Usul Al-fiqh - Shi'a Law

Shi'a Law

In Shia legal theory qiyas is not recognised as a source of law. There are two interpretations of what this entails.

• According to the Akhbari view, the only sources of law are the Quran and the Hadith, and any case not explicitly covered by one of these must be regarded as not having been provided for.

• According to the majority Usuli view, it is legitimate to seek general principles by induction, in order to provide for cases not expressly provided for. This process is known as ijtihad, and 'Aql (reason) is recognised as a source of law. It differs from the Sunni qiyas in that it does not simply extend existing laws on a test of factual resemblance: it is necessary to formulate a general principle that can be rationally supported.

Javadi Amoli, in Tasnim Tafsir about source of revelation in Shiism, wrote:

1. The most important source in Shiite law is the Quran itself, which interprets itself (Quran is a kind of self commentator book)
2. The other source is the tradition of the infallibles (the family of the prophet) peace be upon them, according to the successive tradition (Saqalain) passed down by the family of the prophet (peace upon them) as well as according to the Quran itself: to accept one without the other is equivalent to rejecting both of them.
3. A third source is theoretical wisdom where it is impossible to conceive the contrary, which proves the existence of God and the necessity of his unity, eternity, pre-existence, power, will and other exalted attributes: this cannot be denied with any verse.
4. Although we cannot impose science upon the Quran, we can use verified scientific, experimental, historical, artistic, logical and other evidence to interpret the subject addressed in a given passage, rather than through another verse.

In doubtful cases the law is often derived not from substantive principles induced from existing rules, but from procedural presumptions (usul 'amaliyyah) concerning factual probability. An example is the presumption of continuity: if one knows that a given state of affairs, such as ritual purity, existed at some point in the past but one has no evidence one way or the other whether it exists now, one can presume that the situation has not changed.

The analysis of probability forms a large part of the Shiite science of usul al-fiqh, and was developed by Muhammad Baqir Behbahani (1706-1792 C.E.) and Shaykh Murtada al-Ansari (d. 1864).