Review of Aron Zysow, The Economy of Certainty: An Introduction to the Typology of Islamic Legal TheoryLockwood Press, 2013. $32.95.


By Marc Herman

University of Pennsylvania, Religious Studies[1]


Very few fields would notice the publication of a thirty-year old doctoral dissertation, let alone celebrate it. Aron Zysow’s 1984 dissertation, modestly subtitled “An Introduction to the Typology of Islamic Legal Theory,” is a remarkable exception. It is no exaggeration to say that Zysow’s contribution is the single most important work on Islamic legal theory (uṣūl al-fiqh) in any western language.

In 1984, western study of uṣūl al-fiqh was still in its infancy. Zysow therefore chose to focus on “what is typical” (2) of uṣūl al-fiqh rather than the original contribution of a given jurist. With this goal in mind, Zysow drew “the great dividing line in Islamic legal theory” between “formalist” and “materialist” legal theorists (2-3).[2] The formalists constituted the mainstream Sunni jurists who admitted probability (and therefore uncertainty) into their systems. By allowing probability, these jurists fostered what another scholar called the “normative pluralism” of medieval Sunnism.[3] According to Zysow, because the formalists were confident that they knew their legal framework with certainty,[4] they were comfortable accepting uncertainty in their legal conclusions.

The materialists, on the other hand, only accepted legal rulings arrived at by means of certain knowledge to be valid. They therefore had to limit the data that they used for legal rulings. The materialists, however, did not share a common method to achieve certainty. Some turned to an infallible Imām, while others radically limited the scope of extra-Qurʾānic traditions that they considered authoritative.

The Economy of Certainty demonstrates that the formalist-materialist divide is the central problem behind a number of ongoing debates in Islamic legal theory. Zysow did not claim that this heuristic neatly maps onto one school or another, but rather showed how jurists approached a variety of issues with the problem of certainty in mind. A careful reading of The Economy of Certainty shows that many of the Islamic schools of law (madhhab, pl. madhāhib) tolerated dissent on the question of certainty.[5]

Each chapter of The Economy of Certainty traces the formalist-materialist divide through a different topic of uṣūl al-fiqh. Chapter one examines how various thinkers approached the epistemological problems posed by the authenticity of ḥadīth. How should a jurist treat individual reports (khabar, pl. akhbār) that he cannot demonstrate originated with Muḥammad? Should he reject them entirely or can they somehow retain legal force? These and related questions divided the formalists and the materialists.

Once jurists identified the acceptable texts, chapter two addresses the jurists’ reflections on the problems of textual interpretation. Within the formalist camp, there existed a variety of positions about how confident one should be in interpreting divine texts. In recognizing linguistic problems, the formalists struggled to determine how ambiguous texts could render unambiguous legal rulings. Some formalists were skeptical that they could ever definitively interpret many texts. Unless they could identify clear textual markers, they hesitantly labeled texts that appear to be commands mere recommendations. At the other end of the spectrum, some extreme materialists rejected all post-Qurʾānic texts that required harmonization because of the associated hermeneutical problems. Their system could not countenance questionable interpretations.

In chapter three, Zysow dismissed earlier scholars who had identified consensus (ijmāʿ) as the foundation of Islamic law. Zysow showed that for the theoreticians, the basis of Islamic law was uninterrupted transmission (tawātur) of the Qurʾān and ḥadīth. Returning to his central argument, for the formalists, consensus generated certainty – something akin to prophetic revelation. The formalists believed that God guaranteed that there would remain individuals within the Islamic community who reach correct legal solutions. It therefore follows that should the jurists achieve consensus, it is necessarily correct. As analogies (which are almost always uncertain, see below) increased, this theory allowed the formalists to confirm their increasingly probabilistic system. The materialists, however, had no need to validate probabilistic solutions of the formalists, rendering consensus useless. The rejection of analogy therefore went together with the rejection of consensus.

Chapter four, then, treats the longstanding debate about the acceptability of analogy (qiyās). A classic example of legal analogy relates to the Qurʾān’s prohibition of wine. Those who accepted analogies identified the “cause” (ʿilla) of wine’s forbidden status as its power to inebriate. They therefore reasoned that other alcoholic beverages are likewise prohibited. Most supporters of analogy, however, recognized that the underlying cause of a prohibition is never known with certainty.[6] Perhaps the prohibition on wine is due to its taste or color. Those who opposed legal analogies made two claims in response: a historical argument that Muḥammad’s Companions never really accepted analogy as a basis for law and an epistemological argument that all analogy is necessarily imperfect.[7] Jurists, they argued, should treat revelation as a complete system that does not require human extension.

