The Princeton Encyclopedia of Islamic Political Thought

consensus

Consensus (ijmā‘), a technical term of Islamic jurisprudence, refers to the unanimous agreement of qualified jurists on a particular legal issue, the third of the four principal “sources” of Islamic law after the Qur’an and the sunna and preceding either qiyās (legal analogy) or ijtihād (exhaustive investigation of the bases of a legal ruling), according to most Sunni authorities. Twelver and Zaydi Shi‘is also accept the principle. Unlike the Qur’an and sunna, consensus is not a text from which law derives but a sanctioning device that guarantees the infallibility of the ruling subject to agreement, rendering it binding and theoretically removing it from the purview of subsequent challenge and review. Already by the early ninth century, legal theorists recognized consensus as a fundamental principle of legal hermeneutics: both Shafi‘i (d. 820) and Abu ‘Ubayd al-Qasim b. Sallam (d. 838–39) discussed it. The Mu‘tazili theologian Nazzam (d. 835–45) defined consensus as any opinion of which the truth has been incontrovertibly established, a view that suggests a reaction to the argument that consensus is a binding proof (ḥujja). Ja‘far b. Harb (d. 850), another Mu‘tazili, wrote a monograph on consensus. Consensus became a standard chapter in manuals of jurisprudence (uṣūl al-fiqh) by the late ninth century, as is evident from the extant references to the manuals of Dawud b. ‘Ali b. Khalaf al-Isfahani (d. 884), his son Muhammad b. Dawud (d. 910), and Muhammad b. Jarir al-Tabari (d. 923).

According to the classical theorists, the principle of consensus cannot be founded on reason because Jews, Christians, and other groups, despite their large numbers, agree on errors; mere agreement of a particular religious community, even other monotheists, does not guarantee truth. The probative nature of consensus is a special quality of the Muslim community conferred by divine grace, and proof of it must be provided by revelation. Among the most common texts cited as proof of the principle is the famous hadith report, “My community will never agree on an error.” In theory, consensus must be based on evidence, and even if the evidence is not known, it is assumed to have existed in the past. Objections in the classical sources question the ability to know that a consensus exists, suggesting that some scholars might remain silent, withholding their opinions out of fear or intimidation, yet the majority of Sunni jurists do not admit that this invalidates the authority (ḥujjīyya) of consensus.

Consensus is an important locus for defining the limits of acceptable religious interpretation and the boundaries of the interpretive community. According to some theorists, including Shafi‘i, consensus is of two main types: general consensus on matters such as the number of daily prayers or the obligation to perform the pilgrimage, in which the entire community participates, and scholarly consensus, or the agreement of jurists on more arcane legal issues. The latter is the type discussed in manuals of Islamic jurisprudence; this consensus is not the vox populi of Islamic societies but is more akin to scholarly consensus in a particular field of inquiry, such as astronomy or medicine.

Consensus, along with the institution of the legal madhhab (school of law), worked to control religious discourse and restrict religious authority to scholars who had been trained as jurists. Adherents of the Maliki legal madhhab held that ijmā‘ ahl al-madīna, the consensus of the scholars of Medina, was a binding authority, apparently on the grounds that the Medinan authorities preserved the traditions of the Prophet better than jurists elsewhere, but adherents of other Islamic legal traditions regularly rejected this position. The opinions of laymen were excluded from consideration, but so too were the opinions of authorities who were not trained jurists, including theologians, hadith experts, caliphs, and other rulers. The vehicle by which this act of exclusion was carried out was the institution of the legal madhhabs, which were established in the course of the ninth and tenth centuries. After that period, no scholar could voice opinions on Islamic law with authority unless he belonged to one of the accepted legal madhhabs. Tabari famously excluded Ahmad b. Hanbal (d. 855) from his historical survey of Islamic legal opinions, Ikhtilaf al-Fuqaha’ (The differing legal opinions of the jurists), on the grounds that he was merely a hadith scholar and not a jurist. The caliphs, who in an earlier period had been able to set precedent and change Islamic law of their own accord, were no longer granted the authority to do so. In addition, the theologians were denied consideration on the grounds that they lacked proper legal training. This effectively turned the table on the Mu‘tazilis, who had, in concert with the Abbasid caliphs, conducted an inquisition in the early ninth century to impose their views, including the doctrine that the Qur’an is created instead of eternal, on all prominent scholars. The Sunni jurists also rejected participation of the Shi‘is and Kharijis, arguing that their legal traditions were not historically valid. To work outside the legal madhhabs and to espouse opinions that were not represented within those traditions was to violate consensus (mukhālafat al-ijmā‘) or to deviate therefrom (al-khurūj ‘an al-ijmā‘), and whoever did so willfully was denounced as an unbeliever. By the mid-tenth century, groups threatened with exclusion from the consensus of the jurists reacted to the pressure to conform by affiliating with a particular legal madhhab. Ash‘ari theologians most often affiliated with the Shafi‘is and Mu‘tazili theologians with the Hanafis. Similarly, Shi‘is and Kharijis sometimes chose affiliation with a Sunni legal madhhab in order to participate in authoritative religious discourse. The Twelver Shi‘is affiliated first with the Zahiri madhhab, then with the Shafi‘is, while the Zaydi Shi‘is associated primarily with the Hanafis. Both the Twelvers and the Zaydis, however, would go on to claim that, since their legal traditions were as historically valid as those of the Sunnis and since the Sunnis’ definitions of consensus and their proof texts logically referred to them, their opinions should be considered in consensus as well.

