The Jesuits’ struggles with uncertainty came at a time when natural philosophers across Europe found themselves wrestling with the stubborn intransigence of Nature, with its refusal to reveal its secrets to their collective gaze. Nowhere was this struggle more obvious, or more freighted with anxiety, than in the study of insensible causes. Almost everyone accepted that the natural world overflowed with unseen phenomena and causes, from the invisible power of the lodestone to the mysterious forces deep within the Earth that produced earthquakes and volcanism. Where and how such phenomena became manifest to the gaze of early modern naturalists—and their implications for theology, philosophy, and early modern culture more broadly—consequently became the central questions of the age.
On its own, the problem of insensibility raised inevitable concerns about the utility and fallibility of the senses. Insensible, but seemingly natural events posed a conflict with the empirical mode of knowing embraced first by Aristotelian philosophy and, later, by proponents of the “new philosophies.” These debates about certainty, probabilism, and vision characterized what I call the crisis of certainty. In its broadest terms, this crisis embodied the widespread rise of skeptical inquiry throughout the sixteenth century, which led many thinkers to abandon the quest for certainty and to embrace instead various kinds of probabilism. For the ancients, skepticism had been a response to dogmatism (the claim that one could and did know some truth about how things really are) and generally fell into two main camps: the Academic skepticism that originated in the Platonic Academy held that knowledge was simply unattainable, while the Pyrrhonian skepticism advocated by Sextus Empiricus and others posited that, without sufficient evidence to indicate whether attaining knowledge was possible, one should stop short of the position taken by the Academics and instead merely suspend any and all questions concerning the pursuit of knowledge.1
The Academic skeptics in particular went to great lengths to demonstrate why dogmatic statements of truth were inherently flawed: because knowledge about the world inevitably includes claims that transcend simple empiricism or observation, all knowledge must depend either on sense-impressions or reasoning, and because either or both could be unreliable, we can never have a guarantee of true knowledge.2 This was a particularly unsettling line of inquiry for many early modern philosophers. Francis Bacon, for example, inveighed against it in his 1609 Redargutio philosophorum when he said, “This Academic school, which avowedly held [the doctrine of] Acatalepsy, has damned humankind to perpetual shadows.”3 “Acatalepsy” was a philosophical doctrine held by many ancient skeptics, defined by Ephraim Chambers in his Cyclopaedia of 1728 as “the Impossibility of comprehending or conceiving a thing, [or the idea that] all human Science and Knowledge … went no further than to Appearances or Verisimilitude.”4 For Bacon, as for many of his contemporaries in the seventeenth century, this was a radical position that, if adopted, would only damage the pursuit of natural philosophy: claims that knowledge was simply unattainable seemed guaranteed to put a halt to the investigation of nature.
By contrast, ancient followers of Pyrrhonian skepticism had seen it as the path to quietude, a state of mind in which one suspended judgment on anything and everything beyond the appearances of things.5 When Renaissance humanists translated the writings of Sextus Empiricus in the sixteenth century, it was Pyrrhonianism that attracted the attention of a range of thinkers, who saw in its judicious refusal to accommodate dogmatism a new way of studying and understanding the natural world. This did not mean that more extreme forms of Pyrrhonianism did not exist as well, and even the more moderate positions of Pyrrho and Empiricus sometimes led to conclusions as destructive to the pursuit of knowledge as anything proposed by the Academics. Thus, as the pendulum swung away from the Peripatetic philosophy still taught in the universities, some thinkers saw the need for a via media, a middle way that lay somewhere between the destructive consequences of extreme skepticism on the one hand and the increasingly untenable dogmatism of the schools on the other. Marin Mersenne (1588–1648), the Jesuit-educated mathematician and Minim friar, argued for a mitigated skepticism, a more constructive path that allowed for probable claims based on observation and experience. It was a lesser form of knowledge by Peripatetic standards but one that, for Mersenne, was at least attainable.6
