Life
Al-Farabi in their own century
Al-Farabi came from Farab, on the Jaxartes in Central Asia, and made his career in Baghdad when the translation movement had put most of Aristotle into Arabic within living memory. He taught logic, wrote on music with enough technical command that his Great Book of Music remained a reference for centuries, and left Baghdad late in life for the court of Sayf al-Dawla at Aleppo. He died in Damascus around 950, reportedly with very little to his name.
Ninth and tenth century Baghdad translated Greek philosophy and science on a scale not attempted before or since, largely through Syriac intermediaries. Al-Farabi worked in a city where Aristotle was newly available, where Christian, Muslim and Jewish scholars argued in the same rooms, and where the question of how revelation and demonstration relate was immediate rather than academic.
Central ideas
Logic before grammar
Against grammarians who held that reasoning is bound to the structure of a particular language, he argued that logic governs thought in any language at all. The claim mattered practically: it was what licensed reading Aristotle in Arabic as philosophy rather than as a foreign curiosity.
The virtuous city
His account of the excellent city takes Plato's Republic and sets it in a world that expects prophecy. The best ruler unites philosophical demonstration with the imaginative power that lets truth be communicated in images to those who cannot follow a proof, which makes religion, on this account, philosophy in figurative dress.
The Active Intellect
Human knowledge is completed when the intellect is illuminated by a separate Active Intellect rather than by its own effort alone. The doctrine came from late Greek readings of Aristotle's De Anima and became the shared framework within which Avicenna and Averroes disagreed.
Criticism & debate
His harmonising of Plato and Aristotle rested in part on a text, the so-called Theology of Aristotle, that is actually Plotinus, so some of the agreement he found was an artefact of the library he had. Later critics also pressed the political consequence: if religion is philosophy in images, the philosopher is quietly placed above the law he explains.
Influence
Avicenna records reading him to unlock Aristotle's Metaphysics, Averroes worked in his shadow, and Maimonides told a correspondent that al-Farabi's logical writings were worth more than anyone else's. Through them the framework reached Latin scholasticism.
How to read them
Begin Al-Farabi with the tension between logic before grammar and the virtuous city. Read the major works slowly enough to notice how biography, public crisis and method shape the argument rather than treating the thinker as a list of doctrines.
If Al-Farabi is right about logic before grammar, what habit of judgement would have to change first?