History of Development of the Status of Reason in Deduction from Sheikh Mufid to First Martyr

It is widely known and stated in the works by recent scholars that the sources of Shi’i thought and derivation of Islamic laws, according to Imamiyyah (Shia), are three: Quran, Sunnah, consensus and intellect. In spite of this extensive reputation in the historic and content-related attitude, there is ambiguity around the fourth source of Islamic law. Thus, when studying the juridical system of every jurist, one must see as to how he defines intellect or reason. Some of the historical manifestations of the proof of intellect are the applicable principles such as the principle of presumed innocence and presumed continuity (Ghazzali, 1420:1/2/217,221) and some others are the methods of understanding and deciphering the speech (Mohaqqiq Hilli, 1418: 1/31). In this study, the viewpoint of prominent jurists from the Shia School of Jurisprudence, from Sheikh Mufid to First Martyr (Muhammad Jamaluddin al-Makki alAmili), have been studied. With a view to the developments and changes in the place of reason in deduction, the innovations and novel thoughts of each jurist have been meticulously pointed out and discussed .