The movement towards probabilism led increasing numbers of thinkers to believe that repeated inquiries conducted by connected groups of naturalists could, in time, produce knowledge about the world that remained likely but that was also subject to verification and testing. Though not “certain,” these knowledge-claims were nonetheless highly probable, far more so than mere opinion or conjecture. Collaborations between naturalists became institutionalized in bodies like the Royal Society of London, the Accademia del Cimento in Florence, and the Académie Royale des Sciences in Paris, while increasingly complex networks of correspondence allowed individuals to exchange information about experiments and discoveries across national as well as confessional boundaries. Cooperative inquiry into nature became the cornerstone of the “new science” that emerged in the seventeenth century, permitting the accumulation of probable claims that slowly became the standard whereby knowledge was judged.7
The development of novel methods for studying nature did not lack for complications. As one example, the founders of the Royal Society in England attempted to walk a fine line between acknowledging the potential deceit and fallibility of the senses on the one hand and, on the other, utilizing sensory experience in the study of nature. They accomplished this in part by conscripting others to act as witnesses to specific demonstrations, echoing the increasingly collaborative nature of early modern natural philosophy. Fallibility became less of a concern as greater numbers of eyes were called upon to observe and interpret experimental results, and the testimony of witnesses was supported by contemporary standards of conduct and honesty as embodied in the figure of the gentleman-virtuoso.8 For all the ingenuity displayed by those who sought to bring reason to bear on sense-experiences—the “Descent of Reason upon the short Testimony of Sense,” as they put it—the English virtuosi nonetheless reconciled themselves to the idea that, while they could describe the appearances of natural phenomena adequately, their causes might remain a mystery. One could hypothesize or speculate as to those causes, but certitude would be impossible, leading Robert Boyle to claim that men might “fancy themselves Eagles,” but were really nothing more than “grovelling Moles incessantly labouring for Light.”9
In formulating their probabilistic natural philosophy, the English virtuosi in particular frequently opposed its central tenets to the Aristotelianism still taught in the universities, using the latter philosophy as a convenient straw man against which to articulate their own arguments.10 At the same time, however, numerous proponents of Aristotle were keenly aware of the potential problems posed by the more extreme forms of skepticism, which led them in turn to examine and embrace forms of probabilism as well. The Jesuits, for example, adapted the curriculum of their many colleges to accommodate a form of probabilism in the seventeenth century, embracing what might be seen as the lesser of two evils. Committed as they were to at least a nominal Aristotelianism, Jesuit educators perceived a greater threat in the rise of extreme forms of skepticism than in adopting some elements of probabilism. The latter allowed them to eliminate a reliance on the dogmatic statements of certain knowledge that were the primary target of the skeptics (some of whom displayed an ironically dogmatic insistence that we can never know anything) and instead to couch their ideas in a more flexible language of likelihood. An example of this probabilistic approach was Mersenne himself, who encountered this way of thinking as a student of the Jesuits and whose philosophical orientation remained, in many respects, indelibly marked by his education. Significantly, this movement towards an intellectual probabilism may have permitted Jesuit thinkers to approach different kinds of knowledge, such as mathematics, in new and useful ways, altering the parameters of their shared philosophy in a fashion that I explore throughout this book.11
While adopting probabilism offered one potential solution to the crisis of certainty, the senses, which played a crucial role in probabilistic knowledge-claims, became ever more problematic in this period. For centuries, philosophers adopting the Aristotelian model of vision had assumed that our senses provided us with accurate representations of the world, and while some, like Aquinas, conceded that our senses were limited, they remained confident that our eyes revealed things as they truly were. In the early modern period, however, a wide range of thinkers and artists began to understand that the act of seeing was far more complicated and unreliable than had been previously believed. The invention of the telescope and, later, the microscope revealed how little of the universe naturalists actually perceived, while the increasingly skeptical tone of early modern philosophy forced a radical re-evaluation of both the value of empiricism and the senses that supported it.
