Newton and the Origin of Civilization

By Jed Z. Buchwald and Mordechai Feingold

Isaac Newton's Chronology of Ancient Kingdoms Amended, published in 1728, one year after the great man's death, unleashed a storm of controversy. And for good reason. The book presents a drastically revised timeline for ancient civilizations, contracting Greek history by five hundred years and Egypt's by a millennium. Newton and the Origin of Civilization tells the story of how one of the most celebrated figures in the history of mathematics, optics, and mechanics came to apply his unique ways of thinking to problems of history, theology, and mythology, and of how his radical ideas produced an uproar that reverberated in Europe's learned circles throughout the eighteenth century and beyond.


Jed Buchwald and Mordechai Feingold reveal the manner in which Newton strove for nearly half a century to rectify universal history by reading ancient texts through the lens of astronomy, and to create a tight theoretical system for interpreting the evolution of civilization on the basis of population dynamics. It was during Newton's earliest years at Cambridge that he developed the core of his singular method for generating and working with trustworthy knowledge, which he applied to his study of the past with the same rigor he brought to his work in physics and mathematics. Drawing extensively on Newton's unpublished papers and a host of other primary sources, Buchwald and Feingold reconcile Isaac Newton the rational scientist with Newton the natural philosopher, alchemist, theologian, and chronologist of ancient history.

• Language: English
• Publisher: Princeton University Press
• Release date: Nov 11, 2012
• ISBN: 9781400845187

Book preview

Civilization

Introduction

Newton’s writings on biblical subjects seem to me especially interesting because they provide deep insight into the characteristic intellectual features and working methods of this important man. The divine origin of the Bible is for Newton absolutely certain, a conviction that stands in curious contrast to the critical skepticism that characterizes his attitude toward the churches. From this confidence stems the firm conviction that the seemingly obscure parts of the Bible must contain important revelations, to illuminate which one need only decipher its symbolic language. Newton seeks this decipherment, or interpretation, by means of his sharp systematic thinking grounded on the careful use of all the sources at his disposal.

—Draft of a letter from Albert Einstein to Abraham Yahuda.

September 1940¹

In 2006, archaeologists announced that the ancient Minoan kingdom on the island of Crete was a century older than had been thought. Radiocarbon dating of tree rings and seeds, coupled to statistics, placed the volcanic explosion of Thera, which likely ended the Minoan period, to between 1660 and 1613 BCE. This had disturbing consequences. It had been long held that the Minoan period overlapped the New Kingdom in Egypt, which began about 1550 BCE, and that contacts existed between the two civilizations. The revised dating made this impossible, since at the earlier time the Egyptians were ruled by Canaanite foreigners, the Hyksos. Nevertheless, the New York Times reported, early indications suggest that proponents of the later chronology are not backing down. Their main line of defense is the Egyptian historical chronology, derived from its written records as well as pottery and iconography. They insist that a chronology tied to the Egyptian record could not be off by as much as 100 years. Evidence drawn from a source that knows neither culture nor history—the traces of radiocarbon—suddenly battled in 2006 with the remnant words and art of antiquity. Still, the proponents of text and relic held their ground, while an archaeologist argued that the dates offered in the textbooks for these periods have always been interpretations and estimates with little evidence. The proper solution requires realigning the Aegean and Egyptian chronologies for the period 1700–1400. Equipped with statistical methods, scientific archaeology makes chronological claims with which ancient words and arts must contend.²

Disputes over chronology with overtones of a divide between the text and the laboratory or field, between the humanist and the scientist, have been raging since the sixteenth century. Though even in antiquity bits of astronomy had intrigued those interested in chronology, only after the Reformation did calculation begin to intersect fruitfully with philology. Anthony Grafton notes that in Rudolphine Prague, where Johannes Kepler lived and worked for a time, astronomy and chronology were fused into a single pursuit not identifiable with any modern discipline. The barriers between humanistic scholarship and computational science had not then been fully erected, and considerable interaction took place between philology and astronomy. Nevertheless, signs of discord were already visible. The great humanistic scholar Joseph Scaliger, though not by any means the first to make use of astronomical tidbits to reset chronology’s clock, corresponded with both Kepler and Tycho Brahe in his attempt to elicit satisfying results by means of an astronomical armamentarium. A century later, the relationship between the two disciplines turned decidedly frosty when Isaac Newton intruded calculations into the precincts of history and philology by virtually turning certain texts into numbers and tampering with others to fit his reckonings.³

Around 1700 (and concertedly so by 1704), the fifty-eight-year-old Newton—then Master of the Mint—began applying himself seriously to technical chronology, supplementing the historical studies he had been working on for the past decade and a half. The extensive notes he took ranged from excerpts of, and commentaries on, such classical sources as Herodotus, Clement of Alexandria, Diodorus Siculus, and Eusebius, to material extracted from Scripture, and elaborate astronomical and genealogical computations. The astronomical material was drawn for the most part from Denis Petau’s Uranologion, which included a Latin translation of Hipparchus’ critical Commentary on Aratus’ third century BCE poem on the heavens. The Commentary provided Newton with a spectrum of remarks, many of which could, he thought, be transformed into numbers. The motivation for doing so derived from his concern with issues in antiquity that bore on the origin of civilization. Having first followed common tradition, in fixing the origin of kingdoms shortly after the Deluge, he became convinced that elaborate kingdoms and city life emerged only toward the beginning of the first millennium BCE. Gripped to a greater extent than his contemporaries by questions relating to the amount of time needed for the earth’s population to recover from the devastation of the Flood, Newton convinced himself that neither Egyptian nor, certainly, Greek civilization could have existed much before the time of Solomon’s reign.

