Istihsan means to see...

Istihsan means to see, quite independently, without taking similar cases into account, what is nearest to the truth and to justice, and to give one's opinion according as one's inclination and intellect approve.

Similarly with istislah [determining what is in the interests of human welfare by one's own deliberationsl, which means the seeming of one thing as more expedient than another, and ta`awwul in which, although a ruling may have been reached in one of the nusus [the textual bases for a precept of the shari`a sing.: nass], in a verse from the Qur'an or in a hadith from the Prophet, one still has the right, for some reason, to dispense with the contents of the nass and to give priority to one's own independent opinion (ijtihad al­ra'y).

Each of these requires explanation and a detailed account, and the Shi`i­Sunni debate is relevant to such an account. Many books have been written both for and against this idea, viz., that ijtihad is on a par with textual evidence, and the best of them is the treatise written recently by the late `Allama, the Sayyid Sharaf al­Din, called "al­Nass wa l­Ijtihad".[^12] Now, according to Shi`i Muslims, such a kind of ijtihad is not permitted by the shari`a.

In the view of Shi`i Muslims and their Imams, the first basic principle of this matter, i.e., that the rulings of the Book and the Sunna are not adequate and that it is therefore necessary to practice ijtihad al­ra'y, is not correct. There are many hadiths relevant to this discussion, and, in general, [they tell us that] there exist rulings for every eventuality in the Book and the Sunna.

In "al­Kafi" [^13], after the chapter on bid`a [innovation] and maqa'is [measurements], there is a chapter with the title: "Chapter on referring to the Book and the Sunna - and there is no halal [permitted thing] or haram [forbidden thing] or anything which the people need which does not come in the Book or the Sunna." The Imams of the ahl al­bayt have been known since the earliest days as opponents of qiyas and ra'y.

Of course, the acceptance or non­acceptance of qiyas and ijtihad al­ra' y can be studied from two angles. Firstly, from the aspect from which I have looked at it; that is to say, we count qiyas and ijtihad al­ra'y as one of the sources of Islamic legislation, and place it alongside the Book and the Sunna, and say that there are cases which have not been ruled upon by revelation and which mujtahids must explain using their own opinion.