Al-Farabi arrived at the court of the Hamdanid Sayf al-Dawla al-Hamdani in Aleppo in the last years of his life. He was nearly seventy. He had been born in Farab in Turkestan, had come to Baghdad as a young man to study logic, had lived there for decades in modesty, wearing simple wool, teaching Aristotle to a small circle of students. He had written more than a hundred books. He was famous across the Muslim world. Sayf al-Dawla, the great cultural patron of the Hamdanid court, had invited him.
Al-Farabi accepted the invitation. He walked into the court dressed like a dervish, in wool, and Sayf al-Dawla, according to the account of Ibn Khallikan, did not know at first who he was. Al-Farabi sat down uninvited on the same platform as Sayf al-Dawla. Sayf al-Dawla whispered to a courtier: this old man does not know court manners. Have him removed. Al-Farabi replied in the same low voice: your majesty, I sit where my knowledge tells me to sit.
Sayf al-Dawla understood. He was talking to al-Muallim al-Thani. He turned to al-Farabi and said: welcome. He gave the philosopher food and dignity. Then, over the course of the evening, he asked al-Farabi to speak about the theory of music.
Al-Farabi had written the largest book on music of the Islamic middle ages, Kitab al-Musiqa al-Kabir, the Great Book of Music. It described the mathematics of the Arabic musical scales, the acoustics of stringed instruments, the physiology of hearing, the psychology of emotional response to music, and the moral effects of the different modes on the listener. The book had become the standard reference across the Muslim world.
Al-Farabi began to speak. He explained his theory of the modes. He explained how different musical scales produced different affects in the listener. He explained how the human ear was tuned by nature to certain intervals and not to others. He explained the mathematical ratios that underlie the pleasing scales.
Sayf al-Dawla's musicians were present. They were the finest musicians of the Hamdanid court. They listened skeptically. They knew music. Al-Farabi was speaking about it theoretically. Could he play?
Sayf al-Dawla asked al-Farabi if he had ever played. Al-Farabi said: I have written the theory. Then he asked for an ud, a lute. One was brought. He took it. He tuned it. He played.
He played a mode that made the whole court laugh. He played another that made everyone in the room cry. He played a third that made everyone feel sleepy. He played a fourth that made everyone alert. Every mode did what he had written it would do. The court musicians looked at each other.
Al-Farabi put down the ud and said: this is what I was describing in the book. The theory is the same as the practice. If a musician knows the modes, he can tune the emotion of a whole room.
Sayf al-Dawla asked him to stay at court. Al-Farabi stayed. He continued to write. He wrote his last works in Aleppo. He wrote al-Madina al-Fadila, the Virtuous City, which was a political treatise on the ideal Muslim polity modeled on Plato's Republic. The virtuous city, in al-Farabi's account, is ruled by a philosopher-prophet who understands both the metaphysical order of reality and how to translate it into political forms. The virtuous city is opposed to four kinds of unvirtuous cities: the ignorant city, the wicked city, the erring city, and the changed city. Each type of city corresponds to a type of soul. The virtuous city is the only one in which human beings can attain their highest happiness, because only in it are they governed by the intellect properly ordered.
This book became the founding text of Islamic political philosophy. Every later Muslim political philosopher, including Ibn Rushd, Ibn Bajja, and Ibn Sina, worked in dialogue with al-Farabi's virtuous city.
Al-Farabi died in Damascus in 950 CE at nearly eighty. According to some accounts he was killed by robbers on the road between Damascus and Ascalon. According to others, he died in his bed in Damascus, surrounded by his students. His tomb is in Damascus, in one of the classical cemeteries. Later Muslim philosophers used to travel to Damascus to visit it.
What the story teaches. A theory that cannot be played on the instrument it describes is not yet a theory. Al-Farabi could not simply write a book of music theory. He also had to play the ud. He had to demonstrate that the mathematics of the intervals corresponded to the actual emotional life of a listener. When the court musicians laughed, then wept, then grew sleepy, then alert, the theory was confirmed. Real knowledge, in al-Farabi's tradition, is knowledge that works in every mode it describes: theoretical, practical, and demonstrated. The Second Teacher earned his title by keeping the theory and the practice always in one hand.