Structure and Methodology: Comparative Religion Through the Dhahiri Lens

Al-Fisal fil-Milal wal-Ahwa wan-Nihal — 'The Decisive Word on Religions, Passions, and Sects' — is Ibn Hazm's comprehensive work on comparative religion and Islamic internal theological disputes. The full title signals its scope: milal (religions with revealed foundations), ahwa (passions or deviant tendencies — used for beliefs Ibn Hazm considers incorrect but not necessarily non-Muslim), and nihal (philosophical schools and sects).

The work is organized into three broad parts. The first deals with Islamic theology and the internal debates among Muslim scholars on questions of aqeedah and fiqh. The second examines Judaism and Christianity, their scriptures, their theological positions, and Ibn Hazm's critique of their claims. The third covers other religious traditions including Zoroastrianism, pre-Islamic paganism, and various philosophical schools.

Ibn Hazm's methodological approach is explicitly and aggressively rationalist-textualist. He applies his Dhahiri principle — that legitimate religious knowledge comes only from clear textual evidence — not only within Islamic law but to his critique of other religions. For Judaism and Christianity, this means subjecting the Bible and Torah to detailed textual criticism: he identifies apparent contradictions, historical implausibilities, and what he considers logical inconsistencies within the biblical texts, arguing that these demonstrate the texts cannot be the unchanged original revelation they claim to be.

This approach to biblical criticism was remarkable for the medieval period. Ibn Hazm's engagement with the actual content of the Bible — he appears to have had access to Arabic translations — and his methodical cataloguing of its apparent inconsistencies anticipated, in a very different spirit, some of the textual critical work that would emerge in European biblical scholarship centuries later.

His treatment of Islamic theological sects follows the same pattern: he presents each position and then argues against it, usually with considerable force. The Mutazilah, the Jabriyyah, and various Sufi positions all receive his critical attention, always measured against what he considers the clear textual evidence of Quran and hadith.

The work is significantly longer and more polemical than ash-Shahrastani's Al-Milal wan-Nihal, its nearest comparable work. Where ash-Shahrastani aims for encyclopedic description, Ibn Hazm aims for decisive refutation — a difference that reflects not only personality but methodological conviction.