“The People of the Book” Muhammad called the Jews, and by the “Book” he meant the Bible. Observant Jews nowadays don’t live by the Bible, but by the Talmud—but how long has that been the case? When did Jews start to live by the complex regulations of the Talmud; when did its regimen achieve its decisive hold? In brief, when did the reign of the Talmud begin?
Talya Fishman’s new study on this central issue has awakened wide interest and received high honors. Last year, the Jewish Book Council gave Becoming the People of the Talmud: Oral Torah as Written Tradition in Medieval Jewish Culture its prestigious Nahum M. Sarna Memorial National Jewish Book Award for Scholarship. The book is gracefully written, heavily documented, and advances a revolutionary argument. In fact, it challenges every notion of the past millennium about this fundamental problem and, by implication, overturns many of the most basic assumptions about the history of halakhah.
The standard version of when, where, and how the Talmud attained its normative standing runs like this: Sometime between the years 600 and 725 C.E. a group of mostly anonymous scholars known as savoraim collected and edited a vast number of the halakhic discussions that had taken place in the rabbinic academies of Mesopotamia from 200 until the middle of the 5th century. The result was the Babylonian Talmud (the Bavli). Parallel halakhic discussions had taken place in Palestine that eventuated in a Palestinian Talmud (the Yerushalmi). As Palestine was in the Byzantine Empire and Mesopotamia in the Sassanian one, the two different compendia scarcely competed. But when the Muslim conquest in the 7th century united these two worlds, the authority of the caliphs stretched from Persia to the Pyrenees, and struggles between the heads of the Palestinian academies and those of Babylonia for hegemony took on sudden urgency.
This was intensified by the rise of Jewish communities in Egypt, North Africa, and Spain that sought to take advantage of the economic opportunities of the new and vast empire. By 800-825 C.E. the supremacy of the Babylonian Talmud was assured. It became known simply as the Talmud, whose rulings were accepted as normative by Jews throughout the Muslim world (some ninety percent of the Jewish population of the time). The heads of the rabbinical academies in Mesopotamia, the geonim, became the acknowledged religious arbiters for the Jewish communities under Islamic rule.
The Talmud’s authority spread more slowly in the tiny Jewish communities of Christian Europe. By the time the Ashkenazic community emerged in the late 10th century, the primacy of the Babylonian Talmud was generally accepted there as well, though it was not firmly ensconced until the mid-11th century. Rashi, who died in 1105 C.E., provided the great commentary that made the Talmud more accessible than it had ever been. The Talmud was already normative, but it was (and is) a difficult, abrupt, and in places almost telegraphic text. Its main points are stated, but the linkage of the various points, the flow, is left up to the reader to reconstruct. It is this linkage and flow that Rashi succinctly supplied. With a word or two, Rashi gave a clarity and tightness to the talmudic argument. Each discussion of the Talmud possessed now an unprecedented lucidity.
Nonetheless, the Talmud remained a vast, loosely organized corpus with many overlapping discussions. The tosafists, the great Franco-German glossators of the two centuries following Rashi, undertook the massive project of collating all of the talmudic discussions on a given issue, noting any contradictions among them, and resolving them in good dialectical fashion by distinguishing between two apparently similar cases or seemingly identical legal terms. The founder of the tosafist movement, the man who restored dialectic to the prominent place in halakhah that it had occupied in talmudic times, was Rashi’s grandson, R. Jacob ben Meir, known more commonly as Rabbenu Tam, who died in 1171. He ranged freely over the entire Talmud and revolutionized all that he touched; he left, however, little written record of his thoughts. His teachings were preserved by his nephew, Rabbi Isaac, also known as Ri, who, together with his pupils, proceeded to subject every line of the Talmud to relentless, dialectical inquisition. The upshot of the far-ranging analyses in Ri’s yeshiva in Dampierre, a tiny hamlet in Champagne, was inscribed by his disciples, and entitled simply “Tosafot” (“additions” [to Rashi]). The Tosafot swiftly spread throughout the diaspora and shaped decisively all subsequent halakhic thought, both in substance and in method. A somewhat abridged version of these glosses has been printed alongside every edition of the Talmud since the 1520s.
