Confidence or certitude (iṭmiʾnān) plays a significant role in jurisprudence and principles of Islamic law (uṣūl). Establishing many topics in jurisprudence and principles of Islamic law is dependent on attaining confidence. The majority of scholars recognize its authority (ḥujjiyah) based on the observation that confidence is considered equivalent to knowledge in common usage, language, or the established practice of religious scholars and rational individuals. Some scholars even went as far as to say that it is impossible to refute this practice. Others argued that the basis for the authority of certainty (qataʿ) is confidence and peace of mind. Sayyid al-Ṣadr provided a detailed analysis of the sources of confidence. If it is derived from a weak quantitative factor, then it is not considered authoritative. However, al-Muhaqqiq al-Iraqi, al-Muhaqqiq al-Isfahani, al-Muhaqqiq al-Ᾱshtiyāni, and Sayyid al-Saʿīd al-Hakīm (may God bless them all) disagreed with its authority. They supported their claim after discussing the arguments of the proponents and concluding that there is no evidence to support the equivalence of confidence to knowledge in common usage or language, and that there is no established practice (sīrah) supporting its authority. They presented an obstacle and a deterrent to the authority of rational confidence, which is the generality of the evidence supporting the authorities, such as the principle of practical principles of Islamic law (usūl ʿamaliyya), the evidence of clear signs (bayyina), and a number of narrations. Sayyid al-Saʿīd al-Hakīm has cited narrations to support the non-authority of confidence. However, His Eminence has stated that none of them adequately supports his claim. His main argument is that there is no basis for the authority of rational confidence in the presence of the possibility of disagreement among the jurisprudents. Otherwise, if the existence of the practice (sīrah) is accepted, then there is nothing to prevent it.