Copernicanism in the Classroom: Jesuit Natural Philosophy and Mathematics after 1633

How was the teaching of Copernicanism slotted into disciplinarily specific categories of natural philosophy and mathematics both before and after Galileo's trial in 1633? What types of questions and evidence did professors regard as being appropriate to mathematics and to philosophy? And did these change over time? The answer to the last question, of course, is yes. It has long been considered a truism that one of the key transformations wrought on early modern science was the mathematization of natural philosophy, a process which involved the entrance of mathematics into natural philosophy and its ascendancy from a utilitarian tool to one which was regarded as providing true knowledge of the physical world.[1] The aim of this contribution is to probe this accepted narrative and to see how examination of the classroom teaching of often-overlooked Jesuit professors at the Collegio Romano illuminates, enriches, or calls into question its contours. On-the-ground Jesuit teaching corroborates commonly held perceptions, namely that mathematics and natural philosophy moved closer over the course of the seventeenth century and that the Church's 1616 and 1633 decrees regarding Copernicanism and Galileo led to a hardening of certain positions, including that of the hypothetical nature of astronomical hypotheses. In other cases, classroom teaching of Copernicanism challenges accepted notions of the relationship between natural philosophy and mathematics by offering evidence of the fluid boundary between the disciplines and of the agency of natural philosophers in appropriating their mathematical colleagues' arguments. These discrepancies highlight the peculiarity of Copernicanism as a novel and condemned doctrine and suggest a revision of how contemporaries understood the Catholic Church's condemnation of the heliocentric hypothesis.Teaching Copernicanism before 1633The Collegio Romano was founded in 1551 by Ignatius Loyola (1491-1556). By the seventeenth century, it stood at the centre of a vast international network of Jesuit colleges which aimed to provide a rigorous and orthodox education that was offered free of charge. The Order's high standards of scholarship, as well as its commitment to sound and established teaching, were enforced both through an internal system of censorship and through ordinances promulgated with regularity through the period.[2] Jesuit scholars, however, had some degree of flexibility in their response to these censorship mechanisms. They could publish without the Society's imprimatur, appeal for special exceptions, or treat forbidden topics with the judicious use of terms such as true, false, and probable.[3] Thus, the fact that Jesuits discussed the Copernican system both before and after the 1616 and 1633 decrees is not in and of itself surprising.Astronomy and cosmology, the subjects dealing with the structure and motion of the heavens, were addressed in two places in the university arts curriculum. The first was in studies of philosophy, particularly in readings of Aristotle's De caelo . Related material was also taught as part of the mathematical curriculum that dealt with astronomy. The most notable of such texts used in the university curriculum were various editions of treatises titled De sphaera . They were modelled on John of Sacrobosco's thirteenth-century introduction to astronomy of the same name and detailed the conventions and definitions employed by astronomers, such as the zodiac and equinoctial circles, as well as the defining structure of the universe and the motions of the heavenly bodies contained within it.[4] At the Collegio Romano, philosophy was taught in a 3-year sequence, comprising logic, natural philosophy, and metaphysics, and was based on the writings of Aristotle. Mathematics was taught both in a year-long public lecture and privately.[5] This contribution focuses on the public teaching of both philosophy and mathematics, as evidenced in both printed textbooks and manuscript notes. …