Al-Juwayni (Imam al-Haramayn) — Al-Ghazali's Teacher, the Greatest Ash'ari Theologian of His Era, Author of al-Irshad and al-Burhan, the Scholar Whose Systematic Kalam Laid the Foundation for Classical Sunni Theology's Mature Form

Al-Juwayni (الجُوَينِيّ; full name: Abu al-Ma'ali Abd al-Malik ibn Abdallah ibn Yusuf al-Juwayni al-Naysaburi; born 419 AH / 1028 CE in Juwayn, Khorasan; died 478 AH / 1085 CE in Nishapur; title: Imam al-Haramayn [Imam of the Two Sanctuaries — Mecca and Medina — where he taught for four years during the Ash'ari persecution under Seljuk vizier al-Kunduri, 1053-1058 CE]; the trajectory: studied under his father [a Shafi'i scholar] and then the leading scholars of Nishapur; after the persecution ended [al-Kunduri was executed by Nizam al-Mulk], returned to Nishapur and was appointed to teach at the new Nizamiyya Madrasa there [a different institution from the Baghdad Nizamiyya]; Nizam al-Mulk's patronage: the Seljuk vizier Nizam al-Mulk [1018-1092 CE] was the great patron of Ash'ari scholarship; he established the Nizamiyya madrasa system across the Seljuk empire; al-Juwayni's position at the Nishapur Nizamiyya was at the heart of this system; al-Ghazali: al-Ghazali studied under al-Juwayni for approximately 8 years in Nishapur; al-Juwayni reportedly predicted his student would 'drown scholars' [ghadda al-'ulama'] — he was right; al-Ghazali was his most famous and influential student; major works: [1] Kitab al-Irshad [The Book of Guidance]: systematic Ash'ari creed; organized around the 20 attributes obligatory to affirm for God [sifat wajibiyya], the 20 attributes impossible [sifat mustahila], and the 1 possible attribute [sifat ja'iza]; the most systematic presentation of Ash'ari theology up to his time; [2] Al-Burhan fi Usul al-Fiqh [The Proof in Legal Theory]: the most comprehensive usul al-fiqh work of the classical period; covers: the nature of divine command; the scope of rational qualification of revealed rulings; consensus [ijma']; analogy [qiyas]; preference [istihsan]; legal reasoning methods; [3] Ghiyath al-Umam [The Succor of Nations]: political theory; what should the Muslim community do if there is no legitimate imam/caliph? al-Juwayni's answer: governance structures that promote the public good are obligatory even without a legitimate imam; [4] Luma' al-Adilla [The Lights of the Proofs]: a shorter Ash'ari theology primer; theological positions: al-Juwayni's kalam combined Ash'ari theology with serious engagement with Mu'tazili arguments; he took the Mu'tazili challenge more seriously than earlier Ash'aris; his positions influenced his student al-Ghazali's more spiritually nuanced synthesis; on usul al-fiqh: al-Juwayni's al-Burhan represents the culmination of Shafi'i usul al-fiqh before al-Ghazali's al-Mustasfa took the field in a new direction; al-Juwayni introduced probabilistic reasoning [zann/yaqin distinctions] more rigorously than predecessors) is the master theologian who bridged early and mature Ash'ari kalam.