A Comparative Study of the Definition of Usul al-Fiqh based on the Juristic Principles of the Two Schools of Jurisprudence (Imamiyah and other Four Denominations)

One of the important and controversial juristic issues is the definition of Ilm al-Usul especially when it is examined comparatively. In view of the importance of this discussion in Ilm al-Usul, it is necessary to pay attention to the criteria and key components of a perfect definition. Without doubt, a perfect and inclusive definition is one that is characterized by a number of features and has certain components. In Usul or the science of legal theories an inclusive and exclusive definition is one that includes all the practical principles which form an important part of Usul discussion. Moreover, it should exclude jurisprudential rules (qawaed) and lexical issues which have nothing to do with it. Given their precision and careful thought, Muslim jurists have differed over the definition of Usul and have therefore offered various definitions. Therefore, as Akhund Khurasani has said a widely-known definition offered by Imamiyah jurisprudents is faulty and suffers from different problems. Also, Akhund Khurasani's definition is flawed according to Ayatollah Khoei because it is not inclusive and exclusive. Moreover, the definitions given by Sunni jurists also suffer from difficulties.