Career
He wrote al-Mu'tamid fi usul l-fiqh, a major source of influence in the field of usul until Razi's Mahsul. He was a physician as well as a disciple of the Qadi Abd al-Jabbar in Rey. He challenged some of his master’s teaching and eventually compiled a huge (two volumes.
1500 pages) critical review of the arguments and proofs used in Islamic Scholastic Theology. This he summarised in al Mu'tamad "The Reliable". He including a critique of the qualifications a scholar of Islamic law needed to practice.
