Section 3

1. There is no considerable difference as to the principle which maintains that inference of religious decrees can be based on or supported by consensus of opinion (ijma'). But there are some dif­ferences as to what are the criteria of authority and authenticity (hujjiyyah) of ijma` (consensus of `ulama').

The Sunnis consider ijma ` as a credible and an authoritative source (hujjah) by itself as soon as a consensus is reached. But the Shiites say that &d' (consensus of `ulama') is absolutely valid only if confirmed by an infallible lmam (imam ma'sum).

2. Also, there are some differences as to the validity of reasoning by analogy (qiyas mustanbat al‑`illah). All the Sunnis, with the excep­tion of the Zahiris, believe this kind of analogical reasoning (qiyas) to be a legal authoritative source (hujjah). But the Imamiyyah Shiites, in addition to rejection on logical and rational basis of all the arguments of the Sunnis in favour of qiyas, consider it as unwarranted in the light of explicit traditions (riwdydt) of their infallible Imams.

3. As to the practice of istihsan (application of discretion in a legal decision; something that looks "good" and "advisable" to a jurist, but he can't argue convincingly in its favour), there are some differences among various Islamic sects. The Malikis, the Hanafis and the Hanbalis believe istihsan to be hujjah (an authoritative source for legal decisions). But the Shi’ah, the Shafi'is and the Zahiris do not regard it as hujjah. In this respect, the Shi'ah say: Some of the definitions given for "istihsan" supply no credible reasons for their support, whereas other acceptable arguments advanced under its title affirm the validity of something which is not "istihsan".

4. As to the "expediencies of the situation" (al‑masalih al­mursalah), many Sunnis, including Malik and Ahmad, consider them to be hujjah. That is, they infer religious decrees in accordance with expediences. But the Shiites and the Shafi'is do not regard al‑masalih al‑mursalah as hujjah. On the whole, in cases where inference has been made from expediences, in absence of a specific nass(explicit religious text or decree), the issue can be deduced from "general decrees" (nusus `ammah), or based on definite rational reasons; in such cases, no doubt, the inference is valid; however, its validity depends not on the basis of "expedience", but because of its compatibility with the "general decree" or on account of its rational basis. Otherwise, one cannot base an argument solely on "expediences" and pronounce a decree on this basis.

5. (Taswib wa takhti'ah): The Mu'tazilites and many of the leaders of Ahl al‑Sunnah believe that in cases other than those explicitly defined or ordered (ahka mansusah), the interpretation of the Divine decree is subject to the opinions of mujtahidin (authorities on religious law); or, if a real decree (hukm) does exist and the opinions of mujtahidin turn to be the contrary of that hukm, the real hukm undergoes change and the new one will be considered the real hukm. This viewpoint is called "taswib"(ratification). The Imamiyyah Shiites, as well as many other Muslims, believe that in all cases, whether an explicit decree (nass) exists or not, there is, in fact, a fixed unchange­able decree (hukm) which the mujtahid may or may not find out. This viewpoint is called "takhtiah" (fallibility of mujtahids).