Abu Ali al-Jubba'i

Abu Ali Muhammad ibn Abd al-Wahhab al-Jubba'i (235/849–303/915) was one of the leading theologians of the Mu'tazila, a rationalist current in early Islamic thought that made reasoned argument central to discussing God. (The Mu'tazila were a distinct school of kalam; later Sunni orthodoxy came to regard them as heterodox, while they are esteemed in much of the rationalist and Shia tradition — so he is best described as a Mu'tazili rather than placed within any later confessional camp.) He takes his name from Jubba, a town in Khuzistan (south-western Iran), and built his career in Basra, in southern Iraq, where sources report he studied under the Mu'tazili master Abu Ya'qub al-Shahham and went on to lead the Basran branch of the school. After his death his son, Abu Hashim al-Jubba'i, continued the school; together the two are often called "the two shaykhs" of Basran Mu'tazilism.

The Mu'tazila held that God's absolute oneness (tawhid) means God's "attributes" cannot be eternal things alongside Him, and that God, being perfectly just, does not do wrong — humans therefore bear real responsibility for their acts. Al-Jubba'i is remembered for sharpening these positions, including debates over whether God is bound always to do what is "most beneficial" (al-aslah) for people; reports indicate he qualified rather than fully embraced the strongest form of that claim.

He is best known in later memory as the teacher of Abu al-Hasan al-Ash'ari, who broke with him and founded the rival Ash'ari school. The famous account of their split over the "problem of the three brothers" circulates widely in tradition; modern scholars treat the anecdote as a teaching story whose historical details are uncertain. The Mu'tazili and Ash'ari assessments of who had the better argument differ and are presented here as positions, not as settled fact. He died in 303/915-6; the sources are silent or divided on where (Basra and Askar Mukram are both reported), so the death-place is not firmly fixed.