Ibn Hazm's Rejection of Reasoning by Resemblance

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.