Eli D. Clark
According to a recent survey, 56% of Americans perceive a conflict between science and religion. Orthodox Jews keenly feel this tension, as they regularly navigate between conflicting truth claims of Jewish tradition and modern science.
An early example of this conflict appears in the attempt by medieval philosophers to harmonize faith and reason. More recently, the Scientific Revolution posed new challenges to religious thought. By the end of the seventeenth century, the bedrock tenets of Aristotelian physics, Ptolemaic astronomy, and Galenic medicine were all cast into question. The Jewish response to these developments has been chronicled in several important and wide-ranging works.
In a startling new study, Tarnegolet Beli Lev: Dat U-Mada Ba-Ketivah Ha-Rabbanit Ba-Me’ah Ha-Shemoneh Esreh [A Heartless Chicken: Religion and Science in Early Modern Rabbinic Culture] (Jerusalem: Bialik Publishing, 2021) [Hebrew], Maoz Kahana explores the crisis in traditional Jewish circles engendered by the scientific discoveries of the sixteenth and seventeenth centuries. In a series of closely argued chapters, he interrogates responsa, sermons, and other rabbinic writings from the first half of the eighteenth century, scrutinizing the authors’ attitudes toward modern science and its achievements.
The story Kahana tells is not a conventional narrative of tensions between forward-thinking intellectuals and reactionary rabbis, between enlightened modernists and postmedieval obscurantists. Rather, by focusing his lens on rabbis and their internecine debates, he uncovers wildly different rabbinic attitudes regarding contemporary science, which in turn fueled furious debates on arcane halakhic issues.
Thus, on the topic that gives the book its title, the chicken without a heart, Kahana reviews a number of rabbinic responsa. An elementary principle of Halakhah categorizes such an animal as a tereifah, prohibited to be eaten. However, in the case at hand, there was ample evidence that the chicken, prior to being slaughtered, behaved as a healthy fowl. In 1709, R. Tzvi Ashkenazi (“Hakham Tzvi”), then-rabbi of Altona-Hamburg-Wandsbek, asserted that―notwithstanding the failure to find a heart in the slaughtered chicken’s thoracic cavity―the chicken was not a tereifah because “it is impossible for any worldly creature to live even one hour without a heart” (She’eilot u-Teshuvot Hakham Tzvi, no. 74). In support of this proposition, he cited passages from the Talmud, Rishonim, R. Abraham ibn Ezra, the Kuzari, Guide for the Perplexed, the Zohar, and accounts of the medical views of R. Isaac Luria, but no works of science. Despite this reliance solely on traditional, premodern Jewish sources, Hakham Tzvi’s responsum was fiercely criticized by a rival, R. Moshe Rottenberg of Altona, who accused Hakham Tzvi of resolving a halakhic question by reference to nature, an approach that he branded as heresy. In contrast, R. David Oppenheim of Prague agreed with the practical ruling of Hakham Tzvi but opposed his citation of midrashic and philosophic texts in lieu of purely halakhic sources. R. Naftali Katz of Frankfurt also supported Hakham Tzvi’s ruling, but unlike R. Oppenheim, he approved the use of Zoharic texts, asserting that the Zohar was not merely a source of ancient Jewish wisdom but a reliable source of scientific information, on a par with experimental science and classical medicine.
Analyzing the halakhic ruling of each authority, Kahana sketches their different approaches as follows: Hakham Tzvi’s view of science was fundamentally premodern, premised on medieval philosophical and kabbalistic grounds and existing in harmony with Jewish law and spirituality. R. Rottenberg saw science as an alien and heretical discipline that needed to be banished from halakhic discourse. R. Oppenheim viewed science as both a discipline and a methodology with decisive halakhic consequences and therefore rejected the introduction of philosophical and mystical texts into a halakhic responsum. At the other extreme, R. Katz elevated the Zohar to an objective source of knowledge about the world. Note too that these utterly irreconcilable views issued from rabbis who not only were contemporaries of one another, but were also products of broadly similar forms of education and social backgrounds.
How does one account for these disparate approaches to science? Kahana paints a vivid picture of the complex and often contradictory approaches to science prevalent in Europe in the early modern period, then situates his rabbinic subjects within that context. Take, for example, Hakham Tzvi’s (in)famous responsum addressing whether “a person created through the Sefer Yetzirah… is counted among the ten for matters that require ten, such as kaddish and kedushah?” (She’eilot u-Teshuvot Hakham Tzvi, no. 93). Kahana sheds needed light on the familial and cultural background of this curious text.