Chapter five considers the concept of ijtihād (lit. “exerting effort,” i.e., for the purposes of forming a legal opinion). Here, the formalist camp was divided. Some formalists who accepted the uncertain nature of law held that “every jurist is correct” (kull mujtahid muṣīb) – a slogan that attempted to account for the legal diversity of the medieval Islamic world (266). These “infallibilists,” as Zysow termed them, held that once a qualified jurist followed a valid process he could be confident that his solution was legally legitimate. His solution may not be “correct” in the sense that there exists a single answer to a legal question, but it is nevertheless legally binding because the system itself accepts probability. For other formalists, who Zysow labeled “fallibilists,” the law only recognized one correct answer. Yet they too accepted probability; they only denied that all conclusions reached by ijtihād were “correct” (265). The materialists rejected ijtihād, and thereby the entire apparatus of Sunni legal theory. They replaced it with a variety of options: divine illumination (281–82), an infallible Imām (3), or other solutions that granted certainty.

The Economy of Certainty is a difficult work even for those initiated into the basics of Islamic intellectual history. For those not yet knowledgeable about the contours of Islamic law and theology, The Economy of Certainty will undoubtedly prove challenging. Among the issues it addresses are questions of hermeneutics, theology, and logic. For those willing to read The Economy of Certainty slowly and carefully, it will prove remarkably rewarding. Zysow’s clear style and ability to categorize groups of thinkers concisely make this difficult material somewhat more accessible. Furthermore, each chapter largely stands independently; the uninitiated can digest this masterful work piece by piece.

The Economy of Certainty teaches contemporary legal theorists that the pre-modern world fostered an extraordinarily self-conscious legal theory. On many subjects, it is not difficult to place medieval Islamic legal theory in conversation with modern jurisprudence. The self-examination of the exponents of uṣūl al-fiqh testifies to their desire to reflect on the limits and problems of their project. The Economy of Certainty further illustrates that these jurists were able to construct a profound jurisprudential and metaphysical system.

For students of Jewish history, The Economy of Certainty describes a legal theory that medieval Jews in the Islamic world used to reflect on their own law. Scholars today frequently read rabbinic law in light of Anglo-American jurisprudence. Much like contemporary legal scholarship, the medieval Islamic intellectual tradition valued legal theory as an independent intellectual endeavor. Uṣūl al-fiqh left a deep impact on contemporaneous Jews, especially in the tenth and eleventh centuries.[8] These Jews – Qaraite and Rabbanite alike – used the terms and concepts of Islamic legal theory to reflect on their own legal projects. As scholars of this period continue to study just how they did this, The Economy of Certainty will prove invaluable.

[1] I thank my colleague Elias Saba for his helpful comments on this review.

[2] Throughout The Economy of Certainty, Zysow used the writings of ʿAlāʾ al-Dīn al-Samarqandī (d. 1144) and other Central Asian Ḥanafīs as the basis of “what is typical.” But The Economy of Certainty is by no means limited to examining their thought.

[3] Baber Johansen, “Truth and Validity of the Qadi’s Judgment: A Legal Debate among Muslim Sunnite Jurists from the 9th to the 13th Centuries,” Recht von de Islam 14 (1997): 3. See also idem, Contingency in a Sacred Law: Legal and Ethical Norms in Muslim Fiqh (Leiden: Brill, 1998), passim.

[4] Zysow added that once a given solution to a legal problem achieved the consensus of the jurists (ijmāʿ), it too was considered certain; see below.

[5] See, e.g., pp. 34–41. Zysow did not explicitly claim that dividing Islamic legal thought along the lines of the madhāhib is a poor heuristic, but he certainly implied it. He addressed this issue more explicitly in “Muʿtazilism and Māturīdism in Ḥanafī Legal Theory,” in Studies in Islamic Legal Theory (Leiden: Brill, 2002), 235–65. On this issue, see also A. Kevin Reinhart, Before Revelation: The Boundaries of Muslim Moral Knowledge (Albany: SUNY Press, 1995).

[6] An interesting case is when the cause has been explicitly identified in the divine text (known as al-ʿilla al-manṣūṣa); see 188–89.

[7] Zysow (160, 254) compared this criticism to Hume’s critique of induction.

[8] See David Skalre, Samuel ben Ḥofni Gaon and His Cultural World: Texts and Studies (Leiden: Brill, 1996); idem, “Yusuf al-Basir: Theological Aspects of his Halakhic Works,” in The Jews of Medieval Islam (Leiden: Brill, 1995), 249–70; and Gregor Schwarb, “Uṣūl al-fiqh im jüdischen ‘Kalám’ des 10. und 11. Jahrhunderts: Ein Überblick,” in Orient als Grenzbereich? Rabbinisches und außerrabbinisches Judentum (Wiesbaden: Harrassowitz, 2007), 77–104.


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