 728/1328) went beyond prohibition to refutation. His Refutation of the Logicians (al-Radd ʿalā al-manṭiqiyyīn), begun under house arrest in Alexandria in 1309–10 and finished in Damascus, attacks Aristotelian logic in the form Ibn Sīnā gave it. Jon Hoover summarises his main arguments: definitions are matters of linguistic convention that distinguish one thing from another, and a definition gives no knowledge one did not already have; the syllogism is formally valid, but certain knowledge is often reached without it, and the number of premises a person needs varies with his ability; the categorical syllogism and the jurists’ analogy are equivalent, so that the logicians’ claim to superior certainty fails; and universal notions exist only in the mind, not as real essences in things.

He mocked the elaborate figures and conditions of the syllogism as ‘prolixity of little use and much weariness … lean camel meat on a rugged mountain peak that is not easy to climb’. Hoover notes that logicians of his own time and later paid the book little attention, partly because it ignored the newer logic of the thirteenth century. Its modern influence, through the Salafi movement, has been much greater. Wael Hallaq’s English translation, Ibn Taymiyya against the Greek Logicians (1993), is of al-Suyūṭī’s abridgement.

5Al-Suyūṭī and his critics

The Egyptian polymath Jalāl al-Dīn al-Suyūṭī (d. 911/1505) is the last of the opponents of logic cited by Goldziher. He abridged Ibn Taymiyya’s refutation, which, according to Mufti Ali, he rearranged into a clearer order than the original; he wrote Ṣawn al-manṭiq wa-l-kalām ʿan fannay al-manṭiq wa-l-kalām (roughly ‘Guarding speech from the two arts of logic and kalām’, edited by ʿAlī Sāmī al-Nashshār, Cairo 1947); and in a fatwā included in his al-Ḥāwī li-l-fatāwī, al-Qawl al-mushriq fī taḥrīm al-ishtighāl bi-l-manṭiq, he declared the study of logic forbidden. Ironically, his own small dictionary of the sciences gives the standard definition of logic as ‘a canonical instrument that protects the mind from error’.

Khaled El-Rouayheb argues that al-Suyūṭī’s view was not typical of his time. The Maghribī scholar Muḥammad ibn ʿAbd al-Karīm al-Maghīlī (d. 909/1503–4) objected to it while al-Suyūṭī was alive; his contemporary al-Sanūsī (d. 895/1490), one of the most influential theologians of North Africa, wrote several logic books; and the leading Shāfiʿī jurist of Cairo, Zakariyyā al-Anṣārī (d. 926/1520), wrote a famous commentary on the Īsāghūjī and defended the permissibility of logic in it. Two centuries later the Maghribī al-Ḥasan al-Yūsī (d. 1102/1692) answered al-Suyūṭī’s claim that logic is useless because universals have no existence outside the mind: universal propositions, he replied, are the basis of every science, whether law, theology or grammar, and the claim showed that al-Suyūṭī had no grasp of the rational sciences.

6Three positions

By the sixteenth century the debate had a standard summary. The Egyptian Shāfiʿī Aḥmad al-Ramlī (d. 957/1550), in a fatwā quoted by El-Rouayheb, gives three positions: Ibn al-Ṣalāḥ and al-Nawawī forbade it; al-Ghazālī said that the knowledge of one who does not know logic cannot be trusted; and the correct view is that it is permitted to a person of sound mind who holds to the Qurʾān and the Sunna. Logic, he adds, protects the mind from error in thinking as grammar protects the tongue, and it is a tool for learning the other sciences.

Al-Akhḍarī put the same summary into his Sullam: ‘On whether one may occupy oneself with it, the disagreement takes three positions: Ibn al-Ṣalāḥ and al-Nawawī forbade it; some said it ought to be learned; and the well-known, sound view is that it is allowed to one of complete intelligence, practised in the Sunna and the Book, so that he may be guided by it to what is right.’ Al-Azhar’s secondary-school textbook still teaches these verses, calling the three positions prohibition, permission (attributed to al-Ghazālī) and distinction (tafṣīl), the last being the correct one: logic is allowed to the intelligent student grounded in the Qurʾān and Sunna who can tell sound from unsound views, and forbidden to others.

The sources word the second position differently. Al-Ramlī and al-Mallawī attribute to al-Ghazālī the view that logic is necessary; the Sullam says only that ‘some said it ought to be learned’; and the Azhar textbook calls it ‘permission’. The third position is in any case conditional rather than a blanket permission.