Thus, in numerous aspects of early modern life ranging from demonology and theatre to painting and philosophy, the pleasures and assumptions that had always accompanied the act of seeing became distinctly more problematic.12 As confidence in their senses decreased, natural philosophers had little choice but to turn to language and practices that permitted them to make probable statements about natural phenomena based solely on whatever their senses could perceive and whatever they could infer from appearances. Ultimately, when combined with the increasing prominence of skeptical inquiry, early modern philosophers came to agree that the conclusions drawn from visual experience should be presented only as likely or probable, intended to appeal to subjective sensibilities rather than to any objective or dogmatic truth.13
At the same time, a slow but significant change took place in contemporary ideas about the imagination. Increasing numbers of early modern thinkers looked to the imagination as a way of maneuvering around the problems associated with sense-perception; its ability to act on the rational mind even in the absence of sense-impressions implied that, as part of the act of cognition, one could divorce the imagination to a degree from the skeptical debates concerning the senses that occupied much of early modern philosophy. Prior to this, the utility of the imagination had been discussed frequently in Aristotelian psychology, where it was understood to mediate between the senses and the rational mind but, also, to function primarily in the absence of sense-impressions. Sometimes this meant that the imagination supplied to the mind impressions of objects that had since been removed—this was the faculty that allowed one to recall, for example, the image of a painting that one had seen—but the imagination was also capable of acting in the absence of any object whatsoever, as witnessed in daydreams and fantasies. It was potentially a powerful component of knowing, and while the senses could only relay information about objects, the imagination was free to embellish, manipulate, and construct impressions. This is not to suggest that early modern people saw the imagination as an uncomplicated answer to various epistemological problems. There was in fact a long history of mistrust associated with the imagination, going back to antiquity; Aristotle himself stated at one point that “imaginations are for the most part false.”14
As the prominence and power of the imagination increased, so too did concerns about its ability to provide the mind with false impressions, to open the intellect to demonically inspired phantasia, or even to inflict the individual with melancholia. Nonetheless, the imagination assumed a new and crucial prominence in the sixteenth and seventeenth centuries as thinkers from a range of camps and persuasions struggled to codify a new way of knowing. That the imagination was able to assume this new role had much to do with the changes taking place in early modern theoretical psychology, changes centered around an increasing awareness of the fallibility of both eyes and mind. Thus, the crisis that altered how early modern people understood their own limitations presented opportunities for novel ways of knowing and thinking. Certain elite thinkers among the Jesuits, as we shall see, were well positioned not only to take advantage of these opportunities, but also to display their intellectual versatility by turning their attention to the most difficult of natural philosophical problems: the study of the unseen.
The crisis of certainty acted as a backdrop for a new and, in many cases, critical reassessment of the category of the preternatural, which for centuries had acted as the repository of the secret and unexplained works of nature.15 Meaning literally “beyond nature,” the preternatural was situated, in the standard ontological hierarchy, between the realms of the natural and the supernatural. The supernatural encompassed God and examples of divine works that transcended natural laws; the realm of the natural, by contrast, was the tangible expression of those laws, containing objects and phenomena that demonstrated how nature normally and consistently worked. While the boundaries that defined these two categories were generally unvarying for most thinkers—at least, there was little disagreement about where those boundaries should be—the boundaries of the preternatural were in a constant state of flux, expanding and contracting over the course of centuries. It became a repository for phenomena that did not transgress the basic laws of nature but, rather, that embodied distortions and perturbations of those laws. It was the ontological home of the rare, the hidden, the mysterious, and the monstrous, a catch-all for those things that did not fit easily or comfortably into the placid and well-studied routines of the natural world, and it was its inherent flexibility that made it, for a time, so powerful.
Because the preternatural embodied not the rational and comprehensible laws of nature but, instead, instances when those laws appeared to break down, wrestling with so amorphous and troublesome a category became less and less appealing to early modern intellectuals already grappling with a host of epistemological and philosophical problems. Thus, it is unsurprising that the sixteenth and seventeenth centuries witnessed an increasing desire on the part of naturalists, theologians, and jurists to define more sharply and clearly the ontological borders between things.16 The flexibility of the preternatural, once seen as an asset, eventually became a problem: it was too likely to obscure the boundaries between the miraculous and the mundane. In the wake of the religious and political turmoil that swept across Europe in the sixteenth and seventeenth centuries, any confusion about what was supernatural and what was not—what was a miracle and what was merely imaginative fancy or demonic imposture—became intolerable. The blurring of lines between categories could and did lead to accusations of heresy, and thence to censure, condemnation, and even death.17
The preternatural, then, quickly became problematic for early modern thinkers. It was a negative category, defined not by what it was but by what it was not—that is to say, it embodied neither the regularity of the natural nor the transcendent character of the supernatural. Moreover, as Lorraine Daston and Katharine Park have argued, it was a category “whose limits were defined in practical terms by a pair of unstable criteria both of which depended on the experience and knowledge of the viewer: that which was infrequently experienced or that at which the ignorant wondered.”18 For some early modern philosophers, the preternatural was fundamentally unintelligible; divorced from the usual and intelligible operations of nature, the causes of preternatural phenomena were usually occult or hidden and thus inexplicable.
