My dissertation focuses on the meaning of optical illusions in sixteenth, seventeenth, and eighteenth century Europe. I aim to analyze how members of the Society of Jesus understood the nature of the visual process, and within it optical illusions. While the topic of optical illusions has been given some attention by historians, the main focus has been to analyze its contribution to early modern art. For instance, the tricks of mirrors and lenses provided a means for producing artwork, such as anamorphic art. Instead, in my dissertation, I focus on the broader meaning of optical illusions, particularly how they were understood beyond the context of art. The Jesuits, ardent early modern intellectuals and scientists, are one interesting subgroup to study because they were active in the broader European conversations about the meaning of optical illusions and what they suggested about the intelligibility of the natural world.
An important aspect of my dissertation is the relationship between optical illusions and magic. Oftentimes magia optica was the technical label given to optical illusions. Magia optica was, however, most often recognized as a part of “natural magic”, a subset of magic, which focused on exploring the natural, yet hidden, causes of the natural world. The sixteenth and seventeenth centuries were a particularly active period for the study of natural magic, an aspect clearly recognized by the multiple editions, printings, and translations of Magia naturalis (1555), a book by the Neapolitan Giambattista della Porta, and an important source for the reception of optical tricks in the early modern period. It will be shown in my dissertation that early modern optical tricks must be understood within a tradition of natural magic, one that began in the late-medieval period, but which was given focused attention in the fifteenth and sixteenth centuries.
Such a focus on optical illusions and natural magic will bring me into contact with the rich historiography on magic and early modern culture, and allow me to demonstrate certain gaps in its historiography. Within the history of science, Lynn Thorndike, Francis Yates, and Brian Copenhaver have variously demonstrated the contributions of magic to the formation of early modern European science. Most now recognize the ways in which the aims and practice of magic operated in tandem with important scientific developments. Among cultural historians, Keith Thomas’s Religion and the Decline of Magic has shown the ways in which a magical world was intrinsic to early modern culture, particularly with respect to religion. Notably, all of these historians successfully indicate the existence of a magical world, while at the same time recognizing the difficulty in explaining its demise. It is my contention that effective explanations for the decline of magic escape the historiography of early modern culture. My dissertation, as it focuses on the nature of optical illusions, will benefit such a gap in the literature, using optical illusions to address in part the decline of magic. In order to do this, the relationship between optics and optical illusions must be elucidated.
Within the historiography of optics, the seventeenth century is an important period. It was during this time that the scientist Johannes Kepler published his groundbreaking work, Ad Vitellionem (1604) in which he explained the visual process based upon the nature of light as well as an inverted retinal image. Many important later optical developments, such as with Descartes, Huygens, and Newton, were made with respect to the conceptual and methodological formulations of Kepler. The simultaneous developments of optics and natural magic is an interesting component, made all the more intriguing by the fact that by the eighteenth century optical magic is no longer a conceptual category. Thus, the study of optical illusions during the sixteenth, seventeenth, and eighteenth centuries will allow me to comment, in part, on the decline of magic during the early modern period as well as the scope of optics. The meaning of one of these three influences the meaning of the other, and those meanings fluctuate over time.
It should be noted that such a study may be approached in various groups during this period. Important for my study of optics and natural magic, however, is the framing of the study with respect to the Society of Jesus. Since the 1980s a generation of scholarship has turned from the so-called “warfare thesis” with the Jesuits as significant antagonizers to scientific development, toward a position which focuses on the nature and particularities of Jesuit identity. With respect to the history of science and magic, most recently the historian Mark Waddell, in his book Jesuit Science and the End of Nature’s Secrets, has traced the ways in which Jesuit theological beliefs shaped their responses to the occult. As he contends, Jesuit praxis contributed to the decline of magic because of the way in which the Jesuits imbued nature with an assumed rationality. The end result of this is that the so-called “secrets of nature”, which is another name for magic, became increasingly less significant. For my purposes, the Jesuits provide me with a group that had a fairly unified intellectual, religious, and epistemic framework, the homogeneity of which will help me trace the meaning of optical illusions among members in varying contexts.
In shaping my own dissertation, I plan to draw upon Waddell’s insights and establish a baseline idea of Jesuit ideas of optics, beyond the books that discuss optical illusions. To do this I will be looking at two of the earliest Jesuit books on optics, that of François d’Aguilon as well as Christoph Scheiner, and this amidst the contemporary discussions of Jesuit educational curriculum. Understanding the normative meaning of optics within the Order more broadly will aid me in understanding the explanations certain members provided for optical illusions. An additional section will then analyze other Catholic orders, notably the Franciscans, to establish comparisons between the Jesuits and Franciscans with respect to the nature of optics as well as optical illusions more broadly. It is believed such a comparison will help me determine the degree to which there is a Jesuit interpretation of optical illusions as well as whether there might be any patterns more broadly within Counter-Reformation Europe.
In conclusion, while the dissertation itself focuses on the nature of magia optica in its various instances among the Jesuit Order, its appeal may be recognized as connecting to a wide array of early modern historians, particularly cultural historians, historians of religion, as well as art historians. The process of defining the visual artifice was an interest of the broader culture, a culture that was increasingly marginalizing the ontological category of magic by explaining the exceptions to nature. It is within such a context that the Jesuit engagement with optical illusions provides beneficial cultural and intellectual commentary.