of the fifteenth century seems to have taken place primarily outside the universities.6 In Aragon-Catalonia, for example, Pere III “The Ceremonious” (r. 1335–1387), seeming consciously to model his court on the glorious thirteenth-century Castilian court of Alfonso X (1221–1284),7 commissioned scientific works and astronomical tables as well as scientific and philosophical translations. Pere’s son, Joan I “The Hunter” (r. 1387–1396), followed in his father’s footsteps while also favoring astrology and other divinatory arts in his court.8 Under his patronage and even under that of his somewhat less enthusiastic brother Martí (r. 1396–1410), mathematics, medicine, astrology, and astronomy flourished in Perpignan as well as in Barcelona, the commercial center of Aragon. Royal patronage by the fourteenth-century kings of Aragon led in turn to the employment of Jewish translators, instrument makers, physicians, cartographers, astrologers, and scientific craftsmen, laying the foundations for the important role Jews and conversos would play in Iberian science of that and following centuries.9
If the role of the court was conspicuous in the production of Jewish science in late medieval and early modern Iberia, the role of the city was no less so. Scientific writings in this period emerged nearly exclusively from urban centers that had attained a certain level of economic and commercial importance. In the sixteenth century, for example, most scientific texts were produced in Seville, the main port and commercial gateway for ships traveling to and from the New World. Madrid, the second most vibrant center of scientific publications at the end of the century, achieved this status precisely because Felipe II (1527–1598) made it his new capital. The urban nature of early modern Iberian science is expressed also in the social position of its practitioners, who (apart from some nobility and members of the clergy) came primarily from the urban literate strata of artisans, merchants, craftsmen, and scribes. Significantly, the overwhelming majority of scientific writings, whether or not in the field of medicine, were the work of physicians.10
Each of these factors helps explain the striking presence of Jews in fourteenth- and fifteenth-century science. The last factor is especially noteworthy, for the Jews were an almost completely urban group; indeed, Jews made up a disproportionate fraction of literate urban society. Moreover, from the early fourteenth century through the fifteenth, Jews were especially well represented in the medical profession. A third of the doctors appearing in the archives of Barcelona were Jews, though the Jewish population in that city made up no more than 5 percent of the total. The proportions were similar in the city of Valencia. In Huesca, a far smaller town where Jews comprised 10–15 percent of the population, more than half the doctors were Jews; in the years 1310 and 1311, they all were. The fifteenth century was no different.11
Patterns of scientific activity are shaped by a wide array of considerations, including the nature of scientific patronage, how society is structured, what communication networks are used to spread scientific knowledge, which institutions of learning are available, and the prevailing religious culture and its attitude to scientific investigation. Using Duran as an illustrative example, I will consider how the social milieu and intellectual and religious culture of the late medieval Iberian Jewish elite conditioned their scientific endeavors, and how, in particular, Duran’s scientific practice may have been shaped by and have itself shaped his Jewish identity.
First, a caveat: medieval science is not modern science. Not even in theory does it rest on the examination of a problem, the formulation of a falsifiable hypothesis, or the conceiving and carrying out of an accurate and isolated experiment that will either confirm or disconfirm the hypothesis. The word “scientist” itself is an artifact of the nineteenth century. Two modern terms often favored by historians of medieval science, are “philosopher-scientist” and “natural philosopher” (as in one who examines the natural world using the tools of philosophy).
Both of these terms suggest a particular approach to the study of the natural world that may misrepresent some of the motivations of Jewish astronomers, astrologers, physicians, and even mathematicians. Thus, while it may be appropriate to term the Christian scholastic Nicole Oresme a natural philosopher, it is more difficult to apply the same term to the Jew Hasdai Crescas, whose investigations of motion and critique of Aristotelian physics were not aimed in the least at learning about the natural world but rather at countering the radical philosophical tendencies he believed were undermining Jewish faith in his time. In addition, the more technological and number-reckoning sides of science, such as those involved in constructing astrolabes and quadrants and making and using astronomical tables and ephemerides, or, for that matter, professional engagement in medicine or astrological prognostication, are also excluded by the designations “philosopher-scientist” and “natural philosopher.”
Here I will instead employ the words science and scientific activity with the understanding that, depending on the context, they may indicate vastly differing levels and registers of work and study. Where possible, in order to avoid the strong associations of the word “scientist” with modern ideas of science, I will use more specific terms like astronomer, instrument maker, astrologer, physician, and so on.
The Duran-related texts examined below are by individuals whom we can place in a particular world and culture. They include letters copied and preserved outside their original context, scientific texts with marginal notations, a collection of writings by Duran put together by one of his students, and a rare example of class notes jotted down by another student. The texts are closely tied to their time and place, a part of material culture containing the physical trace of human hands as well as of a human mind.
MS PARIS BNF HÉB 1023
Our first source is a manuscript that contains approximately thirty folios of notes taken down by a student of Duran.12 Preceded by two astronomical works—a commentary on the ninth-century Elements of Astronomy by al-Farghānī (Kitāb fi-l-ḥarakāt al-samāwīya wa-jawāmiʿ ʿilm al-nujūm, a nonmathematical summary of Ptolemaic astronomy translated into Hebrew by Jacob Anatoli) and an abridgment of that same work—and followed by a selection in Hebrew translation of treatises by well-known Arabic philosophers, the notes record brief mathematical techniques: how to multiply spherical fractions, how to find a square root, and so forth, often illustrated with diagrams or examples. There are also numerous comments on how to use astronomical tables or observational instruments. Marginal notes in the student’s hand are also found on the first item in this manuscript, the commentary on al-Farghānī.
The student who recorded these notes seems to have been working from other texts, sometimes extracting passages from them. When extracts are presented, a heading notes the source and sometimes indicates whether the manuscript is in the author’s or another’s hand. For example, an anonymous commentary on the twelfth-century work on planetary astronomy by the Barcelona astronomer and astrologer Abraham bar Ḥiyya (Ḥeshbon mahalakhot ha-kokhavim [“Calculation of the Paths of the Planets”])13 is said to come from a book of Duran’s “in the handwriting of someone else,”14 suggesting that the student is extracting the glosses from a manuscript Duran himself had copied (or perhaps just purchased), and that the marginal comments are in someone else’s handwriting. Again, comments on what look to be Gersonides’ astronomical tables are said to be from a book of Bonet Bonjorn, written with “his [own] fingers.”15 Some of these constitute very brief snippets from works like Ptolemy’s Almagest, while others are longer extracts from, for example, a letter by Duran himself on the true and median conjunctions.
It is not possible to say whether these jottings were the work of days or weeks or years. The hand is the same throughout, but with sufficient deviations in ink, pen, and speed to make it clear that the notes were not copied formally and sequentially from a preexisting text but added as the material came to hand. The diagrams tend for the most part to be fitted into the text, with the words flowing around them. What we seem to be seeing is the progress of a student’s learning. While there are no explicit references to other students, sometimes the writer varies the first person singular—“a question that I asked”—with the first and third person plural—“we
