In her insightful and engaging book, Law and Politics under the Abbasids, Sohaira Siddiqui presents an analysis of the thought of the 11th-century polymath Imam al-Ḥaramayn Abu Maʿali al-Juwayni (d. 1085). Siddiqui's study emphasizes the intertextuality of al-Juwayni's theological, legal, and political writings and argues that his work is connected by two threads: a desire for epistemic certainty on the one hand, and religious and social continuity on the other.

Law and Politics under the Abbasids is divided into four parts, and the first chapter examines the history of Nishapur, which by the 11th century had seen the waning of the Abbasid caliphate and the rise and fall of a number of ruling dynasties. The arrival of the Seljuks in 1037 upset the balance of power among the city's familial, theological, and legal groups and led to instability; and it was this instability, Siddiqui maintains, that compelled al-Juwayni to construct theoretical systems that could withstand turning political tides and societal change. Chapter 2 charts al-Juwayni's intellectual biography: from his education in Nishapur, to his travels to Baghdad and the Hijaz, and finally to his tenure as the head of the Niẓāmiyya.

The second part of the book focuses on al-Juwayni's epistemology. In Chapter 3, Siddiqui sets the scene by introducing readers to debates between the late Basran Muʿtazilis and the Ashʿaris, as represented by al-Qadi ʿAbd al-Jabbar (d. 1025) and Abu Bakr al-Baqillani (d. 1012–3), respectively. The Muʿtazilis’ belief that knowledge of moral and legal values was either innate or the direct result of speculative reasoning led to a view of law as a matter of universal recognition. The Ashʿari stance that such knowledge could only be ascertained through revelation led to a view of law as the province of specialized scholars (what Siddiqui calls the marginalization of the individual and the valorization of the jurist) whose judgments were not entirely certain (what she calls the acceptance of legal indeterminacy) (p. 106). Siddiqui writes that this afforded the Muʿtazilis a certainty in moral and legal matters that escaped their Ashʿari interlocutors.

Chapter 4 depicts al-Juwayni as a thinker who moved “beyond the legal and theological constraints he inherited from the Ashʿaris to construct a new epistemology” that could claim the same certainty as that of the Muʿtazilis (p. 10). Siddiqui explains that he accomplished this by arguing that under specific conditions, knowledge could be acquired through speculative reasoning, the repetition of actions, or the observation of customs, and that the resultant knowledge was epistemically equal to the immediate knowledge (ʿilm ḍarūrī) that a person could not disavow, such as knowledge of the self or of impossibilities like the excluded middle. As Siddiqui sees it, the “implication of this position is that reasoning individuals can reach practical certainty in the subject of their reasoning” (p. 130). Siddiqui qualifies this certainty as practical because it “cannot be universalized or equated with the ontological reality of knowledge as envisioned by the omnipotent God, but it does enable the believer to have confidence in his or her legal enactments” (p. 284). Siddiqui's line of reasoning is that as an Ashʿari, al-Juwayni did not believe that individuals could have true certainty in moral and legal matters, but he endeavored to afford them practical certainty through their use of reason and adherence to custom. Moreover, he utilized this realm of practical certainty to push back against Ashʿari legal indeterminacy and to “reject the Ashʿaris’ marginalization of the individual” (p. 130). In this way, a jurist who used speculative reasoning to arrive at a legal judgment, or a layperson who adhered to religious custom could have practical certainty in their actions.

