The differences between the Governmental Decrees, Istihsan and Masalih Mursalah

Explaining the differences between the "Governmental Decrees", "Istihsan" and "Masalih Mursalah" is one of the deep scientific problems which despite its many scientific and practical benefits, many of scholars have been confused about and unable to explain. Clarifying some of the problems of Islamic jurisprudence sources (Usul Al-Fiq), theology and social matters and its effect on many other sciences are some of its scientific results, and the effect of "Istihsan" and "Masalih Mursalah" on some of the "Governmental Decrees" are among the practical results of the discussion. The present paper is seeking to deliver a clear distinction between the three terms which depends on knowing the definition and the bases of each one from the perspective of Shi'a and Sunni schools. The outcome of the research is drawing four borders between them. At the first, the extension of the "Governmental Decrees" to all the people is discussed, i.e. the "Governmental Decrees" are binding to all people including the scholars and jurists. Then the evidences of validity are evaluated, since the "Governmental Decrees" have reliable reasons for validity, while the two others are not valid from perspective of Shi'a and some proofs support it. Then the quality of their validity is discussed. Another distinction that can be made between them is that the source of the "Governmental Decrees" can be the primary or secondary edicts, while the two others are independent reasons for jurisprudential edicts from the perspective of Sunnis. The other distinction is that of the subjects; the "Governmental Decrees" are temporary and depend on the time and place, while the results of" Istihsan" and "Masalih Mursalah" are general and inclusive. The present paper discusses the issues within four sections.