Islamic Studies 'Ilm al-Khilāf / Legal Controversy
Mourad Laabdi
  • LAST REVIEWED: 28 August 2018
  • LAST MODIFIED: 28 August 2018
  • DOI: 10.1093/obo/9780195390155-0257


Multiplicity and conflict of opinion played a decisive role in the development of Islamic law (fiqh) and legal theory (uṣūl al-fiqh). The scholarly activity that best represented legal diversity and Muslims’ acceptance of it is a body of knowledge called “the science of disagreement” (ʿilm al-khilāf). This is not the knowledge of the conflicts between the companions of the Prophet (ikhtilāf al-ṣaḥāba), which was also considered by the ancient authorities a requisite for exercising ijtihād and issuing fatwā. ʿIlm al-khilāf, close in its spirit of inquiry to modern comparative law, is the systematic investigation of the differences and similarities of the various Sunni schools of law on a wide range of key legal questions. It emerged as a subfield of the legal study at the end of the 8th (AH 2nd) century. Like other Islamic sciences, its heyday was the classical period, especially between the 8th (AH 2nd) and 12th (AH 6th) centuries, during which a vast number of exceptional works of khilāf was produced. In addition to “ʿilm al-khilāf,” Muslims used slightly different names to refer to the study of juristic disagreement, including ʿilm al-ikhtilāf, ʿilm al-ikhtilāfāt,ʿilm al-khilāfiyyāt, and simply the modifiers without the noun ʿilm. Some modern scholars have made a conceptual distinction between khilāf and ikhtilāf and claimed that, contrary to ikhtilāf, khilāf implies a deplorable form of divergence and is legally disapproved. However, as far as both expressions were used by the classical lawyers, they represented the same semantic category: the comparative study of disagreements in legal matters. It is the intricate relationship between the methods of juristic disagreement and associated fields, such as dialectic (jadal) and disputation (munāẓara), that sometimes caused confusion about whether khilāf is a domain of theology or law. The main reason was the nature of ʿilm al-khilāf and its curricular training. For, traditionally, law students had to acquire the techniques of dialectic and disputation before they qualified for engaging in the study and practice of juristic khilāf. The literature of ʿilm al-khilāf may be categorized into two main classes: theoretical and practical. Practical studies of khilāf have a practical goal in sight and often seek to settle juristic controversies. They are written in conformity with the style and structure of works of substantive law (furūʿ). Essentially, they are works of fiqh with a comparison twist. Theoretical studies of khilāf, on the other hand, approach jurists’ disagreements not for their practical use, but for comparing the methods that informed their conclusions and gave rise to their differences. As such, they are a field of uṣūl al-fiqh. Practical, or theoretical, khilāf studies can be further divided into two important groups: inter-madhhab and intra-madhhab. Inter-madhhab khilāf studies explore jurists’ disagreements across the different schools of law, and do so either impartially and objectively, or to promote the legal hermeneutics of the author’s school. Intra-madhhab studies focus on disagreements within one’s school, and played a crucial role in laying the foundations for later methods of legal theory, such as legal maxims (qawāʿid) and extrapolation (takhrīj).

General Overviews

In the mid-19th century, Ignaz Goldziher urged the need for a bibliographical study of khilāf (see Goldziher 2008, p. 36). His call was restated about eighty years later by Franz Rosenthal in his translation of the Muqaddima of Ibn Khaldūn (see Volume 3 of Ibn Khaldūn 1967, p. 30). But, it was Joseph Schacht who showed close interest in this subject matter during the 1960s, first in his Origins of Muhammadan Jurisprudence and then in a separate essay, “Ikhtilāf,” in The Encyclopaedia of Islam. A more comprehensive account was published about three decades later by Mohammad Hashem (Kamali 1998). More recently, Abdul Wahid Hamid produced a translation of Jabir Alalwani’s Adab al-Ikhtilāf (The ethics of disagreement in Islam), a full survey of the science of juristic disagreement, its emergence, development, and techniques (see Alalwani 2011). In non-European languages, ʿilm al-khilāf has been at the center of Muslim scholars’ research. Whereas the majority of publications about it have been in Arabic, there are important surveys in other languages as well, such as Şükrü Özen’s “Hilaf” in TDV Encyclopedia of Islam (Istanbul: Centre for Islmic Studies in Turkey, 1998).

  • Alalwani, Taha Jabir. The Ethics of Disagreement in Islam. Translated by Abdul Wahid Hamid. London and Washington, DC: International Institute of Islamic Thought, 2011.

    One part of his discussion explores lexical and conceptual questions of ikhtilāf and surveys its development up to the second generation. Another compares the differences between the legal hermeneutics of the Sunni schools of law and analyzes their causes. The third part establishes an ethical system of disagreement by scrutinizing how the legal authorities of the post-taqlīd period engaged with and responded to one another. The original work: Adab al-Ikhtilāf fī al-Islām (Herndon, VA: International Institute for Islamic Thought, 1992).

  • Charnay, Jean-Paul. “Fonction de l’Ikhtilāf en Méthodologie Juridique Arabe.” In L’Ambivalence dans la Culture Arabe. By Jean-Paul Charnay, 191–231. Paris: Anthropos, 1967.