The inherent subjectivity of personal experience (or ignorance) and the potential for outright unintelligibility, applied over centuries to an ever-changing roster of phenomena, meant that by the seventeenth century the preternatural had become an awkward collection of disparate phenomena, held together by some vague ontological identity but lacking any kind of meaningful coherence as a category.19 The boundaries that provided some vague form to the preternatural were also inherently unstable: on the one side lay miracles and other instances of divine intervention, which were the subject of intense theological debate in this period; on the other lay the ordinary workings of nature, which were themselves the subject of intense debate among natural philosophers.20 As these debates continued, they could not help but distort the boundaries that defined the preternatural, and the resulting ontological instability reverberated throughout early modern intellectual culture and beyond, into a widespread and popular preoccupation with prodigies, wonders, marvels, and other examples of nature’s seemingly infinite capacity to amaze and astound.
The myriad examples of nature’s mysteries defined what we might call the culture of marvels, and its heyday, like that of the preternatural, stretched from the Middle Ages through to the early years of the eighteenth century. Both the preternatural and the culture of marvels were rooted in the understanding that, rather than being bound by strict and immutable laws, nature worked in regular but by no means determinate ways. Exceptions to the ordinary course of nature were, if not common, then at least inevitable, and these exceptions were frequently invested with cultural meaning. Inexplicable phenomena such as comets and monstrous births were often interpreted as prodigies, messages or warnings freighted with supernatural meaning, while princes, cardinals, and the upwardly mobile middle classes all constructed variations on the Kunstkammern, cabinets of curiosities that became tangible expressions of wealth and erudition as well as of nature’s propensity for producing marvels.21
Early modern wonders preoccupied a broad swathe of the European population; until roughly the middle of the seventeenth century the preternatural received enormous amounts of attention from philosophers, theologians, physicians, and ordinary people alike.22 Some thinkers resisted this attention paid to the preternatural; many Aristotelians, for example, deliberately excluded wonders and marvels from natural philosophy in the sixteenth and seventeenth centuries. They found this practice increasingly challenged by a new breed of intellectual, however: the “preternatural philosophers,” who not only focused their attention on natural marvels but also sought to rescue these phenomena from the fringes of respectable intellectual discourse and place them instead squarely at the core of the study of nature.23 Despite the shortcomings of the preternatural, there were important reasons why these philosophers might have found its study useful. By embodying perturbations from the norm, it highlighted what that norm was and how it (usually) operated.
However useful some naturalists found the study of the preternatural, this attention did not last. Its disappearance from most philosophical discourse by the early decades of the eighteenth century might be linked to what historians have called the “disenchantment of nature,” whereby Europeans in the late seventeenth century supposedly rejected magical thinking and superstition and turned instead to orthodox religion or rational science.24 Though it fits comfortably into progressive narratives of the rise of modernity, however, this notion of “disenchantment” hardly squares with how people lived, wrote, and thought in the seventeenth century. The many marvels of nature continued to fascinate even the supposedly rigorous experimentalists of Europe’s scientific societies well into the eighteenth century, and while many rejected claims that such marvels were divine prodigies or diabolical machinations, these exemplars of nature’s secrets nonetheless remained subject to intense scrutiny by naturalists throughout this period.25
For all of its associated problems, the preternatural was important because any study of nature’s secrets, of its hidden properties and forces, inevitably overlapped with the ontological home of such phenomena, and it was precisely these phenomena that became a focus for natural philosophical inquiry in the sixteenth and seventeenth centuries. At the same time, however, early modern philosophers came to see some value in marginalizing and diminishing the preternatural; its inherent and growing instability threatened the entire ontological order of things. They could not afford to embrace a boundary between nature and the divine that was so unstable, and increasingly they sought to establish firm distinctions between these two realms even as they rejected claims and ideas that threatened to blur ontological lines.
