Isaac Albalag was a thirteenth-century Jewish philosopher active in Catalonia or southern France, best known for his Hebrew translation and critical commentary on al-Ghazali's Maqasid al-Falasifa, which he titled Tiqqun ha-De'ot (Emendation of Opinions). A committed Averroist, he held that philosophical and theological truths belong to entirely separate epistemic domains — an early and explicit articulation of the double truth doctrine in Jewish thought. He engaged critically with Avicenna's metaphysics, particularly rejecting the Avicennian proof for God's existence via the necessary/contingent distinction in favor of an Aristotelian-Averroistic framework.
Translated al-Ghazali's Maqasid al-Falasifa into Hebrew as Tiqqun ha-De'ot, with original critical glosses
Articulated an explicit double truth doctrine separating the domains of philosophy and revealed religion
Critiqued Avicenna's necessary/contingent proof for the Necessary Existent on Averroist metaphysical grounds
Introduced rigorous Averroistic method into medieval Hebrew philosophical literature
Argued that Aristotelian cosmology, including eternal creation, need not be reconciled with Torah on philosophical terms