    An excellent critical survey that situates juristic disagreement within the larger context of Muslims’ debate and tolerance of intellectual differences and contradictions with respect to other scholarly fields, such as Qurʾanic exegesis and Hadith criticism. It also coins a unique view of khilāf as a “psychological tranquilizer” that, by allowing differences in legal matters susceptible to ijtihād, it played a significant role in sustaining the unity of the “orthodox” creed of the Muslim community.

  • Goldziher, Ignaz. The Ẓāhirīs, Their Doctrine and Their History: A Contribution to the History of Islamic Theology. Translated and edited by Wolfgang Behn. Leiden, The Netherlands: Brill, 2008.

    With an introduction by Camilla Adang, includes two particularly useful discussions. An analysis of the theological principle that sustained the schools’ toleration of disagreement, the Prophet’s saying: ikhtilāf ummatī raḥma (the difference of opinion within my community is an act of mercy from God). An appendix, “ʿIlm al-Ikhtilāfāt,” that explains the thematic and methodological nature of ʿilm al-khilāf with special focus on Ibn Ḥazm’s position. The original work: Die Ẓâhiriten, ihr Lehrsystem und ihre Geschichte: Beitrag zur Geschichte der Muhammedanischen Theologie (Leipzig: O. Schulze, 1884).

  • Ibn Khaldūn. Al-Muqaddimah: An Introduction to History. 3 vols. Translated by Franz Rosenthal. Princeton, NJ: Princeton University Press, 1967.

    Appended to Ibn Khaldūn’s chapter on fiqh and uṣūl al-fiqh in the Muqaddima is a succinct historical survey of juristic disagreement entitled “al-Khilāfiyyāt.” It defines the khilāf genre, establishes its value for the study of Islamic law and legal theory, explains its development after the formation of the Sunni schools of law, and lists select key classical studies of it.

  • Kamali, Mohammad Hashim. “The Scope of Diversity and ‘Ikhtilāf’ (Juristic Disagreement) in the Sharīʿa.” Islamic Studies 37.3 (1998): 315–337.

    Begins with a discussion of the role of khilāf in light of the principle of ijmāʿ and the doctrine of monotheism (tawhid), and then elaborates on the main causes of disagreement (asbāb al-khilāf) and its established etiquette (adab al-khilāf), and its varieties and styles (praiseworthy versus blameworthy disagreements). The survey also includes an analysis of two applied cases of juristic disagreement to explains concretely the methodological process of engaging with a controversial legal question.

  • Kamali, Mohammad Hashim. “Disagreement (Ikhtilāf) and Pluralism in the Sharīʿah.” In Sharīʿah Law: An Introduction. By Mohammad Hashim Kamali, 99–122. Oxford: Oneworld, 2008.

    A reproduction of his “The Scope of Diversity” with minor revisions and insertions of Arabic texts.

  • Makdisi, George. The Rise of Colleges: Institutions of Learning in Islam and the West. Edinburgh: Edinburgh University Press, 1981.

    Of particular relevance in this seminal study is a section entitled “The Antithesis of Ijmāʿ-‘Khilāf” on the role of khilāf as a scholastic method for learning in legal studies and other fields, such as philosophy and theology (pp. 107–111). It also provides a useful explanation of the difference between the concepts of khilāf (disagreement), jadal (dialectic), and munāẓara (disputation), which can be and have been confused.

  • Schacht, Joseph. “Ikhtilāf.” In The Encyclopaedia of Islam. 2d ed. Edited by Peri Bearman, Thierry Bianquis, Charles Bosworth, Emeri van Donzel, and Wolfhart Heinrichs. Leiden, The Netherlands: Brill, 1960–2007.

    First published online in 2012. Introduces the theological debate behind juristic disagreement and explains the ways in which tolerating difference of legal opinion among the Sunni schools of law was sustained by the principle of consensus (ijmāʿ). It discusses the emergence of khilāf writings and cites select classical (and one modern) titles, and refers to a few contemporary initiatives to create a unified Sunni legal system and bridge the gap between the legal hermeneutics of the Sunnis and Shiʿis.

  • Schacht, Joseph. Origins of Muhammadan Jurisprudence. Oxford: Oxford University Press, 1967.

    Schacht designates the last section of chapter 8, entitled “Disagreement,” to the issue of ʿilm al-khilāf. It introduces the views of al-Shāfiʿī on juristic disagreement and analyzes his acceptance of it as an inevitable historical development of the implementation of analogy (qiyās) and the rise of independent reasoning (ijtihād) in the Islamic legal praxis.

  • Walbridge, John. “The Islamic Art of Asking Questions: ʿIlm al-Ikhtilāf and the Institutionalization of Disagreement.” Islamic Studies 41.1 (2002): 69–86.

    Approaches khilāf as a social and historical phenomenon and examines the ways in which medieval Muslims established and sustained consensus about managing and engaging with disagreements in religious and legal matters. In addition, it elaborates on the question of disagreement in the contemporary Islamic world in light of the collapse of traditional Islamic education and the rise of neo-Hanbalism and its various Wahhabi forms.

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