As a historical chronologer, Newton seems hardly the person whose name would become an eponym for natural philosophy during the Enlightenment. Odd though it may seem for the modern observer, his pursuit of chronology is not the only seeming idiosyncrasy. As recent scholarship has demonstrated, Newton was thoroughly immersed in ancient prophecies, Church history, and alchemy. These investigations raise several questions: what links his interest in such matters to his investigations in optics, mechanics, and mathematics? Was Newton in his alchemical laboratory the same Newton who analyzed the passage of light through a prism and who measured the behavior of bodies falling through fluid media? What did the Newton who interpreted the Book of Revelation have to do with the man who wrote the Principia Mathematica? And how does the Newton who pored over ancient texts square with the author of the Opticks?

In several respects, Newton as natural philosopher differed little from numerous other early-modern observers, experimenters, and calculators who toiled incessantly in their workrooms and at their desks. Surviving manuscripts attest to the passion that drove them to formulate and to solve problems of nature and of mathematics. Galileo tangled intensely, and repeatedly, with questions of motion; the young Newton computed logarithms to dozens of places with evident joy; Boyle avidly probed the workings of air pumps, the combinations of chymistry, and the complexities of colors. The sheer power of an irresistible need to observe, to experiment, to formulate, to grapple with a problem and crack it shines through their labors. And yet, whoever spends enough time with Isaac Newton realizes not only the pleasure he took in calculating and in experimenting (and in little else besides), but his conviction that the cosmos reveals the presence of an active deity. What unites the Newton who probed nature’s secrets and delighted in the intricacy of computation with the Newton who hunted the secrets of prophecy and of divinely guided human destiny? Are these two different mind-sets in a single body? Is the Newton who pondered divine activity the real Newton, whose theological convictions informed the calculator and experimenter? Or is there another possibility? To us, this late seventeenth-century genius was not simply driven by this to do that; rather, his way of working reveals a mode of thought and practice which underpins both his efforts to unravel the workings of a deity in history and to grasp the innermost mysteries of mechanical nature.

Frank Manuel is the only one to date to have engaged seriously with Newton the chronologer, seeking always to forge a unity out of his apparently disparate life’s work. Subsequent scholars have built on and extended Manuel’s insights regarding the coherence of Newton’s work and persona. Since the 1970s, several have placed particular emphasis on the character of Newton’s theology and on his investigations into the Apocalypse.⁴ Others have opened the way to serious consideration of his alchemical investigations.⁵ In this context, Newton’s procedures in the alchemical laboratory have been replicated in recent years, together with analyses that demonstrate how thoroughly his work there was grounded in a vision of matter composed of corpuscles, an understanding that has a long history among alchemists.⁶

Still, the nature of the connections between Newton the mathematician, the experimental philosopher, the corpuscular alchemist, the expositor of the Apocalypse, and the originator of a new system of chronology remains obscure. Manuel wondered what effect Newton’s scientific method had on such matters, but at the time, the precise meaning of that method—if it ever existed—remained unclear. Since then, scholars have discovered that the Newton of the Principia did exploit a particular manner of thinking about and investigating nature, which has been termed the Newtonian style. Analysis of that style has shown that Newton had a most specific way with data and conjecture.⁷

It was during Newton’s earliest years at Cambridge that he developed the core of his method for generating and working with trustworthy knowledge—a core that carried forward directly into his chronology and indeed into his writings on the Apocalypse and the origins of civilization. We will not be asserting that a single, unchanging Newton can be followed through the nearly nine decades of his life. How could that even be? How could a man in his seventies and eighties be the same person in all respects as the youth who arrived at Cambridge in 1661? Changes certainly occurred over the years, as the introverted young man grew into the socially adept and ever-vigilant president of the Royal Society. Nevertheless, Newton’s mature approaches to nature, history, and theology are rooted deep in his undergraduate career. Attitudes forged in those years evolved a way of trusting—and distrusting—evidence that produced a singular commonality among these apparently disparate realms. Critics of his chronology sensed this presence: hints of something inimical to, perhaps even dismissive of, the kinds of reasoning that philologists and theologians steeped in texts had long deployed. They were right to sense danger. Newton’s ways with the past implicitly posed the questions: who has the right to command history? What sorts of evidence and reasoning should govern historical and theological understanding?

