Al-Farabi
Persian/Turkic philosopher, logician and music theorist (c. 872–950), probably born in Farab, in present-day Kazakhstan, and educated in Baghdad, where he studied Aristotelian logic under Nestorian Christian masters, a grounding that earned him the medieval Latinised name 'Alpharabius' and the Arabic honorific 'Second Teacher' (al-Muallim al-Thani), second only to Aristotle himself, for the depth and systematic rigour with which he commented on and synthesised the Greek logical and metaphysical corpus for the Islamic world. His most influential work, The Virtuous City (Al-Madina al-Fadila), adapts the Platonic model of the ideal republic to an Islamic context, proposing that the perfect political community must be governed by a philosopher-prophet capable of receiving truth both rationally (philosophy) and through revelation (prophecy), a figure in whom the highest intellectual knowledge and the community's spiritual guidance converge. Al-Farabi also developed an influential emanationist theory of the universe, inspired by Neoplatonism, according to which all reality flows hierarchically from a necessary First Being through a series of cosmic intelligences down to the material world, a scheme Avicenna would later adopt and develop further. As a music theorist, his Great Book of Music (Kitab al-Musiqa al-Kabir) stands as one of the most systematic treatises on musical theory of the entire Middle Ages, combining mathematical analysis of intervals with philosophical reflection on the psychological and ethical effects of music. His synthesis of Aristotelian logic, Neoplatonic metaphysics and Islamic theology exerted a decisive influence both on later Muslim philosophers — Avicenna, Averroes — and, through medieval Latin translations, on Western Christian scholasticism.