Abstract

The definition of essential accidents and the criterion for distinguishing them have been extensively discussed in the field of philosophical-logical epistemology and the case studies conducted in this area. Such a definition and its distinguishing criterion are helpful in philosophers' conceptualization of the definition of the subject of science.Aristotle, who, on the basis of his ontological theories, believed that arguments were based on cause-effect relationships, viewed demonstrable knowledge as being restricted to essential accidents. However, Farabi, relying on the definition which he provided for essential accidents, and which was later repeated by Ibn-Sina in al-Isharat, maintained that since constitutive essence is never questioned, it is only used in the premises of the argument, and that what is employed in problems belongs to the category of essential accidents.Ibn-Sina's commentators, such as Fakhr al-Din Razi and Nasir al-Din Tusi, have provided alternative interpretations of the definition of essential accidents in al-Shifa and in Ibn-Sina's other works, particularly in al-Isharat. Considering the importance and ambiguity of this issue, a close study and analysis of the differences among the commentators will illuminate a number of complicated points.