If you were asked to name the most important philosopher of 10th-century Baghdad, you would presumably not hesitate to say ‘al-Farabi’. He’s one of the few thinkers of the Islamic world known to non-specialists, deservedly so given his ambitious reworking of Platonic and Aristotelian metaphysics and political philosophy. But if you were yourself a resident of 10th-century Baghdad, you might more likely think of Yahya ibn ‘Adi. He is hardly a household name now but was mentioned by the historian al-Mas‘udi as the only significant teacher of Aristotelian philosophy in his day. But ibn ‘Adi is not just a good example of how fame wanes across the centuries. He is also a fine illustration of the interreligious nature of philosophy in the Islamic world.
Ibn ‘Adi was a Christian, as were most of the members of the group of philosophers who wrote commentaries on Aristotle at this time in Baghdad. The Muslim al-Farabi, who was apparently ibn ‘Adi’s teacher, was an exception to the rule. Completing the ecumenical picture, ibn ‘Adi was involved in an exchange of letters with a Jewish scholar named Ibn Abi Sa‘id al-Mawsili, who wrote to him with questions about Aristotle’s philosophy that he was hoping to have cleared up.