7From permission to collective duty

Many mainstream jurists went further. Ibn Ḥajar al-Haytamī (d. 973/1566), whose fatwās carried great weight among Shāfiʿīs, cited al-Ghazālī’s Mustaṣfā and Munqidh and concluded that whatever serves the religious sciences is to be respected, so that learning and teaching logic is a collective duty (farḍ kifāya): a duty that rests on the community as a whole, which must ensure that some of its members master it. He added that a mujtahid needs logic, because every proof has conditions that logic sets out. He closed by quoting Tāj al-Dīn al-Subkī (d. 771/1370): logic is like a sword, with which one person fights in God’s cause and another robs travellers.

Al-Haytamī also explained the old prohibitions away: Ibn al-Ṣalāḥ and others, he said, meant ‘the logic of the philosophers’, not the logic known among Sunni scholars, which contains nothing of unbelief. The eighteenth-century commentators on the Sullam made this distinction standard. Aḥmad al-Mallawī (d. 1181/1767) wrote that there is no disagreement about the permissibility of logic that is not mixed with philosophy, as in the Sullam, the handbooks of al-Sanūsī and Ibn ʿArafa, the Īsāghūjī, the Shamsiyya, al-Khūnajī’s Jumal and al-Taftāzānī’s Tahdhīb, and that studying it is a collective duty, since answering heresies in theology is a collective duty and depends on it. Aḥmad al-Damanhūrī (d. 1192/1778), rector of al-Azhar in his last years, said the same, giving al-Bayḍāwī’s Ṭawāliʿ al-anwār as an example of logic mixed with philosophy, and so did the Mālikī ʿAlī al-ʿAdawī (d. 1189/1775).

El-Rouayheb adds a caution. The logic taught in Sunni madrasas was itself Aristotelian logic as reworked by Ibn Sīnā and his successors, so the line between ‘the philosophers’ logic’ and ‘the scholars’ logic’ is doubtful; the distinction seems to have served mainly to excuse earlier authorities who had opposed logic.

8Dissenters after 1500

There was no consensus. The Egyptian Ḥanafī jurist Ibn Nujaym (d. 971/1563) counted philosophy among the forbidden sciences and logic as part of philosophy, though his later commentators disagreed with him. In the seventeenth-century Ottoman Empire the Qāḍīzādeli movement kept hostility to logic alive: Kâtip Çelebi (d. 1067/1657) heard its leader Qāḍīzāde Meḥmed (d. 1045/1635–6) ask in a sermon who would shed a tear if a logician died, and himself regarded the movement’s followers as extremists. In Egypt Murtaḍā al-Zabīdī (d. 1205/1791) judged logic disliked (makrūh): basic logic might help other studies, but the Maghribīs went far beyond that, and logic encouraged pride and quarrelling and drew students away from hadith.

Others in the same circles praised it. The Ottoman scholar Ṭaşköprüzāde (d. 968/1560) called logic the highest of the instrumental sciences, comparing those who doubted it to the blind who cannot see the morning sun; Saçaklızāde (d. 1145/1732–3) held it commendable or a collective duty; and the Sufi ʿAbd al-Ghanī al-Nābulusī (d. 1143/1731) wrote a poem on logic. El-Rouayheb concludes that between 1500 and 1800 the mainstream in the Maghrib, Egypt and Turkey regarded logic as permissible, commendable or even a collective duty, and that opposition was a minority view.

9The modern debate

In the nineteenth and twentieth centuries the balance shifted. The Salafiyya movement, inspired partly by Yemeni scholars such as al-Shawkānī and partly by the Wahhabi movement, revived Ibn Taymiyya’s rejection of logic and theology; the Indian-born Ṣiddīq Ḥasan Khān, one of its most influential nineteenth-century figures, defended Ibn Taymiyya’s arguments against the logicians. At the same time al-Azhar went on teaching logic, and several of its rectors wrote on it.

Historians’ views changed too. In a classic article of 1916 Ignaz Goldziher wrote that after Ibn al-Ṣalāḥ and Ibn Taymiyya the study of logic came to be regarded as more or less forbidden, and later historians such as George Makdisi, Majid Fakhry and Jonathan Berkey echoed the picture. El-Rouayheb’s study of fatwās and debates from 1500 to 1800 (2004; Turkish translation 2019) calls this view ‘radically mistaken’ for that period. In his survey of 2019 El-Rouayheb notes that in the modern period opposition to logic has been strengthened by Salafism, while the third position of the Sullam is still taught in al-Azhar’s schools. Recent statements on both sides, including a fatwā of the former Grand Mufti of Egypt ʿAlī Jumʿa, are described in ‘Scholars on studying logic’.