Mu'tazilism

Mu'tazilism is a school of Islamic theology that first appeared in the early centuries of Islam, with its main centers in Basra and Baghdad. Its followers, known as Mu'tazilites, initially gained a reputation for staying neutral in the conflict between Ali and his adversaries, such as Mu'awiya, following the murder of the third caliph, Uthman. By the 900s, the label "al-muʿtazilah" specifically described a distinct tradition of speculative theology, or kalām, which was founded by Wasil ibn Ata. This later school built a rationalist approach to Islam around several core ideas: God's oneness (Tawhid) and justice (Al-'adl), human free will, and the belief that the Quran was created. The Mu'tazilites are most famous for opposing the view that the Quran is eternal and uncreated, arguing that if the Quran is God's speech, then God must logically exist before His own speech. This clashed with the common Sunni position—held by the Ashʿarī and Māturīdī schools—that because God is all-knowing, His knowledge of the Quran is eternal, making the Quran itself uncreated like Him. The school also tackled the problem of evil, reasoning that a just and wise God cannot command anything irrational or act without concern for His creatures; therefore, evil must come from human mistakes, arising from the free will God gave to people. The Mu'tazila rejected secular rationalism but held that human reason and intelligence could grasp religious principles, and that good and evil are rational categories discoverable through reason.

The movement reached its peak of political influence under the Abbasid caliphs during the mihna, an 18-year period from 833 to 851 CE. Caliph al-Ma'mun used this inquisition to persecute Sunni scholars—punishing, imprisoning, or even killing them—unless they accepted Mu'tazila doctrine. This policy was later reversed by al-Mutawakkil. The Aghlabid dynasty (800–909 CE) also adopted Mu'tazilism, making it the official creed of Ifriqiya. In Umayyad Spain, leading figures in the Graeco-Arabic translation movement under Caliph al-Hakam II (ruled 961–976) were Mu'tazilites. The school also saw some growth under the Buyid dynasty (934–1062 CE) in Iraq and Persia. Today, Mu'tazilism survives mainly in the Maghreb among groups calling themselves the Wasiliyah. It has also influenced the Quranist movement and the Neo-Mu'tazila literary approach to interpreting the Quran.

The name "Mu'tazili" comes from the Arabic root ع-ز-ل, meaning "to separate" or "withdraw." It originates from the founder's withdrawal from the study circle of Hasan al-Basri over a theological disagreement. Wasil ibn Ata asked whether a person who commits a serious sin is still a believer or an unbeliever. Hasan replied that the person remains a Muslim. Wasil disagreed, arguing the sinner is neither a believer nor an unbeliever, and left the circle. Others, including ʿAmr ibn ʿUbayd, followed him to form a new group. Hasan reportedly said, "Wasil has withdrawn from us," which is thought to be the origin of the movement's name. The group later called themselves Ahl al-Tawḥīd wa al-ʿAdl ("people of monotheism and justice"). The verb iʿtazala also means to take a neutral position in a dispute.

The Mu'tazila first appeared in early Islamic history during the conflict over Ali's leadership after Uthman's death. Those who took a middle position—neither condemning nor supporting Ali or his opponents at the battles of Siffin and Jamal—were called the Mu'tazila. By the 10th century, the term also referred to the school of speculative theology that flourished in Basra and Baghdad from the 8th to the 10th centuries. According to Sunni sources, Mu'tazili theology began in the 8th century in Basra when Wasil ibn Ata left Hasan al-Basri's lessons after a dispute about al-Manzilah bayna al-Manzilatayn (a position between two positions). Although later Mu'tazilis used logic and elements of early Islamic and ancient Greek philosophy, their starting point and ultimate reference remained the basics of Islam. Accusations from rival schools that they gave absolute authority to non-Islamic ideas reflect fierce theological polemics rather than objective reality. For example, most Mu'tazilis believed in creation ex nihilo, unlike some Muslim philosophers (except al-Kindi) who held some form of the world's eternity. Mu'tazili theology faced strong opposition from Hanbali and Zahiri traditionalists, as well as from the Ash'ari school (founded by a former Mu'tazili, Abu al Hasan al-Ash'ari) and Maturidi theologians.

Scholar Daniel W. Brown describes the Mu'tazila as "the later ahl al-kalām," suggesting the ahl al-kalām were their forerunners. The ahl al-kalām are remembered in Islamic history as opponents of Al-Shafi‘i, who argued that the final authority in Islam was the hadith of Muhammad, so that even the Quran should be interpreted in light of the hadith, not the other way around. Abu al-Hudhayl al-'Allaf (died 849 AD), who lived a few generations after the school's founding, was a key early figure in its development.