Richard Hidary's book, a revision of his NYU dissertation, tackles the topic of “practical pluralism” in rabbinic literature. It seeks to determine “whether and to what extent the ideal world of the rabbis included multiple groups, each practicing one or another variation of halakhah, or whether they wished for only one unified set of laws for all Jews” (2). The topic is challenging because it implicates, more than incidentally, an assortment of large and slippery concepts, including the nature of halakhah, the relationship between law and custom, and the possibility of multiple true, mutually exclusive halakhic positions (theoretical pluralism). To its great credit, Hidary's book finds firm footing within this quagmire, and reaches persuasive conclusions that are important both for the historian of the rabbinic movement and for the philosopher of law.

The book rests, methodologically, on comparison of parallel texts and sugyot in the Palestinian and Babylonian Talmuds. Diachronic analysis of the sugya, to clarify how it treats its sources, is reinforced by synchronic analysis, which attends to the sugya's “rhetorical drive” (39). In chapter after chapter, Hidary employs this double-edged critical method to demonstrate that the Yerushalmi assumes and/or demands unity of practice, whereas the Bavli embraces practical pluralism. While this finding is anticipated by prior scholarship, most importantly an article by Hanina Ben-Menahem that Hidary cites and critiques (13–15), the current book establishes this characteristic difference between the Talmuds more securely and generally, and contextualizes it more plausibly within the realities of the rabbinic movement in the two centers.

The first chapter focuses on rules for adjudicating tannaitic disputes. Such rules, favoring one named tanna over another, are formulated by R. Yoḥanan, the foremost Palestinian amora, and applied fairly consistently in the Yerushalmi. Though the Bavli knows of R. Yoḥanan's rules, it denies their universal (and perhaps even their general) acceptance, and feels free to flout them. This conclusion does not, by itself, unambiguously support the argument for greater pluralism in the Bavli, for to reject R. Yoḥanan's adjudication rules is not to deny that disputes must be adjudicated, or even to deny adjudication rules in principle. But disavowal of universally binding adjudication rules is compatible with and suggests an affinity for practical pluralism. Hidary contends that the greater popularity of adjudication rules in the Yerushalmi reflects in part the influence of codification efforts in contemporary Roman law, which yielded rules for deciding among competing jurists, and which have no parallel in the Sassanian context.

At the center of Chapter 2 is the rabbinic prohibition against “making factions.” In the Yerushalmi's analysis, it is assumed that the prohibition has no application in the general run of cases, because divergent, equally legitimate legal options do not, in the first place, ordinarily arise. The Bavli makes no such assumption, and radically qualifies the prohibition against “making factions” so that it does little to limit practical pluralism. This chapter also touches on law and custom in the two Talmuds. It confirms the conclusion of previous scholarship that custom carries greater weight in the Yerushalmi than in the Bavli, and allows this conclusion to inform on the issue of pluralism. By having custom hold its own against law, the Yerushalmi is able to shunt practical pluralism into the realm of custom, and thus preserve law as a monist domain. The Bavli, because it accepts practical pluralism in the legal domain itself, has less use for the category of custom.

Chapter 3 turns from law to narrative, and in particular, stories in which one rabbi visits another. Across a wide range of such stories, the Bavli projects the image of the rabbi as a local authority, whose word holds sway in his “place.” A visiting rabbi has no authority to rule against the local rabbi, though he may himself maintain his own practice. In the Yerushalmi, by contrast, there is almost no evidence of local authorities. Hidary invokes demographic and administrative factors to explain the difference. Especially in post-tannaitic Roman Palestine, the rabbinic movement was concentrated around cities in the Galilee. Rabbis were not, in general, community leaders. The Babylonian rabbinic movement, by contrast, was distributed across cities in various provinces, and appears to have superimposed itself, to a degree, on the administrative structure of the Sassanian Empire.

The division between the Houses of Shammai and Hillel is the topic of Chapter 4. Hidary finds that while “the Tannaitic sources include a variegated set of portrayals of the Houses” (166) the Talmuds select and massage their sources so that in the Yerushalmi, the positions of the House of Shammai are illegitimate (indeed, the Shammaites never practiced according to them) whereas in the Bavli, the House of Shammai acted in accordance with its positions, which are found to be more sound than those of the House of Hillel. Even the Bavli, despite its pluralist predilection, concedes that Shammaite views are no longer legitimate, but the grounds that it offers for the elevation of the House of Hillel, namely, its pleasantness and humility, nevertheless manage to further the pluralist project. “Beth Shammai's views may no longer be valid—but the Bavli still holds up Beth Hillel's tolerance toward them as a model for dealing with divergent opinions and practices in later times” (228).