The revised version of Professor Fishman will have little to none of this. Drawing upon the writings of the past generation of medievalists, most prominently, Michael Clanchy, Mary Carruthers, and Brian Stock, Fishman sketches the cultural transformation of Western Europe as its society shifted from orality to literacy. The making of records, for instance, “was actually viewed with distrust in 10th– and 11th-century England; written proof would only be demanded of someone who had fallen under suspicion.” During these centuries, the assumption was that “a witness giving oral testimony possessed greater credibility than any written document. By the 12th century, however, greater authority was ascribed to the written word.” The revival of jurisprudence in the 12th century and the rise of canon law, would, Fishman writes, also “seem to be manifestations of the textualization process.” This transformation went well beyond the narrow confines of the law courts and affected European governmental administration and the social hierarchy. Models of leadership both in the civic and ecclesiastical realms were transformed; charismatic figures, “living repositories of tradition” were replaced by “literate professional administrators.” Most importantly, Fishman writes:
As texts came to be construed as reference points for everyday activities, bodies of tradition that were once transmitted exclusively through practice . . . underwent inscription in edited compilations. People not only allowed texts to inform and shape their experiences, they sought to bring their lives into congruence with them.
The halakhah in Northern Europe, Fishman claims, followed roughly the same path. The Talmud became normative only in the course of the 12th and 13th centuries, a corollary of the same textualization process, and the leaders of the inscriptive movement were the tosafists. Geonic rulings had never been viewed as authoritative; they had been seen simply as “opinions.” The text of the Talmud was seen as an open book, especially in Ashkenaz, as scribes added to and subtracted from the text at will, much as the medieval sagas and romances took on varied forms as a result of the inspiration of differing bards or the wishes of imaginative copyists. It was the tosafists who closed the book of the Talmud, and made the Jews its people.
Fishman concedes that the tosafists did engage in some dialectic; however, their major enterprise was in fixing the fluid talmudic text and, being master collectors of texts excelling in the art of “textual rectification.” They were not theoretically oriented, but were profoundly practical men. They sought to regulate the religious life of the Jews through the text that they had stabilized and succeeded in their endeavor by authoring a dense series of written instructions, issuing practical codes and detailed handbooks, which summarized the upshot of the newly fixed talmudic discussions.
This is a radical thesis, to put it mildly. It is also formulated simply and clearly. Fishman states modestly in the introduction that she is neither a medievalist nor a Talmud scholar and in both areas has drawn primarily on secondary works. “Any new perspectives set forth in this book,” she writes “are not the fruit of pioneering archival research, but of thinking about known data in a fresh light . . . by bringing together works of scholarship from disparate fields.” There is, however, a difference in the use that she has made of these secondary sources. With regard to European history she is reporting and synthesizing what scholars have written; in Jewish history she is seeking to entirely transform our understanding of the era, indeed, not simply the two centuries of the tosafists but also some three hundred years of prior geonic activity (750-1050 C.E.). One may wonder whether a creative reading of secondary works is likely to yield insights true and deep enough to revolutionize a field. Can one revolutionize subjects that one doesn’t truly know first-hand?
Even if one should answer that question in the affirmative, one might still suggest that a basic familiarity with the primary sources is necessary to read the secondary sources with some discrimination. It may be necessary, at times, in order to recognize a patent exaggeration, as scholars advancing new ideas occasionally overstate the case. It may equally be needed simply to save oneself from drawing a seemingly reasonable inference from a secondary source, but one so outlandish to anyone in the know that the writer never thought there was any need to preclude it. Second-hand revolutions are a tricky business.
To get a sense not of Dr. Fishman’s command of the Talmud and medieval rabbinic literature—to that she has placed a diffident disclaimer—but simply of her basic familiarity with these writings, especially that of the tosafists, whose oeuvre constitutes a major crux of her argument, let us examine a few representative claims in her book. In describing the tosafists’ curriculum, Fishman writes:
Because the tosafists viewed the Talmud as a guide to applied law, talmudic passages pertaining to the sacrificial cult or purity practices that could not be practiced in the Temple’s absence were not studied in their rabbinic academies.
This is an astonishing statement. The standard editions of the Talmud ever since the 1520s have the full Tosafot on Zevachim, Menachot, Bekhorot, Arakhin, Temurah, Me’ilah, Keritut, Nazir, and Sotah. All nine tractates are devoted to the “sacrificial cult” of the Temple. Seventy percent of Yoma and thirty percent of Pesachim are occupied wholly with the Temple service. They too have a full complement of Tosafot. There are hundreds of passages in the other tractates of the Talmud that treat sacrificial laws and those of purity. All are treated exhaustively by the Tosafot (whose analyses reflect the discussions in their rabbinic academies), as a glance at almost any volume of the Talmud will evince.
