Sunnah, or the process of Ijma. Third, there must be a common illa, or reasoning, which applies to both cases in an analogous way. These three conditions allow for a hukm to be made on the new case based on the analogical connection to the reasoning from the original case. Shi’a interpretations Not unlike the Sunni Hanbalis and Zahiris, the Shi’a rejected both pure reason and analogical reason completely on account of the multitude of perspectives that would arise from it, viewing both methods as subjective. There are various instances in which the Quran disapproves of a divergence of beliefs such as the following: Twelver Shi’a Within the Twelver Shi’i legal tradition, the fourth source for deriving legal principles is not qiyās but rather the intellect ’’'Aql’’. Twelver Shi’a regard the ulama (scholars) as authorities in legal and religious matters during the Occultation (ghayba) of the Imamah Mahdi. Until the return of the hidden Imam, it is the responsibility of the ulāma’ to be his deputies and provide guidance on worldly matters. In modern interpretations of Twelver Shi’ism, the most revered and learned scholars are styled as references for emulation (marja taqlīd). This system of deriving legal principles effectively replaces both the Sunni notion of consensus (ijmā’) and deductive analogy (qiyās) Accordingly, in the chapter on Knowledge of the Twelver collection of prophetic traditions, Kitab al-Kafi, one finds many traditions cited from the Imams that forbid the use of qiyās, for example: Ismaili Shi’a Among the most notable Ismaili thinkers, Bu Ishaq Quhistani regarded the notion of subjective opinion (qiyās) as completely contradictory to the Islamic notion of tawhīd (unity) as it ultimately gave rise to a countless divergent conclusions, besides which those who exercised deductive analogy relied on little more than their imperfect individual intellects. According to Bu Ishaq, there must be a supreme intellect in every age, just as Muhammad was in his time. Without this, it would be impossible for any ordinary individual to attain knowledge of the Divine using mere speculation. The supreme intellect, he reasoned, could be none other than the Imam of the age. Bu Ishaq Quhistani referred to the Quranic tale of Adam and Eve to support his argument for the necessity of a perfect teacher who could provide spiritual edification (ta’līm) in place of what he felt were subjective whims and wayward personal opinions (ra’y). Commenting on the Quranic foundational narrative, Bu