Deeply familiar with Islamic as well as Jewish law, Libson argues convincingly that, in many cases, the Geonim absorbed material directly from Islamic law as custom, employing the principle of halakhic jurisprudence that custom can serve as a source of Jewish law.40 For Maimonides, Libson looks in the first instance to Shāfi‘ī law, which was prominent in Egypt even when it was ruled by the Ismā‘īlī Fatimids (969–1171), and even more so during Maimonides’ time. Libson finds Shāfi‘ī legal parallels in the Mishneh Torah as well as similarities in theoretical approach.41 While Libson’s scholarship in all these matters centers on a legal-historical reading, focusing on the influence of Islamic law on Jewish law in the realm of prescriptive texts, he properly understands the process of borrowing as a response to socioeconomic forces in the Islamic world. Central to his thesis is his taxonomy, drawing a distinction between “borrowed custom,” a custom “lifted directly from Islamic law,” and “responsive custom,” which “stemmed from the Geonim themselves in response to the general economic and existential needs of the time.”42
The present study puts primary emphasis on the economic aspect itself, foregrounding documentary evidence from the Geniza and in the responsa of economic realities in the Islamic world that are reflected in and responded to in Maimonides’ Code. Through a careful analysis of a broad selection of halakhot dealing directly or indirectly with commercial law and practice, this case study in Maimonidean codification strengthens the conclusion about the relationship between Jewish law and society arrived at through comparative legal study. At the same time, it points to an aspect of originality in the Code that has hitherto gone unnoticed.43
0.6 Islamic Legal Change
In order to situate Maimonides and his predecessors in their general intellectual milieu, it is instructive to consider what contemporary scholars of Islamic law consider to be the traditional Muslim view on legal change. Subhi Mahmassani explains that Muslim jurists place restrictions on making changes in ritual law. Concerning “worldly transactions,” however, some Muslim jurists adopt a more flexible policy. They take the context of legal rulings into account and allow for changes in the law to conform with changing circumstances.44 Summarizing the relationship between law and society, Mahmassani adds that “some caliphs, imāms, and jurists … endorsed the possibility of change in the explanation or interpretation of texts, because of a change in their causes or in the customs upon which they were based, or in answer to necessity and public interest.”45 Frank Vogel explains the situation as follows: “Practice also reveals vital aspects of law going beyond substantive doctrine, such as the workings of morality or revealed precepts outside of law and the formal legal system (in our sense) and various methods of responding to social and economic circumstances and changes without overt change of doctrine, such as contingently justified gradations, variations or exceptions in doctrine, fictions, artifices, or court procedures.”46
Hossein Modarressi notes the Qur’ānic principle that “[n]o one can change [God’s] words” but goes on to explain what he calls “the principle of discretionary judgment in Sunnī law”: “The interests of the community and individual welfare do not remain constant but rather change over time and from place to place, in accordance with changing social circumstances. The law legislated on such a changing basis must inevitably change too; and it is held to be the function of the jurists to modify the interpretation of the laws to conform with new social conditions and the requirements of the time.”47
Wael Hallaq’s view on legal change in Islam runs along a similar path. “Muslim jurists were acutely aware of both the occurrence of, and the need for, change in the law, and they articulated this awareness through such maxims as ‘the fatwā changes with changing times’ (taghayyur al-fatwā bi-taghayyur al-azmān), or through the explicit notion that the law is subject to modification according to ‘the changing of the times or to the changing conditions of society.’”48 A maxim cited in the Ottoman Meçelle (Article 39) sums this up succinctly: “There is no disputing that rules of law vary with the change in times” (lā yunkar taghayyur al-aḥkām bi-taghayyur al-azmān).49
Thus, despite the fact that custom is technically not accepted as a source of law in Islam, historically it has played an important role in legal evolution. The early nineteenth-century Ḥanafī jurist Ibn ‘Ābidīn sums up the maxim about changes in the law with changes in the times: “Since the muftī must follow custom even if it contradicts the written text in the established reports, is there a difference between general custom and special custom, as in the first part [of the treatise], that is when custom contradicts the textual rule? I say: there is no difference between them except that general custom establishes general rules and special custom establishes a special rule. In conclusion, the rule of custom applies to all people, whether custom is general or special, within general custom in all countries applying to people in all countries, whereas a custom special to one area applies only to this area.”50
The Geonim and Maimonides lived, therefore, in a society in which custom played a significant role in juristic theory and practice, especially in commercial law—the area, probably more than any other, where practice influenced legal norms. In seeking to understand Maimonides’ method of codification, it is useful to consider Wael Hallaq’s discussion of the relationship between the jurisconsult and what he calls the “author-jurist.” Hallaq proposes that the principal device effecting legal change in Islam was the fatwās (responsa) issued by muftīs (jurisconsults) and, in turn, transformed by “author-jurists” into changes in normative law.51 By the very nature of his profession, fielding questions arising from daily life, the muftī knew, better than most people, where the discrepancies between law and society lay. Maimonides, who was both a Jewish muftī, writing hundreds of responsa—muftī al-milla, “muftī of our religious community,” in the words of one Jewish seeker of legal guidance52—and at the same time an author-jurist, compiling a comprehensive code of Jewish law, belonged, therefore, to a cultural milieu shared with his Muslim counterparts.
0.7 Structure of the Book
To guide readers of this book, I present here a brief summary of its chapters. Chapter 1 discusses codification and legal change. I introduce two legal scholars who have raised the question of the relationship between the two. One of them is Maimonidean scholar, Gerald Blidstein; the other is Alan Watson, scholar of legal history and theory. Periodically in the book, I will return to these scholars, linking their views to the discussion at hand. In Chapter 1, I also review one of Maimonides’ most discussed taqqanot—a reform in the synagogue service—to demonstrate how he took daily life into account in his legal decision–making in the Code, even in the realm of ritual.
Chapter 2, “Halakha and the Custom of the Merchants,” makes the case that the Babylonian Geonim and Maimonides were attuned to the ways of the Islamicate marketplace. The Geonim called this (in Arabic) ḥukm al-tujjār, “the custom of the merchants.” I show how they accommodated merchant practice and other exigencies of the new mercantile economy with taqqanot, through their responsa, or by adopting new commercial practices, employing the legal maxim that custom can override the halakha. I include a discussion of the rabbinic concept of the “custom of the mariners,” illustrating the importance of the custom of the surrounding society for Jews, even in Talmudic times.
In contrast to the Geonim, Maimonides responded to the new commercial economy through codification. I establish the place of the custom of the merchants in the Code by closely analyzing one halakha from his Hilkhot sheluḥin ve-shutafin, “Laws of Agents and Partners.” Unlike the Geonim, Maimonides, who elsewhere freely uses the term “custom of the mariners,” does not employ the actual phrase “custom of the merchants,” a translation of the Gaonic ḥukm al-tujjār. Rather, writing in Hebrew