In al-Qāḍī al-Nuʿmān’s presentation on the whole, three topics loom larger than the rest: consensus (ijmāʿ), analogy (qiyās), and legal interpretation (ijtihād). As explained above, he first wrote the work in response to a debate on the issue of ijtihād in particular, and to a treatise devoted exclusively to ijtihād that a Ḥanafī opponent had written to refute his views on the topic. One would therefore expect a focus on this issue in particular in the Ikhtilāf. In addition, however, the emphasis on ijtihād may result from the fact that it represents in a more obvious manner than some of the other hermeneutic methods he cites the subjective element involved in interpreting the law. One could say the same of qiyās. Even more than ijtihād, though, qiyās had long been the subject of intense polemics both within Sunni Islam and between Sunnis and Shiʿah. The Shiʿah had inherited numbers of reports attributed to the Imams, some of which al-Qāḍī al-Nuʿmān cites, that denounce the use of analogy in the determination of Islamic law. In some of these, the Imam Jaʿfar al-Ṣādiq is portrayed as debating Abū Ḥanīfah on the matter. While these debates appear to be anachronistic, it is likely that they date from several generations before al-Qāḍī al-Nuʿmān was writing and had grown out of intense debate on this topic in particular.
It is likely that al-Qāḍī al-Nuʿmān focuses on consensus to the extent that he does—it is the longest chapter of his work—because it is the principle most often used to exclude the Shiʿah from the pale of Islam. It was the symbol of Sunni unity, the theological doctrine that implies that the Sunni community, which is envisaged as deriving from the early Islamic community under the Prophet and the rightly guided caliphs, is the saved sect of Islam. In addition, this concept more than any other was used by proponents of the Sunni legal madhhabs as a means to exclude Shiʿi jurists from being considered in the establishment of orthodoxy and in debate over Islamic law and doctrine.48 Furthermore, the topic of consensus seems to have occupied a central concern in early works of uṣūl al-fiqh, for it appears to have been placed first in books such as al-Ṭabarī’s al-Bayān ʿan uṣūl al-aḥkām.49
Al-Qāḍī al-Nuʿmān devotes significant attention to analogy and other similar concepts because they are gap-filling tactics used to flesh out God’s legislation, and he has no need for such hermeneutic procedures because the living Imam could theoretically resolve all difficult issues immediately. The situation of the Ismaʿilis was thus quite different from that of the Sunnis, and also from that of the contemporary Twelver Shiʿah, whose Imam was in occultation and unavailable for direct consultation.
Overall, al-Qāḍī al-Nuʿmān strives to denounce Sunni hermeneutic techniques for their subjective element. When he states, at several points in the work, that they all amount to the same thing, despite their difference in labels, this is the point he is stressing. Fallible humans have no right to determine what God’s law is of their own accord, and all the probabilistic methods of interpretation that they are employing are tantamount to doing just that. Instead, jurists should determine the law by consulting the Qurʾan and the Practice of the Prophet, and they should be guided in their interpretation by the opinions of the Imams, whose authority is established by the Qurʾan itself. This is a guarantee of certainty, and deviations from this system lead to uncertainty, which is unacceptable in matters of God’s law.
Sustained polemic exchanges often have the unintended effect of making the two sides resemble each other, and Ikhtilāf uṣūl al-madhāhib, whose purpose is to refute Sunni uṣūl al-fiqh, ends up resembling Sunni manuals of uṣūl al-fiqh to a large extent, at least in formal terms. Like works in that genre, it has chapters on consensus, analogy, preference, legal interpretation (ijtihād), and submission to authority (taqlīd). A major difference between it and standard manuals of uṣūl al-fiqh is the absence of chapters devoted to the linguistic principles of interpretation of scriptural material, particularly chapters on commands and prohibition, texts of general and particular scope, indeterminate and determinate texts, abrogating and abrogated texts, and so on. This suggests that al-Qāḍī al-Nuʿmān is in agreement with much of the grammatical and linguistic interpretations of Sunni jurists, or simply that he does not see a pressing need to address those topics in his polemics.