The issue is not familiarity with the substance of the above-mentioned tractates, but simply familiarity with the standard format of the printed Talmud. Given the relentless collation by the tosafists of all parallel passages in the Talmud, no student can escape using these volumes continuously. In fact, the standard equipment of any Talmud student is a small format edition of the Babylonian Talmud that he (and increasingly, in certain circles, she) can put on his desk so that he doesn’t have to constantly jump up to pull a heavy tome from the shelf of the beit midrash (study hall) to check yet another three-line talmudic citation of Tosafot. Some pupils learn more, others less; but every student knows one thing: all the pages of the Talmud are the same; they all have Rashi on the inside and Tosafot on the outside. (Actually, one of the thirty-six tractates of the Talmud, a practical one, dealing with vows—Nedarim—has only the thinnest of Tosafot for reasons unknown. What’s on the “outside” is a commentary of a medieval Catalonian dialectician, R. Nissim of Barcelona.)
This lack of familiarity with the printed page of the Talmud is equally reflected in the author’s discussion of the talmudic commentary attributed to Rabbenu Gershom. Fishman draws on it for evidence of the nature of talmudic studies in Ashkenaz prior to Rashi. In a note, she writes: “Inasmuch as the commentary was supplanted by that of Rashi, it is now found only in tractates that lack Rashi’s commentary on the Talmud.” In fact, we have this commentary on nine tractates, seven of which have Rashi’s commentary. All seven are found—together with Rashi—on the printed page of the now standard Romm edition of the Talmud, which first appeared in Vilna in 1881, and has been the only readily available edition of the Talmud for the last sixty years.
Fishman also writes, “the tosafists’ mimicry of the Talmud’s language and style was so convincing that later scholars portrayed them as amoraim redivivus” [sic]. The thought of the tosafists is, indeed, an extension of the dialectics of the Talmud, but their “language and style” is another matter. The Talmud is written in pure Aramaic with citations in classical mishnaic Hebrew, the two languages being kept strictly apart, as would be the two languages in a work in English that contained French citations. The Tosafot are written in rabbinic Hebrew, which is a blend of Hebrew and Aramaic. More important, the syntax of the two languages is different. The syntax of Aramaic (and mishnaic Hebrew) is Semitic; that of rabbinic Hebrew, European. Suppose you had a text written in English with sentences as “He gave it to him,” while the massive gloss on that text was written in an English-French patois with French syntax, regularly exhibiting such sentences as “He it to him donne.” Could anyone who has studied those linked texts for so much as a fortnight write that one convincingly mimics the language of the other? As for “style”: the style of the Talmud is dialogic, as in the works of Plato; the style of the Tosafot is the impersonal, scholastic one of “Objection: . . . Reply: . . . ” as in the writings of Aquinas. When Tchernovitz and Urbach (the author’s footnoted sources for this assertion) observed, in Fishman’s words, “that the comments of the tosafists might have been mistaken for a part of the Gemara itself had they not been separated spatially from the body of that text,” they were referring to dialectical thinking of the Tosafot, which does mimic that of the Talmud, not their language or style. They were relying upon the reader’s basic familiarity with Talmud and Tosafot (such as would be acquired, as a matter of course, in a cheder) to construe their words correctly.
The above examples are unfortunately symptomatic of the entire work. Essential components of Fishman’s argument are based on statements that run contrary to the most elementary facts. One cannot help wondering whether the author, a well-regarded historian of early modern Jewish history, has ever seriously studied Tosafot, or indeed, has a meaningful acquaintance with any rabbinic sources. (And I emphasize that I am referring to acquaintance, not command of these texts.) Take her central claim that the tosafists focused on the concrete applications of talmudic law, on turning the abstract formulations of the Talmud into a halakhic regimen, that they were preoccupied with the practical and that they “viewed the Talmud as a guide to applied law.”—You would never know this from their writings. There are hundreds of controversies in any sizeable tractate of Talmud. On some five or ten occasions, Tosafot may remark, usually in passing, as to their view of the final ruling. There is not a word about the upshot of all the rest of the controversies in the tractate. Worse yet, Tosafot will very often offer several different solutions to a problem, each eventuating in a different halakhic ruling. I do not recall a single instance where Tosafot ever informs the reader which of the several doctrines proffered is the controlling one (the pesak halakhah). One can study Tosafot for decades and never have the slightest inkling what the final holding is in the thousands of issues that one has so long and lovingly examined.
