Bishr ibn al-Mu'tamir

Abu Sahl Bishr ibn al-Mu'tamir ibn Bishr al-Hilali (died c. 210 AH / 825 CE) was a Muslim theologian usually credited with founding the Baghdad branch of the Mu'tazila, an early school of rational ("speculative") theology known as kalam. His birth date is unknown; he was an old man when he died, and sources are uncertain even about his birthplace, with Baghdad, Kufa, and Basra all proposed. He is reported to have studied kalam in Basra before relocating to Baghdad, where he established his own circle of students; among the best known were Thumama ibn Ashras and Abu Musa al-Murdar.

Bishr is most associated with the doctrine of tawallud (literally "generation") — the question of who is morally responsible for the secondary effects "generated" by a human act but not directly willed. He is described as holding people accountable for such effects, in keeping with the wider Mu'tazili emphasis on human free will and divine justice.

His writings, many in verse, survive only in fragments; two long poems on creation are preserved in the Hayawan ("Book of Animals") of his contemporary al-Jahiz. Tradition holds that Bishr leaned toward a Zaydi (a Shi'i) view of the caliphate — regarding Ali as the most excellent Companion while distinguishing excellence from the right of succession — and reports that the caliph Harun al-Rashid imprisoned him on suspicion of Shi'i sympathies before his release. These political details come from later biographical tradition and are presented here as reported, not established.