The Four Sources Hierarchy
The classical Sunni jurisprudential hierarchy:
- Quran: The primary source; all rulings are measured against it
- Sunna: The Prophet’s practice, transmitted through hadith
- Ijma’: Consensus of qualified scholars on a ruling
- Qiyas: Analogical reasoning from the above to new cases
The Hanbali school historically restricted qiyas most severely; the Hanafi school used it most expansively (alongside istihsan — juristic preference). Shia schools generally reject qiyas as a fourth source, relying instead on the Imam’s guidance; Ismaili jurisprudence similarly subjects all external reasoning to the Imam’s ta’wil.
The Structure of a Valid Qiyas
A valid analogy requires four elements:
- Al-asl (the original case): the case in the Quran or Sunna with an explicit ruling
- Al-far’ (the new case): the new situation for which a ruling is sought
- Al-hukm (the ruling): the legal judgment attached to the original case
- Al-‘illa (the effective cause): the ratio legis — the underlying reason that makes the ruling applicable; this is the critical analytical element
Example: Quran prohibits khamr (wine from grapes). New question: is palm wine prohibited? The ‘illa of the prohibition is intoxication (iskaar). Palm wine also causes intoxication — the same ‘illa applies — therefore the same ruling applies.
Controversy and Limitations
Qiyas is not unlimited. The ‘illa must be:
- Relevant to the ruling — not just any characteristic of the original case
- Transferable to the new case without change
- Not undermined by an explicit text that handles the new case differently
Scholars extensively debated which characteristics of original cases constitute the ‘illa — and the history of Islamic jurisprudence includes many disagreements rooted in different identifications of the effective cause.
See also: Ilm Al Hadith, Fiqh Al Tahara, Fiqh Al Jihad, Quran Sciences, Hikma Wisdom, Tafsir Overview