Given that the stakes were both theological and philosophical, it is likely that the Jesuits would have been attuned to the problems posed by the preternatural. Indeed, the Catholic Church had long worked to diminish this category as part of its efforts to construct a simplified ontology that reinforced the distance between the miraculous works of God and the mundane workings of nature. Following the Council of Trent around the middle of the sixteenth century, the Church emphasized the importance of miracles, seeing them as a means of legitimizing the Catholic faith. This meant, however, that miracles had to be vetted with extraordinary care, to be certain that each was, in fact, an authentic example of divine activity. This increased vigilance on the part of Church authorities called for firm and irreproachable distinctions between what was properly supernatural and what was not. Thus, when members of the Spanish Inquisition confronted religious enthusiasts and other supposed pretenders to supernatural revelation, they tended both to fortify existing definitions of the supernatural and to naturalize “borderline” phenomena, those that belonged traditionally to the preternatural but that might blur the ontological boundaries that the Inquisition was so desperate to reinforce. Such phenomena were subjected to the rigors of natural philosophical inquiry and deemed either “properly” natural or fraudulent.26
As the supernatural was fortified and the natural expanded, what lay between them—the preternatural—was slowly squeezed towards irrelevance. Well beyond the activities of the Spanish Inquisition, the expansion of “the natural” in European philosophy involved the steady naturalization of the preternatural, in which particular phenomena were singled out and shown to be neither mysterious nor strange. As the rest of this book will demonstrate, an interconnected group of prominent Jesuits engaged enthusiastically in precisely this sort of boundary-work, transforming the wonders of nature into natural and explicable oddities. The result was a diminishment of the preternatural and an end to nature’s secrets, in service to greater ontological clarity.
1 Richard H. Popkin, The History of Scepticism from Erasmus to Descartes (Assen: Van Gorcum, 1964), p. ix.
2 Popkin, pp. ix–x.
3 Francis Bacon, The Works of Francis Bacon, ed. James Spedding, Robert Leslie Ellis, and Douglas Denon Heath (London: Houghton Mifflin, 1857), vol. VII, p. 88: “Hinc schola Academica, quae Acatalepsiara ex professo tenuit, et homines ad sempiternas tenebras damnavit.”
4 Ephraim Chambers, Cyclopædia, or, An universal dictionary of arts and sciences (London, 1728), p. 14.
5 Popkin, p. xi.
6 Popkin, p. 132.
7 Barbara J. Shapiro, Probability and Certainty in Seventeenth-Century England: A Study of the Relationships Between Natural Science, Religion, History, Law, and Literature (Princeton, NJ: Princeton University Press, 1983).
8 Steven Shapin, A Social History of Truth: Science and Civility in Seventeenth-Century England (Chicago: University of Chicago Press, 1994).
9 Shapiro, pp. 62, 22.
10 For a clear understanding of attitudes towards Aristotle in the Royal Society, see Thomas Sprat’s The history of the Royal-Society of London for the improving of natural knowledge (London, 1667), particularly his discussion of “the Philosophy of the Schole-men” on pp. 15–22.
11 Peter Dear, Mersenne and the Learning of the Schools (Ithaca, NY: Cornell University Press, 1988); see also his Discipline and Experience: The Mathematical Way in the Scientific Revolution (Chicago: University of Chicago Press, 1995); Robert A. Maryks, Saint Cicero and the Jesuits: The Influence of the Liberal Arts on the Adoption of Moral Probabilism (Aldershot: Ashgate, 2008).