Siddiqui's analysis offers important insight into al-Juwayni's contribution to Ashʿari epistemology and his emphasis on the social construction of knowledge, but it also raises some questions. First, what is meant by certainty, and to which concept in al-Juwayni's work does it correspond? The primacy of place granted to certainty in this study is curious given that the Ashʿaris criticized the Muʿtazili proposition that knowledge could be recognized because of the certainty or conviction (sukūn al-nafs) which it effected in the soul of the knower, and insisted that, due to its subjectivity, certainty was a deficient criterion for knowledge. Second, how can al-Juwayni's desire for practical certainty in morality and law be deduced from his enumeration of the sources and categories of knowledge? This is both a question about historical analysis (what can be read into a text) and a question about al-Juwayni's epistemology (how does the notion of practical certainty square with his insistence on divine legislative supremacy or his view of the dependence of normative judgments on revelation). Third, Siddiqui's analysis takes for granted that al-Juwayni affirmed reasoning, repetitive action, and custom as sources of knowledge, but his terms appear to be more specific. In Al-Burhan fi Usul al-Fiqh, he limited the application of speculative reasoning (naẓar) to matters that could be affirmed or negated, and he specified that knowledge could be constituted by the embodiment of technical crafts (al-ḥiraf wa ‘l-ṣināʿāt) and the observation of habitual occurrences like the external expressions of emotional states (qarāʾin al-aḥwāl). This raises the question of whether it is fair to interpret these terms more generally. Finally, taking seriously the claim that al-Juwayni rejected the marginalization of the individual requires that we ask how al-Juwayni conceived of the individual to begin with. Given the modern philosophical underpinnings of this concept, and the particularity of modern modes of subjectification, one could ask whether it was even possible for al-Juwayni to think in these terms.

The third part of the book focuses on al-Juwayni's legal theory. In Chapters 5 and 6, Siddiqui demonstrates that al-Juwayni rejected previous scholarly attempts to provide scriptural proofs for the legal sources of hadith and consensus (ijmāʿ) and instead justified them on rational grounds through recourse to custom. In the case of concurrent (mutawātir) reports, she writes, custom took the form of communal practices that attested to their once-widespread knowledge, and in the case of consensus, it took the form of juristic acceptance that indicated the existence of an early text that established its validity but was lost over time. Chapters 7 and 8 explore al-Juwayni's defense of analogical reasoning (qiyās) despite his acknowledgment that the norms and rulings derived through it were probable at best. Siddiqui sees this as the moment he “allowed his desire for continuity to trump his desire for certainty” but shows how he nevertheless attempted to limit legal pluralism by establishing a hierarchy of qiyās forms and limiting the use of qiyās to the most advanced scholars, the mufti-mujtahids (p. 185). Siddiqui's discerning analysis sheds light on al-Juwayni's unique contribution to topics in legal theory that have been more broadly studied, such as the common good (maṣlaḥa).

The fourth part of the book examines al-Juwayni's political thought and concludes that in political matters, he also sacrificed certainty for continuity. Chapter 9 summarizes al-Juwayni's exposition of the ideal imamate and his acceptance of a competent (kāfī) ruler. Chapter 10 takes up his discussion of the survival of the shariʿa in the absence of rulers and scholars through a legal minimalism that depended on individual memory of legal knowledge and collective adherence to shariʿa-based custom. Siddiqui writes that this discussion allows us to see the shariʿa as a system of governance that is socially rooted and polyvalent, as opposed to a system of government that is institutionalized and externally imposed. Even in the absence of governments, institutions, rulers, and jurists, she contends, al-Juwayni's work suggests that the shariʿa remains vital so long as it provides meaning for its followers and they remain committed to its narrative. Siddiqui concludes that al-Juwayni's work has much to offer contemporary debates about Islamic legal reform and the relationship of the shariʿa to various political configurations, among other things.

Siddiqui's effort to connect al-Juwayni's epistemology, legal theory, and political thought is truly valuable, as is her attempt to draw al-Juwayni's work into contemporary debates. It also suggests avenues for future thought. First, what is the constitutional import of al-Juwayni's view that the shariʿa occupies a place of categorical priority and what can this view offer the problematic of sovereignty as a transcendent authority that can exceed or overturn the law? Second, can a shariʿa reduced to a minimal legal corpus be meaningful? After all, as al-Juwayni acknowledged, the shariʿa survived for centuries without an ideal imam, but not without rulers who oversaw matters of war, internal order, the treasury, and the delegation of jurisdictions (judgeships, governorships, and so on). Similarly, can a shariʿa denuded of the intellectual and social organization of the madhāhib, or the communal authority of a private class of scholars, survive? It is the achievement of Law and Politics under the Abbasids that it encourages readers to confront such questions and to consider al-Juwayni's answers to them across a broad swath of his writings.