Wasil ibn Ata in the context of "Mu'tazilism"

Mu'tazilism (Arabic: المعتزلة, romanized: al-muʿtazila, singular Arabic: معتزلي, romanized: muʿtazilī) is an Islamic theological school that appeared in early Islamic history and flourished in Basra and Baghdad. Its adherents, the Mu'tazilites, were known for their neutrality in the dispute between Ali and his opponents such as Mu'awiya after the death of the third caliph, Uthman. By the 10th century the term al-muʿtazilah had come to refer to a distinctive Islamic school of speculative theology (kalām). This school of theology was founded by Wasil ibn Ata.

The later Mu'tazila school developed an Islamic type of rationalism, based around fundamental principles: the oneness (Tawhid) and justice (Al-'adl) of God, human freedom of action, and the creation of the Quran. The Mu'tazilites are best known for rejecting the doctrine of the Quran as uncreated and co-eternal with God, asserting that if the Quran is the literal word of God, he logically "must have preceded his own speech". This went against a common Sunni position (followed by the Ashʿarī and Māturīdī) which argued that with God being all-knowing, his knowledge of the Quran must have been eternal, hence uncreated just like him. The school also worked to resolve the theological "problem of evil", arguing that since God is just and wise, he cannot command what is contrary to reason or act with disregard for the welfare of His creatures; consequently evil must be regarded as something that stems from errors in human acts, arising from man's divinely bestowed free will.The Mu'tazila opposed secular rationalism, but believed that human intelligence and reason allowed Man to understand religious principles; that good and evil are rational categories that could be "established through reason".