12 For a comprehensive study of these changing attitudes towards vision, see Stuart Clark, Vanities of the Eye: Vision in Early Modern European Culture (Oxford: Oxford University Press, 2007), and also Walter S. Melion and Lee Palmer Wandel, Early Modern Eyes (Leiden: Brill, 2010); on the problems raised by the introduction of instruments, see Ofer Gal and Raz Chen-Morris, “Empiricism Without the Senses: How the Instrument Replaced the Eye,” in Charles T. Wolfe and Ofer Gal, The Body as Object and Instrument of Knowledge: Embodied Empiricism in Early Modern Science (London: Springer, 2010), pp. 121–48; Gyorgy E. Szonyi, “Perception, Vision, Phantasmagoria: Ways of Seeing in the Early Modern Period and Since,” Aries, vol. 11, no. 1 (2011), pp. 53–75.
13 Clark, Vanities of the Eye, p. 270.
14 Clark, pp. 44–5. For more on the imagination and its connections with early modern science, see Guy Claessens, “Imagination as Self-Knowledge: Kepler on Proclus’ Commentary on the First Book of Euclid’s Elements,” Early Science and Medicine, vol. 16, no. 3 (2011), pp. 179–99; Thomas L. Hankins and Robert J. Silverman, Instruments and the Imagination (Princeton, NJ: Princeton University Press, 1995).
15 Changing understandings of the preternatural lie at the heart of Lorraine Daston and Katharine Park’s Wonders and the Order of Nature, 1150–1750 (New York: Zone Books, 1998). Similarly, Stuart Clark discusses the preternatural in the context of early modern demonology; see his Thinking with Demons: The Idea of Witchcraft in Early Modern Europe (Oxford: Oxford University Press, 1997), in particular the chapters that make up the section on “Science.”
16 Lorraine Daston, “The Nature of Nature in Early Modern Europe,” Configurations, vol. 6 (1998), pp. 149–72.
17 While an enormous subject in itself, the history of European heresy is revealing of how this blurring of boundaries was often tied up with accusations of heretical activity; for examples, see Gary K. Waite, Heresy, Magic, and Witchcraft in Early Modern Europe (New York: Palgrave Macmillan, 2003); Carlo Ginzburg, The Cheese and the Worms: The Cosmos of a Sixteenth-Century Miller, trans. John and Anne Tedeschi (New York: Penguin, 1982); John Tedeschi, The Prosecution of Heresy: Collected Studies on the Inquisition in Early Modern Italy (Binghamton, NY: Medieval & Renaissance Texts & Studies, 1991).
18 Daston and Park, p. 126.
19 Clark, Thinking with Demons, p. 262.
20 Clark, Thinking with Demons, p. 177. On the utility of the preternatural, see also Des Chene’s Physiologia: Natural Philosophy in Late Aristotelian and Cartesian Thought (Ithaca, NY: Cornell University Press, 2000), p. 218.
21 The most comprehensive survey of the culture of marvels remains Daston and Park’s Wonders and the Order of Nature, but see also Pamela H. Smith and Paula Findlen, Merchants and Marvels: Commerce, Science, and Art in Early Modern Europe (New York: Routledge, 2002); on Kunstkammern and the culture of collecting, see Paula Findlen, Possessing Nature: Museums, Collecting, and Scientific Culture in Early Modern Italy (Berkeley: University of California Press, 1994); Pamela H. Smith, The Body of the Artisan: Art and Experience in the Scientific Revolution (Chicago: University of Chicago Press, 2004).
22 Daston, “The Nature of Nature in Early Modern Europe,” p. 162.
23 Daston and Park, p. 160.
24 On the idea of “disenchantment,” see Keith Thomas, Religion and the Decline of Magic (New York: Scribner, 1971); Robert W. Scribner, “The Reformation, Popular Magic, and the ‘Disenchantment of the World,’” Journal of Interdisciplinary History, vol. 23 (1993), pp. 475–94; Charles Webster, “Paracelsus, Paracelsianism, and the Secularization of the Worldview,” Science in Context, vol. 15 (2002), pp. 9–27.
25 Daston makes this case eloquently in her “The Nature of Nature in Early Modern Europe.”
26 Andrew Keitt, “Religious Enthusiasm, the Spanish Inquisition, and the Disenchantment of the World,” Journal of the History of Ideas, vol. 65, no. 2 (April 2004), pp. 236–7.