Jurisprudence is a science that modifies practical aspects of an Islamic society. In accordance with changing society's jurists, relying on the principles of jurisprudence thought as the foundations of jurisprudence have continuously striven to infer Sharia Law rulings. Upon a closer look, it becomes clear the principles of jurisprudence in their own terms rely on other principles that are mostly ignored and have a more pivotal role in inferring rulings compared to the principles of jurisprudence. Assumption is a comprehensive view and an overall reading of the religion by the jurist upon which he acts to lay down the overall rules and principles of jurisprudence. Assumption is influenced by a realm of information, personal tendencies and social circumstances and the main cause of differences in the jurisprudence of religions should be sought in the differences of assumption s. The current paper after describing the nature of the science of jurisprudence and principles of jurisprudence is concerned with the concept and fundamental state of assumption s. The paper via presenting a practical sample of the formation of juridical assumption strives to deal with its critical role and effect in the creation of two sciences of jurisprudence principle and jurisprudence as well as a juridical Mujtahed's (religious leadership) juridical attitude so that in this channel the necessity for understanding, reviewing and measuring the assumption s in the Islamic jurisprudence are explained.