In Chapter 5, Hidary examines the reception in the Talmuds of tannaitic “dissidents” who act in opposition to the majority or attempt to impose their halakhic view on others, most important among them R. Gamaliel. The Yerushalmi makes a concerted effort to establish that such dissidents did not act on their views. The Bavli makes no such effort, and is more critical than the Yerushalmi of attempts by R. Gamaliel to compel others to practice according to his view.

Chapters 6 and 7 address two conflicting sets of rules governing practice: the law of the rebellious elder, which limits the possibility of practice that diverges from the majority view, even when the latter is in error, and the laws of tractate Horayot, which, by contrast, demand that a rabbi disobey a court's decision that he knows to be erroneous. In Chapter 7 Hidary attempts to solve the tension between these bodies of law. Chapter 6, which is more germane to the book's argument, traces the rabbinic reception of the law of the rebellious elder. Tannaim transfer this issue from the judicial realm into the scholastic realm. The Yerushalmi develops the law in the same direction, while the Bavli, true to form, interprets the law almost out of existence, so that it does not threaten pluralism. The Yerushalmi, but not the Bavli, includes two stories in which one rabbi pressures another by threatening him with the label of rebellious elder.

Hidary's book does not tell us, and does not aim to tell us, whether there was, in fact, more diversity of practice in Babylonia than in Palestine. But it establishes, with admirable rigor and clarity, that rabbis in amoraic Palestine were less tolerant of such diversity than rabbis in amoraic and stammaitic Babylonia. For the amoraic period, the explanation for the difference lies, according to Hidary, in the different circumstances of the two centers: in the West, the influence of Roman codification, geographical density, and relative powerlessness among rabbis, and in the East, the absence of Zoroastrian codification, geographical dispersion, and rabbinic administrative power. In the Bavli's anonymous layer, further support for pluralism comes, for Hidary, from its academic character, which encourages diversity of opinion and, by extension, diversity of practice.

I highlight here two directions in which future scholarship might build on the book's findings. First, there is more work to do in contextualizing the divergent paths of the Talmuds against their tannaitic background. When Hidary analyzes tannaitic material, especially in Chapters 4, 5, and 6, he is often content to find variety, or a spectrum of views. Only rarely (e.g., 229–30) does the book venture to determine whether the different tannaitic positions can be made sense of as the outcome of different strains or layers within tannaitic literature. Further research might address the question: Insofar as there is tolerance for pluralism in tannaitic literature, a product of Palestine, how is it to be squared with the more systemic intolerance for pluralism in the Yerushalmi? Are urbanization and Roman law codification, both more prominent in the amoraic period, sufficient explanations, or is the story more complicated?

Second, more can be said, I venture, about pluralism and tolerance in Babylonian rabbinic culture. In Hidary's portrayal, rabbinic Babylonia emerges as a relatively irenic place. But much other scholarship finds intense competitiveness in Babylonian rabbinic circles. Is the difference a matter of amoraic versus stammaitic? Of theoretical versus practical? In historical terms, one wonders whether local authority was consistently as stable and uncontested as the sources in Chapter 3 suggest. I close with two instances from Chapter 4 that elucidate these questions. The attribution of the House of Hillel's victory to its humility should, for Hidary, be understood as a reflection of the Bavli's commitment to practical pluralism. But Jeffrey Rubenstein has instead suggested that it marks “an attempt to ameliorate the hostile environment that prevailed within the Babylonian academies.”Footnote ¹ If Rubenstein is right, practice (psak) enters here less for itself than as a rhetorical means of regulating study practice. A second strategic deployment of the rhetoric of practice arguably occurs in another source analyzed in Chapter 4 (217–19), the Bavli's portrayal of Yonatan b. Harkinas, a student of the House of Shammai. In giving him the last word, does the Bavli mean to reinforce the legitimacy of the House of Shammai, and hence, of practical pluralism, as Hidary supposes, or does the Bavli rather use this story as another opportunity to fashion a figure who is too smart for his own good, one who, like R. Eliezer, R. Meir, and Rav elsewhere in the Bavli, finds himself unable to influence practice precisely because he is unintelligible to his peers? If the latter hypothesis is correct, then in this case, too, the Bavli enlists practice rhetoric as a tool to shape academic debate. Needless to say, the considerations that I have raised detract not at all from the singularly important contributions, substantive and methodological, made by Hidary's book.