To be sure, after the tosafist revolution of the 12th century had been completed and the vast corpus of the Talmud reinterpreted, several tosafists of the next century wishing to spell out the practical consequences of that revolution composed codes, or what they thought were codes. The two most famous ones (Sefer ha-Terumah and Sefer Mitzvot Gadol) rapidly got bogged down in long dialectical discussions. It was not until the end of the tosafist period, in the closing decades of the 13th century, that a practical guide to conduct, a straight series of do’s and don’ts, finally issued forth from the ranks of the tosafists in the form of the Sefer Mitzvot Katan.
The same troubling impression is made by Fishman’s second crucial characterization of the tosafists: their preoccupation with textual variants. She stresses their archival work in seeking out different versions of the talmudic text, their “textual rectification” and finally their historic importance of fixing, once and for all, the text of the Talmud that enabled its becoming normative for the first time in Jewish history. This characterization too goes against the elementary facts.
I doubt if three percent of the Tosafot treat textual matters. The majority of such instances are citations of differing versions from a North African source (Rabbenu Hananel) for the purpose of resolving a contradiction in the Talmud or variants that suggest a different interpretation of a passage. The tosafists pursued no “intense archival research,” engaged in no “archival undertakings”; they edited no text, fixed no text; they were first and foremost dialecticians and exegetes, and this is evident on every single page of the printed Talmud. Ask any day school graduate, and he or she will tell you the same.
For Fishman’s thesis to have any purchase, for it simply to get off the ground, she must first dispose of an obvious, fundamental problem. If, as she claims, the Talmud was not normative until the labor of the tosafists in Europe in the 12th and 13th centuries, why then were the thousands of queries to which the Babylonian geonim (750-1038 C.E.) responded ever penned to begin with? Why were business deals in Kairouan (a major city in North Africa) or Fustat (ancient Cairo) placed on hold, planned marriage contracts frozen, people not knowing whether they were divorced or not, all anxiously waiting for months until a ship wended its way to Baghdad with an inquiry, waited, at times weeks, at times months, for a reply which then had to make its long way home? It is the thousands of geonic responsa—Robert Brody assesses their number between five thousand and ten thousand—that form the basic building blocks of the standard version of the reception history of the Talmud. It is this vast mass of written inquiries that seems to attest to the acceptance of the normative standing of the Talmud by the beginning of the 9th century, if not somewhat earlier.
Fishman devotes an entire chapter to the geonim, discusses a number of things, but never addresses this central question. Two pages before the end of the chapter she gets around to discussing responsa and casually makes a revolutionary claim, invoking for support the writings of the two eminent scholars, Robert Brody and Berachyahu Lifshitz. She cites an article by Lifshitz, who stated, in Fishman’s words, that “the responsum, through the end of the geonic period, was not a legal verdict, but ‘merely’ a legal opinion, though, to be sure, one voiced by a person of considerable authority.” If one checks the reference given, one sees that Lifshitz was actually characterizing the position of a 15th-century Algerian scholar and “scholars who preceded him,” which Dr. Fishman rather liberally interprets as going back some seven hundred years. One might perhaps quibble with my narrow construction of his words. However, Lifshitz specifically excluded the responsa of the talmudic and geonic period from this characterization. At the outset of the article, he states that the responsa of the scholars of the Talmud (amoraim) and those of the geonim were “like the decisions of the Supreme Court”—the exact opposite of Fishman’s contention. The very next sentence after the one to which Fishman refers reads: “This fundamental difference between the nature of the responsum in the mishnaic, talmudic, and geonic period and the nature of the responsum in subsequent eras is fundamental for any proper comprehension of the place of the responsum in Jewish law.”
