Analogical Reasoning Is Not a Source of Law

Qiyas, extending a known ruling to a new case on the strength of a shared underlying reason, became one of the four accepted sources of law in the Sunni schools that followed Shafii's systematic method. The Zahiri school rejected it outright. Ibn Hazm, writing in eleventh century Muslim Spain and the tradition's most systematic surviving voice, argued that qiyas asked jurists to identify the reason, the illa, behind a specific textual ruling and then apply that reason to situations scripture never actually addressed, a move he read as substituting a jurist's own guess about God's intention for what God had actually said. Mohammad Hashim Kamali's account of the classical debate over qiyas presents Ibn Hazm's alternative plainly: only the explicit wording, zahir, of the Quran and authenticated hadith, together with the consensus specifically of the Prophet's own Companions rather than later generations of scholars, could establish a ruling. Anything a case's own text did not settle stayed unsettled rather than being extended by resemblance to something it did settle, a position that left the Zahiri school with a narrower body of binding law than its analogically minded rivals, and, its adherents argued, a far more honest one.

Rejecting qiyas did not require agreeing on why it should be rejected, and three quite different traditions arrived at the same negative conclusion from separate premises. The Zahiris refused it as an illegitimate substitute for scripture's own explicit wording, trusting only what the text plainly said. Twelver Shia jurisprudence rejects qiyas for a different reason entirely: Moojan Momen's history of Twelver doctrine explains that the school relies instead on aql, disciplined rational inference from premises the tradition already holds certain, which its jurists distinguish sharply from analogy's method of reasoning by resemblance between two textual cases, arguing that the Imams' own transmitted guidance made reasoning by resemblance unnecessary where reasoning from settled premises was available. Quranism goes further than either, rejecting not only qiyas but the entire body of hadith literature that Zahiris and Twelver jurists alike still treat as authoritative alongside the Quran, leaving the text of the Quran itself as the sole source from which any ruling, by whatever method, may be drawn. The three positions share a single negative conclusion, that analogy has no place in deriving God's law, while disagreeing completely about what should be consulted in its place, which is why they are recorded here as three separate traditions holding one shared refusal rather than one shared doctrine.