The chapter on istidlāl (inference) shows the influence of Ẓāhirī jurisprudence in particular on al-Qāḍī al-Nuʿmān’s presentation. The chapter on taqlīd (submission to authority) has most in common with the rejecters of taqlīd such as the Ẓāhirīs, al-Ṭabarī, and al-Shāfiʿī’s student al-Muzanī, who wrote Kitāb fasād al-taqlīd. The chapter on naẓar (speculative reasoning) is not included as a chapter in extant works of uṣūl al-fiqh. The topic shows up in the epistemological postulates in the introductions to such works as al-Ṭūsī’s (d. 460/1067) al-ʿUddah, which argue that speculative reasoning can produce certainty in certain circumstances and not just probability. It is clear that al-Qāḍī al-Nuʿmān is referring to Muʿtazilah in particular in this chapter, including Ibn al-Ikhshīd in particular, and he may have had access to manuals of uṣūl al-fiqh written by Muʿtazilī scholars that included chapters devoted to naẓar.
Ikhtilāf uṣūl al-madhāhib shows the importance of Shiʿi works for shedding light on the historical development of Sunni uṣūl alfiqh. This is not only because seminal works from the tradition have been lost but also because the variety of opinion on many issues in the tradition considerably narrowed over time, and many works and ideas were suppressed, making it more difficult to reconstruct the contours of formative debate in the ninth and tenth centuries over jurisprudence and legal hermeneutics. Shiʿi authors such as al-Qāḍī al-Nuʿmān may preserve aspects of debate and sources that were later marginalized and may be more ecumenical in their description of Sunni thought than contemporary Sunni writers who represented one party in a large debate. Overall, it appears that al-Qāḍī al-Nuʿmān was drawing on manuals of uṣūl al-fiqh not only in the Shāfiʿī, Ḥanafī, and Mālikī traditions of legal study, but also from the Ẓāhirī, Jarīrī, and Muʿtazilī traditions, and of these it appears that Ẓāhirī influence was uppermost, so that, beside Ibn Ḥazm’s work al-Iḥkām fī uṣūl al-aḥkām, Ikhtilāf uṣūl al-madhāhib is the most important witness of Ẓāhirī jurisprudence in existence. Other Shiʿi sources may also provide valuable insights into the development of Sunni uṣūl al-fiqh, such as al-Shaykh al-Ṭūsī’s al-ʿUddah, al-Sharīf al-Murtaḍā’s (d. 436/1044) al-Dharīʿah ilā uṣūl al-sharīʿah, and the uṣūl al-fiqh manual of the Zaydi Imam Abū Ṭālib Yaḥyā ibn al-Ḥusayn al-Nāṭiq bi-l-Ḥaqq (d. 424/1033), al-Mujzī, and should not be overlooked in future research.
THE ENGLISH TRANSLATION
I have expended a great deal of effort to render al-Qāḍī al-Nuʿmān’s prose into intelligible and fluid English, in keeping with the goals of the Library of Arabic Literature (and recognizing that those who would like to consult the original Arabic may do so in the bilingual hardcover edition.)52
This has not been a simple task, for two main reasons. The first is the use of the technical vocabulary of law and legal hermeneutics, which I have endeavored to translate into English terms rather than retaining the Arabic words in transliteration, a procedure often followed in Western studies of Islamic law. Because of the use of the same terms in varying contexts and on occasion with slightly different meanings, it has been necessary to modify the translation of these terms to fit the context while at the same time trying to avoid changing them so much that the continuity would be lost. This is particularly difficult when al-Qāḍī al-Nuʿmān stresses a certain sense of a word in order to defeat the argument of an opponent who used the word to mean something different.
The second difficulty arises from the dialectical nature of the text.