For Hakham Tzvi, the idea of a golem was not fantasy. According to family lore, his great-grandfather, R. Eliyahu Ba’al Shem of Chelm, created a golem. Moreover, starting in the fifteenth century and continuing through the lifetime of Hakham Tzvi, wondrous and complicated automata were being constructed―mechanical eagles and lions, clockwork humans and Greek gods. These were featured in the cabinets of curiosity (Wunderkammern) of princes and nobles and publicly displayed in royal gardens and magic shows in city squares, where throngs of people came to marvel at the clockwork contraptions.
From a Renaissance perspective, automata exemplified the human ability to imitate God’s creative powers. Many saw magic and mechanics as complementary forces. Kahana cites a telling passage from R. Joseph Solomon Delmedigo (1591-1655), a student of Galileo and an advocate for Jewish participation in the Scientific Revolution: “Ibn Ezra created a creature in the presence of Rabbenu Tam… And they say that R. Solomon ibn Gabirol created a woman and that she served him…” (Matzref le-Hokhmah, 10a). This is the intellectual and philosophical context in which Hakham Tzvi related almost nonchalantly to the creation of a golem and posited that such a creature could qualify as a full-fledged member of the Jewish nation.
Importantly, Kahana shows that early modern figures did not clearly distinguish between “science” in its modern sense and occult beliefs and practices. Leading scientists of the seventeenth century developed theories to explain the ability of witches to fly and to reproduce through relations with demons. In parallel, Kahana recounts a rabbinic debate between Maharam of Lublin and R. Yitzhak Binyamin Ashkenazi―rabbi of Berlin and of Slutzk―on whether a married woman who has relations with a demon becomes forbidden to her husband. Kav ha-Yashar, a popular mussar work by R. Tzvi Hirsch Koidonover, details an inheritance dispute involving a man who was married to and fathered children with a human wife and also with a she-demon. After his death, he bequeathed his house to his human children, but he gave the cellar to his demon-children. The case came before a religious court, which ruled that the demon-children had inheritance rights (!) but could exercise them only outside the area of human habitation.
During the period in question, many rabbinic authorities reacted to scientific advances in a predictably hostile fashion. With characteristic belligerence, Hakham Tzvi’s son, R. Jacob Emden, attacked the methods, conclusions, and practitioners of modern medicine, and he especially savaged the rabbis who based halakhic rulings on the procedures and pronouncements of physicians. He also proposed an alternative, advocating a return to an older, more established, and more reliable discipline: alchemy. This proposal seems to reinforce an image of R. Emden as a close-minded, anti-science Luddite. But Kahana points out that Sir Isaac Newton was an avid student of alchemy, as was Robert Boyle, the father of modern chemistry and originator of Boyle’s Law. University-trained physicians studied and practiced alchemy, and many royals and nobles sponsored their research, seeking advances in medical and scientific research and, if successful, instant wealth.
Moreover, alchemy had an additional feature that, for R. Emden, elevated it above modern medicine. In 1737, he asked a Jewish medical student in the newly founded University of Göttingen if the faculty included any experts in alchemy or if the university’s library contained any Hebrew volumes on alchemy. The latter request was rooted in the widely held belief that alchemy was an esoteric Jewish science dating back to biblical times. Of course, R. Emden also knew―as Christian alchemists did not―that traditional Jewish literature did not include a single text on alchemy. So he sought traces of the ancient Jewish wisdom in one of the great non-Jewish libraries of Europe.
Kahana dedicates the last two chapters of his book to R. Emden’s contemporary and archrival, R. Jonathan Eybeschutz. Like R. Emden and many of his contemporaries, R. Eybeschutz saw no tension between occult beliefs and practices and the discoveries of modern science; his engagement in writing amulets is well known. More surprising is his affirmation that Greek mythological figures such as Hercules really existed, though their powers derived from magic, not the Olympians. But unlike R. Emden, R. Eybeschutz expressed an overwhelmingly positive view of modern science. On at least two occasions, R. Eybeschutz solicited a written scientific opinion from leading professors of medicine, which he translated verbatim and incorporated into his halakhic discussion. He also invalidated a traditional Jewish practice that originated in the Testament of R. Judah he-Hasid and was codified by Rema (Yoreh De’ah 11:4): the custom of ritual slaughterers to refrain from slaughtering geese in the months of Tevet and Shevat for fear of dying, unless they ate the goose’s heart. Unable to find a scientific or rational basis for this custom, R. Eybeschutz branded it darkhei ha-emori and issued an unqualified prohibition. This bold step prefigures a similar ruling of R. Ezekiel Landau analyzed by Kahana in his previous book.
