Many of the commentaries on Aristotle that a judge of Córdoba wrote in the twelfth century survive today only in Hebrew or Latin translation. By the 1230s Latin scholars called their author simply the Commentator. By 1340 nearly all his commentaries existed in Hebrew, though very little of Aristotle's own text did. Dante placed him in Limbo, among the virtuous who lived outside the Christian faith, as the man who wrote the great commentary. The author was Averroes, as Europe named him; in Arabic he was Ibn Rushd.
He came from a family of judges — his grandfather had been chief judge of Córdoba and imam of its Great Mosque — and he defended philosophy as a judge would. Around 1095 al-Ghazālī, the most celebrated theologian of his age, had declared the philosophers unbelievers on three points: that the world has no beginning, that God knows particular things only in a universal way, and that the resurrection of the body is a figure of speech. Averroes answered around 1179 in the Decisive Treatise, written in the form of a legal opinion. The religious Law, he argued, commands those able to follow a demonstration — a proof from certain premises — to study philosophy. One truth cannot contradict another, so where a proof clashes with the plain sense of a verse, the verse must be interpreted.
His work on Aristotle began with a commission from the court. In 1169 Ibn Ṭufayl, a philosopher and the caliph's physician, presented him to Abū Yaʿqūb Yūsuf, the Almohad caliph who ruled Morocco and al-Andalus, Muslim Spain. According to al-Marrakushī, a historian who finished his chronicle in 1224, the caliph asked whether the heavens had existed from eternity or had a beginning. Averroes, aware that a wrong answer could be dangerous, said nothing until the caliph had shown his own learning on the question. When the caliph later complained that Aristotle was hard to follow, Ibn Ṭufayl proposed Averroes as the one to explain him. Over the next quarter-century he wrote three kinds of commentary: short digests, close paraphrases, and long commentaries that quote Aristotle section by section. All the while he served as judge in Seville and Córdoba and, from 1182, as the caliph's physician.
The commentaries had a purpose beyond teaching. Averroes believed that Avicenna, the Persian philosopher of the early eleventh century, had departed from Aristotle on central points, and that al-Ghazālī's attack had landed on Avicenna's weak arguments rather than Aristotle's. In Tahafut al-Tahafut (The Incoherence of the Incoherence), written around 1180, he answered al-Ghazālī passage by passage. Its best-known pages defend cause and effect: to deny that fire burns cotton, he argued, is to deny that things have natures, and with them the possibility of knowing anything through its causes.
Late in life he reached the conclusion that made his name in Europe. In his long commentary on Aristotle's On the Soul he argued that the intellect which receives knowledge is one and the same for all human beings. In his earlier paraphrase of the same book he had called such a view repulsive. Read in Latin, this became the mark of Averroism. In 1270 the bishop of Paris condemned it among other teachings of the arts faculty's teachers there, and Thomas Aquinas wrote a treatise against those who held it. Critics also charged his Latin followers with a "double truth", one for philosophy and another for faith, which his own Decisive Treatise rules out.
In 1195 a tribunal in Córdoba condemned his teachings, ordered his books burned, and banished him to the nearby town of Lucena. Historians disagree about why: some point to the caliph al-Manṣūr's need for the religious scholars' support in his war against the Christian kingdoms, others to a personal offence or to the criticism of tyranny in his commentary on Plato's Republic. The caliph recalled him to Marrakesh, where he died in December 1198. His body was later carried back to Córdoba. Ibn ʿArabī, then a young man and later one of the most influential Sufi thinkers, attended the funeral there. He tells that the body was loaded on one side of a pack animal and, as a counterweight, the books Averroes had written on the other.
A long-repeated account holds that he had no successors in the Islamic world. Scholars now dispute it: one has identified thirty-nine of his direct disciples, and his work was still studied in North Africa and reached scholars in Iran by the sixteenth century. In the nineteenth century his name returned to Arabic debate in the nahḍa, the Arab cultural revival, where writers argued over what his defence of reason allowed.