Fishman next adduces a passage by Robert Brody who described responsa as documents that occupied “a sort of no man’s land between the realms of literary, historical, and administrative documents.” Brody’s words are a passing remark characterizing the responsum as a genre of writing that is reactive and of limited scope, like a letter, rather than proactive like a monograph by an author who is free to determine its scope. No such comparison to literary or administrative documents appears in his chapter on the geonic responsa or in his discussion of geonic authority. In no place does he assert that the geonim did not view their responsa as halakhically binding or that the vast majority of Jews in the diaspora did not think likewise. His entire book on the geonim, as the other works on the geonic period from which Fishman cites snippets, posit the normative role of the Talmud from the 9th century onward and the authority that flowed to the geonim from their role as exclusive interpreters of this hegemonic text. In other words, there is no evidence whatsoever that the Jews did not become the People of the Talmud during the geonic period, as the standard version has had it for close to a millennium.
This pattern of selective quotation repeats itself, unfortunately, throughout Becoming the People of the Talmud. The secondary sources have not been “read” and absorbed, but skimmed or rifled though, as it were, for phrases that can be cited—as often as not, out of context—for proof of central contentions.
Fishman contends that the tosafists “felt that the most correct formulation of the talmudic text had yet to be identified” and they “propelled the process of textual rectification into high gear.” She further speaks of “both the ability of the tosafists to improve on the accuracy of the Talmud’s formulation and their drive to do so.” If this were true, there would be radical differences between the talmudic manuscripts of Ashkenaz and those of other Jewish communities of the diaspora. There is no lack of manuscripts of the Talmud, and most of their differences with the standard text have been printed and available to scholars for over a century and a quarter in the fourteen-volume Dikdukei Soferim. The differences are, as any serious student of the Talmud knows, minor, if not minute. An argument might be made that they were influenced by the tosafists. (In point of fact, some are, others aren’t.) There are, however, close to two thousand pages or fragments of pages in the Cairo Geniza, most of which antedate the tosafists, and while far from all have been scrutinized, the many that have diverge scarcely more from the standard text than do the manuscripts.
Indeed, the so-called “Ashkenazic text” of the Talmud (the one Fishman maintains was systematically emended and improved by tosafist lights) has been now found in a number of such old Geniza fragments, and this alleged “rectified,” tosafist version, the product of their unique and “intense archival research,” appears equally in Yemenite manuscripts that are free of any Ashkenazic influence! This led researchers of the past generation to conclude that the entire concept of an “Ashkenazic version of the Talmud” is mistaken. The two versions commonly associated with Ashkenaz and Spain originated in the East in the early stages of the inscription of the Talmud, probably sometime before the mid-8th century. Ashkenaz simply received one version, Spain the other. This has been a scholarly commonplace for at least a decade. Nothing of this is reported in Becoming the People of the Talmud, and for good reason. The conclusion is ineluctable. If the text of the Talmud had been fixed in the Near East some 350 years before the tosafists, then the tosafists had nothing to fix.
The “textualizaton” of the Talmud by the tosafists, their improving upon and finalizing the hitherto fluid text, and their turning that corpus into the normative text of Judaism is then a figment of the author’s imagination. All this occurred centuries before the tosafists, and on a different continent. To close the circle, I would add that the entire notion of orality in pre-tosafist Ashkenaz, which is developed by Fishman as a contrasting backdrop to the new ‘textuality’ of the tosafists, is without foundation and would never be advanced by someone who has a first-hand familiarity with the sources of that period.
What is true of the major argument of the book is equally true of many of its casual determinations. Readers, especially those from other fields seeking a guide to medieval rabbinica, should be careful in relying upon the statements contained in Becoming the People of the Talmud, as a considerable number of them are simply groundless. To give an example for which I perhaps bear some responsibility, Fishman writes:
As texts came to structure all aspects of experience, arenas of life that had only been lightly regulated—like mourning and charity—were now subject to dense and systematic written guidance.
No more, no less. To document her claim about mourning she writes:
Thus, for example, Rabbi Meir of Rothenburg composed a treatise on the laws of mourning in the 13th century in order to supplement the sparse regulation of behavior in the talmudic tractate of Semachot. Soloveitchik Ha-Yayin, 129.
Before examining this little argument, let me enter a general caveat to the reader. My work is cited elsewhere in the book as well, and I am thanked for reading a draft of one chapter in the acknowledgements. Based upon my reading several years ago of what would become Chapter 4 of the present work, I strongly urged Dr. Fishman at that time not to publish and further informed her that as her writing would mislead English-speaking readers, most of whom know nothing about rabbinics, if she went ahead with publication, I would feel obligated to review the book.
