The Development of Quinque Voces: Aristotle, Porphyry, Farabi, Ibn Sina



To analyze the dialectical reasoning, in Topics, Aristotle reduces any dialectical proposition to a subject which is ‘species’ and a predicate which is either ‘definition’ , ‘genus’, (‘difference’,) ‘property’, or ‘accident’, and then he says that the ten categories provide the matters of these predicables. Porphyry in Isagoge substitutes the ‘species’ for the ‘definition’ and exhibites these five universal predicates as the necessary or useful introduction to the Aristotelian doctrines of categories, definition, devision, and proof. Farabi combines Aristotelian Predicables with Porphyrian Five Universals and make a new catalogue of universals. He also explains that the five universals are final elements of all definitions and reasonings in all sciences. Ibn Sina in the logic of al-Shifa’ which is the best representative of the nine-part logicography in Islamic world, applies the five universals in the same function as Porphory does in Isagoge; but in the logic of al-Isharat which is the first compelet representative of his bipartite logicography, he applies them only as an introduction to the theory of definition