In his rabbinic writings, R. Eybeschutz demonstrated an eclectic range of interests, which included Harvey’s theory of circulation in humans, Occam’s razor, research on magnetics, the American continent and its flora and fauna, mummification methods in ancient Egypt, and Galileo’s discovery of sunspots. In his sermons, he cites Josephus and Philo in Latin and even invokes the New Testament. His extant writing contains references to lost works on mathematics, astronomy, and grammar.
Kahana rightfully dismisses Azriel Shochat’s judgment that R. Eybechutz’s love of secular disciplines anticipated the Haskalah. Besides reeking of anachronism, Shohat’s pronouncement fails to account for R. Eybeschutz’s lively interest in magic or his fundamental hostility to modern materialists who questioned the eternity of the soul. According to Kahana, R. Eybeschutz envisioned modern science as taking an honored place beside Torah wisdom, magic, other occult practices, and Kabbalah, all of which would be integrated by a single Torah luminary who is the master of these complementary disciplines. This unified vision of R. Eybeschutz finds expression in a playful and imaginative text called Sefer Meirav. It describes an ongoing dialogue between a princess named Meirav and the young women who form her retinue. The women ask Meirav questions of geometry and astronomy, language and meteorology, and Meirav gives extended responses that elicit unreserved praise and admiration from her audience. Kahana concludes that Meirav, a stand-in for R. Eybeschutz, represents Jewish wisdom, while her friends typologically represent the Gentile nations.
True to its title, A Heartless Chicken is an atypical work of intellectual Jewish history. Deeply rooted in rabbinic texts, it is also firmly anchored in general scholarship. Eschewing a linear structure or central argument, Kahana takes us on a tour of an exciting but unsettled era, when scientific discoveries were toppling millennia-old doctrines and conventions. The rabbis of the time were not central players in this drama, but they needed to assimilate these developments into their worldview and, where appropriate, integrate them into their halakhic decisions. As we have seen, some responded optimistically and others pessimistically, but in each case the response was rooted in a comprehensive religious worldview.
Kahana’s innate curiosity draws him down some fairly obscure alleyways, and readers may find some of his detours ponderous. But Kahana’s own wonder and delight shines through every page. The book also benefits from his exceptional spadework; for example, R. Eybeschutz’s Sefer Meirav was lost for almost two hundred years until Kahana found an excerpt copied into a manuscript containing a commentary to the Zohar. For a work about rabbinic literature, the bibliography is stunning in its eclecticism, featuring monographs on witch hunts and Henry More, Prague and Paracelsus, the Royal Society and Rosicrucianism, John Milton and John Donne, Umberto Eco and the Antichrist.
Periodization is the historian’s cross to bear. This volume makes a strong case that, in Jewish history, the early modern period is neither a continuation of the Middle Ages nor resolutely modern, but an era of its own: when ancient Christian enmities were waning, but the internal divisions of the modern period had yet to surface; when classical scientific conventions were crumbling, but alchemy and the occult had lost none of their luster. More generally, Kahana shows that modern Jewish history is not a relentless march toward progress and secularization. Great rabbinic figures were complex personalities, and their varied approaches to modernity reflect personal passions, intellectual curiosity, and analytical rigor. Kahana too exhibits these virtues in abundance. We can hope for no less from students of Jewish history.
 Famously, Harry A. Wolfson’s Philo: Foundations of Religious Philosophy in Judaism, Christianity and Islam (Cambridge: Harvard University Press, 1947) traces this approach back to Philo and argues for its centrality in Western religious philosophy until the seventeenth century.
 E.g., David Ruderman, Jewish Thought and Scientific Discovery in Early Modern Europe (Detroit: Wayne State University Press, 1995); Jeremy Brown, New Heavens and a New Earth: The Jewish Reception of Copernican Thought (Oxford: Oxford University Press, 2013).
 All translations are my own.
 See Maoz Kahana, Mei-Ha-Noda Be-Yehuda Le-Hatam Sofer: Halakha Ve-Hagut Le-Nokhah Etgarei Ha-Zeman [From Noda Be-Yehudah to Hatam Sofer: Halakha and Thought in Their Historical Moment] (Jerusalem: The Zalman Shazar Center for Jewish History, 2015) [Hebrew], 81-88.
 Azriel Shochat, Im Hilufei Tekufot: Reishit Ha-Haskalah Be-Yahadut Germanyah [Beginnings of the Haskalah among German Jewry] (Jerusalem, Mosad Bialik, 1960), 220, quoted by Kahana, 286.