Al-Farabi made contributions to the fields of logic, mathematics, music, philosophy, psychology, and education.
Alchemy
Al-Farabi wrote: The Necessity of the Art of the Elixir.[61][N]
Logic
Though he was mainly an Aristotelian logician, he included a number of non-Aristotelian elements in his works. He discussed the topics of future contingents, the number and relation of the categories, the relation between logic and grammar, and non-Aristotelian forms of inference.[62] He is also credited with categorizing logic into two separate groups, the first being "idea" and the second being "proof".
Al-Farabi also considered the theories of conditional syllogisms and analogical inference, which were part of the Stoic tradition of logic rather than the Aristotelian.[63] Another addition al-Farabi made to the Aristotelian tradition was his introduction of the concept of "poetic syllogism" in a commentary on Aristotle's Poetics.[64]
Music
Drawing of a musical instrument, a shahrud, from al-Farabi's Kitab al-Musiqi al-Kabir[D]Al-Farabi wrote a book on music titled Kitab al-Musiqi al-Kabir (Grand Book of Music).[65][D] In it, he presents philosophical principles about music, its cosmic qualities, and its influences, and discusses the therapeutic effects of music on the soul.[66] He moreover talks about its impact on speech, clarifying how actually to fit music to speech, i.e., poetry, in arrange to upgrade the meaning of a text.[67]
Philosophy
Gerard of Cremona's Latin translation of Kitab ihsa' al-'ulum ("Enumeration of the Sciences")[F]As a philosopher, al-Farabi was a founder of his own school of early Islamic philosophy known as "Farabism" or "Alfarabism", though it was later overshadowed by Avicennism. Al-Farabi's school of philosophy "breaks with the philosophy of Plato and Aristotle [... and ...] moves from metaphysics to methodology, a move that anticipates modernity", and "at the level of philosophy, Farabi unites theory and practice [... and] in the sphere of the political he liberates practice from theory". His Neoplatonic theology is also more than just metaphysics as rhetoric. In his attempt to think through the nature of a First Cause, Farabi discovers the limits of human knowledge".[68]
Al-Farabi had great influence on science and philosophy for several centuries,[69] and was widely considered second only to Aristotle in knowledge (alluded to by his title of the "Second Teacher"),[C] in his time. His work, aimed at synthesis of philosophy and Sufism, paved the way for the work of Avicenna.[70]
Al-Farabi also wrote a commentary on Aristotle's work, and one of his most notable works is Ara Ahl al-Madina al-Fadila,[E] where he theorized an ideal state, supposedly modelled on Plato's The Republic.[71] Al-Farabi argued that religion rendered truth through symbols and persuasion, and, like Plato, saw it as the duty of the philosopher to provide guidance to the state. Al-Farabi incorporated the Platonic view, drawing a parallel from within the Islamic context, in that he regarded the ideal state to be ruled by the Prophet-Imam, instead of the philosopher-king envisaged by Plato. Al-Farabi argued that the ideal state was the city-state of Medina when it was governed by Muhammad as its head of state, as he was in direct communion with Allah whose law was revealed to him. In the absence of the Prophet-Imam, al-Farabi considered democracy as the closest to the ideal state, regarding the order of the Sunni Rashidun Caliphate as an example of such a republican order within early Muslim history. However, he also maintained that it was from democracy that imperfect states emerged, noting how the order of the early Islamic Caliphate of the Rashidun caliphs, which he viewed as republican, was later replaced by a form of government resembling a monarchy under the Umayyad and Abbasid dynasties.[72]
Physics
Al-Farabi wrote a short treatise "On Vacuum", where he thought about the nature of the existence of void.[73] His final conclusion was that air's volume can expand to fill available space, and he suggested that the concept of perfect vacuum was incoherent.[73]
Psychology
In his Opinions of the People of the Ideal City,[E] al-Farabi expressed that a separated person may not accomplish all the idealizations by himself, without the help of other people. It is the intrinsic mien of each man to connect another human being or other men within the labor he has to be performed. Subsequently, to realize what he can of that flawlessness, each man must remain within the neighborhood of others and relate with them.[66] In chapter 24 of aforementioned text—On the Cause of Dreams, he distinguished between dream interpretation and the nature and causes of dreams.[66]