The question of whose opinions counted for consensus defined the structure of the interpretive community. Debate on legal issues is based on the content of fatwas, or legal responsa, rather than the verdicts of judges. Though jurists were theoretically independent and equal and consensus was described as the end result of free battle of fatwas, in many Islamic societies there was a recognized hierarchy of authority among the jurists. Sayf al-Din al-Amidi (d. 1233), for example, refers to the senior jurists, whose opinions carry authority and thus are able to establish consensus, as ahl al-ḥall wa-l-‘aqd (the people of binding and loosing), borrowing a term that originally referred to those who chose a new caliph. Kamal al-Din Muhammad b. Humam (d. 1457) refers to “greater jurists” (akābir), who voice opinions on pressing issues, part of the process of reaching consensus, and “lesser jurists” (aṣāghir), who do not speak out on such issues but follow the greater jurists instead. The debate between these prominent jurists effectively settled new questions such as the legal status of opium, hashish, coffee, and tobacco or the legality of in vitro fertilization or cloning. Some theorists held that it was necessary for the entire generation of jurists who had formed a consensus to die out in order for the consensus to be recognized because one of them might change his mind before he died.

The establishment of a consensus on a particular point of law was usually negative and retroactive: consensus existed when there was an absence of conflicting opinion (khilāf), and many jurists would say that they knew of no dissenting opinion on an issue rather than claiming direct knowledge of a consensus. In addition, works on the disputed points of law were quite common, and the study of these issues formed the higher of two stages in advanced legal study, the first of which was devoted to the study of the standard legal positions (madhhab) of the tradition of legal study to which one adhered. Nevertheless, important works on the points of consensus included al-Ijma‘ (Consensus) by Abu Bakr Muhammad b. Ibrahim b. al-Naysaburi (d. 921), Maratib al-Ijma‘ (The degrees of consensus) by Ibn Hazm (d. 1064), and Naqd Maratib al-Ijma‘ (Refutation of the degrees of consensus) by Ibn Taymiyya (d. 1328). In a sense, ijmā‘ and khilāf are two sides of the same coin: the dissenting opinions of jurists whose opinions are taken into account in consensus are also considered valid contributions to legal debate. Ijmā‘ and khilāf together represent precedent: the historical record of opinions that must be taken into account by later jurists in arriving at an independent ruling. A description of the levels of consensus by Fakhr al-Islam al-Bazdawi (d. 1089) emphasizes this historical aspect. He distinguishes the consensus of the Prophet’s Companions, claiming that it is as strong as the Qur’an or a report attested by multiple chains of transmission (khabar mutawātir); the consensus of those after the Companions, which is of the same level of reliability as a well-known hadith report (ḥadith mashhūr); and a consensus that comes into being after dispute, the validity of which is comparable to a hadith report attested through a solitary chain of transmission. For this reason, knowledge of the points of consensus and dissent is often cited in lists of the requirements for ijtihād, or the ability to derive legal rulings through independent effort.

Consensus has binding authority, and a ruling sanctioned by consensus is understood to be an infallible representation of the divine law. In addition, many theorists hold that, if historical debate reveals two authoritative conflicting opinions on an issue, it is not permissible to adopt a third opinion. This appears to limit inquiry severely and dictate strict adherence to a traditional corpus of legal rulings. In practice, however, it was possible for jurists to propose new rulings by distinguishing the issue at hand from that which had been debated earlier or by showing that the earlier claims of consensus were not actually valid. The claim of consensus has often been used as a rhetorical device in legal debate, sometimes by authorities on both sides of a question and even when the ruling championed is arguably an innovation outside the traditional array of possible opinions. In the modern period, reformers found consensus a hindrance, since classical jurisprudence seems to prevent the origination of new rulings for old questions. Reformers such as Muhammad ‘Abduh (d. 1905) argued that consensus should be based on rational inquiry and therefore should be subject to revision and change with the changing circumstances of Islamic societies. Modern theorists have also argued that the circle of interpreters whose opinions should be taken into consideration should be widened to include experts in many fields, weakening the jurists’ claimed monopoly on authoritative religious discourse.