Now let us return to Fishman’s argument about the halakhic regulation of mourning. First, the laws regulating mourning that were operative in Ashkenaz (or anywhere else in the diaspora) did not derive from Semachot (a non-canonical tractate of Palestinian origin and of questionable date), but from the talmudic tractate Mo’ed Katan, and the regulations found there are far from sparse. Maimonides codified them, and they run to no fewer than twelve full chapters in his Mishneh Torah, fifty percent more than the eight chapters that constitute the laws of Passover in that code. Having discovered from a footnote of mine that R. Meir of Rothenburg authored a treatise on mourning, Dr. Fishman likely never opened that work. Had she done so, she would have immediately seen the innumerable references to Mo’ed Katan. If the author does not know where the laws of mourning are found in the Talmud, she has no familiarity with the commentaries and commentary-codes on that subject. She cannot then know whether or not there was an abundance of mourning regulation in Ashkenaz prior to R. Meir of Rothenburg, especially, as she seems never to have checked the responsa literature. Simply looking at the table of contents of Rashi’s responsa would have shown her that there are as many responsa on mourning as there are on usury and money lending.
As to her mode of inference from my study, one cannot help asking: what does the date of Rabbi Meir of Rothenburg’s treatise prove? The only line of historical reasoning that I can imagine is that since a separate work on mourning is first composed in the 13th century, this proves that prior to this time, mourning was “lightly regulated.” Seeing that the first separate treatise on circumcision is of the same date, are we then to infer that prior to that time circumcision was “lightly regulated”? As no separate treatise on the laws of Rosh Hashanah and Yom Kippur was ever composed in the Middle Ages—indeed, I am unaware of any such work until some fifty years ago—we can only conclude that shofar-blowing and fasting have been lightly regulated for the past millennium.
The problematic relationship between claim and documentation reflected in this citation runs through much of the book. I was repeatedly baffled how an elementary bibliographical fact or a conventional phrase in a rabbinic source could be seen as justifying the startling pronouncements made in the text. Being a compulsive note-checker, I looked up the documentation provided for many of the determinations in the book. Often I could not discern how the footnote and text were related not only in the important passages that advanced the author’s thesis, but also in places where a proper reading of the source would in no way have affected the book’s argument. I spent considerable time trying to reconstruct Dr. Fishman’s thinking, to see where and how she went astray in understanding the sources, until I realized that misunderstanding requires partial understanding. If this fractional comprehension is lacking, there are no parameters limiting the interpretation; the meaning of the source will then be whatever the writer wishes it to mean, or, absent this bias, whatever comes to mind.
A work of this sort usually needs little review; a brief notice in a scholarly journal and it sinks under the weight of its own insufficiencies. And so I thought when I read Becoming the People of the Talmud with bewilderment upon its appearance last spring. Instead—as I noted at the outset—it received the Jewish Book Council’s prestigious Nahum M. Sarna Memorial National Jewish Book Award for Scholarship, one that has been given in recent years to Moshe Idel, Elliot Wolfson, and Dan Miron. The most charitable construction that can be put on the award is that the committee never read the book. It is also possible that its members (whose identities are not made public) know even less of rabbinics than does the recipient. Both accounts leave unexplained, however, why a committee would give an award to a book that it had not read, or, alternatively, why a committee would bestow an award upon a book in a field about which it knows nothing.
Nahum M. Sarna, the outstanding scholar whose name graces the prize the Jewish Book Council awarded, was a biblicist, however, like one or two other academicians of the past generation, he had a deep familiarity with the entire classical Jewish literature. His memory deserves better, as does Jewish studies.
Erika Dreifus expresses dismay over Amy Newman Smith's essay on Holocaust fiction.
Eleven years and four books on, can Birthright Israel save diaspora Judaism?
“I wanted to write an integrated history,” Saul Friedländer told a magazine in 2007, in an interview marking the long-awaited concluding installment of his Holocaust study Nazi Germany and the Jews. By “integrated history,” Friedländer meant one in which the designs of genocidal perpetrators were fused with the personal testimony of the victims. “Business-as-usual history flattens the interpretation of mass…
Leora Batnitzky's new book charts the development of modern Jewish thought.