The old chronologer and the young natural philosopher deployed a complex conception of what is knowable, a conception that diverged radically from contemporary expectations of the knowledge that can be harvested from experiments—or from texts. We will see how Newton’s scheme for human history is shot through and through with this structure, while his commitment to divine action in both nature and history cannot be separated from his understanding of how reliable knowledge in both domains can be gleaned or generated. Newton, we will argue, was not motivated by a conception of divine action to query nature; rather, a single conception of the probing character of human knowledge bound together a Newtonian triad of history, theology, and science.

In turning to chronology, Newton relied in the first instance on contemporary English work. Though the subject of technical chronology had not been extensively pursued in England during the seventeenth century, there was a rich native tradition in higher criticism, and a spectrum of ongoing controversies about the origins of language and of civilized life. These concerns had been greatly furthered by new reports of Chinese civilization, as well as by experiences of native cultures in the New World. Newton was certainly aware of such developments, but there is little evidence that he devoted much attention to them (except, in the case of China, when he briefly attempted to dismiss seeming countervailing evidence to his several claims). He remained principally concerned with the chronologies of Egypt, Greece, and Mesopotamian empires. By the time Newton undertook extensive studies in the area, or in matters theological that were bound to ancient evidence, he had already developed his novel approach to what can be known through nature or through text.

We begin with the young Newton at Cambridge, where he grappled with new scientific ideas, subtly but distinctively transforming them. It was then that he developed a specific kind of skepticism concerning the reliability of the senses, one that powerfully governed his ways in the laboratory and in calculation. Convinced that the senses could not be relied upon to generate reliable knowledge, Newton developed a way to overcome this limitation by taking the extraordinary tack of increasing the number of measurements without discarding any. He alone forged a trustworthy resultant out of a discrepant set of numbers, each of which was inherently unreliable, by taking an average among them. Instead of discarding every measurement other than the one thought to be the very best, as his contemporaries usually did, Newton kept them all, thinking that a good number could be produced by combining a multitude of bad ones.

Newton’s way to eradicate error passed strikingly, and seamlessly, into his theological and chronological works, shaping the particular forms of his reasoning. In his writings on the Apocalypse, Newton required multiple sources—each subject to various degrees of doubt—to be balanced against one another. Although that in itself was hardly a new procedure, Newton’s skeptical attitude toward singular pieces of evidence resulted in a novel understanding of the significance of the remarks in the books of Daniel and Revelation. That understanding was directly connected to his conviction that the deity’s activity followed an essentially law-like structure even in matters that engaged human affairs.

Newton’s turn to chronology was stimulated in major ways by a concern that he shared with few contemporaries: namely the amount of time required to repopulate the earth after the Noachian Deluge. Difficult issues plagued discussions of these matters, and Newton grappled with them all. Increasingly convinced that regularities observable at his time must have prevailed among the survivors of the Deluge as well, Newton eventually developed a novel theory of the evolution of civilization, one that required chronology’s clock to be radically reset. Human populations, he decided, expand according to certain rules that implicate specific stages in the development of civilization. Although ancient texts suggested to most interpreters a very different sequence and timing of developments, by the late 1690s, Newton had also decided that these sources could not be relied upon unless they had a particular pedigree—namely, unless they had come down through a trustworthy chain of transmission. The prime example of such a proper transmission for Newton was the Masoretic version of Scripture. Otherwise, he thought, texts—especially texts written in the form of poetry rather than prose—had to be treated with a great deal of skepticism, which licensed Newton’s frequent, radical reinterpretations.

Newton’s especial vehemence in this regard was likely furthered by his work in the London Mint, where he had for some time been in charge of prosecuting coin clippers and counterfeiters. His experience in taking testimony exacerbated his skepticism concerning the reliability of words, especially words that could not be turned into numbers or balanced against corroborating testimony. As he saw it, words from the past resembled the sorts of stories that he had heard from clippers and counterfeiters who could not be trusted. In tackling chronology, Newton accordingly rejected ancient remarks that struck him as poetical fancies, thinking poetry to be, sui generis, a form of fictive storytelling. Nor could singular remarks even in prose be relied upon—unless they could be transmuted into numbers. That could be done by creatively manipulating Hipparchus’ Commentary. From it Newton extracted statements concerning the parts of constellations passed through by the colures, the great circles that pass through the poles and, respectively, the equinoxes and solstices. After considerable effort turning text into numbers—work that required him to engage creatively (and, his critics claimed, arguably) with images of the constellations—Newton produced a set of discrepant numbers out of which error was drained by means of the average. Although he eliminated the computations from his published Chronology, Newton’s extensive manuscripts, which were written and rewritten over more than two decades, have enabled us to reconstruct his reasoning.

The astronomical remarks that Newton used pertained, he believed, to the very first stellar sphere, which had been passed down to Eudoxus through the centuries. The result of his calculations gave him precisely what he sought: traditional chronology was too long by five centuries. In particular, the expedition of the Argonauts must have occurred ca. 939 BCE, and not in 1467, as one of his French critics maintained. Egypt fared similarly in Newton’s hands. Here his argument relied principally on identifying the Egyptian pharaoh Sesostris with the Biblical Sesac—an identification that he found in the work of John Marsham—which enabled him to contract Egyptian history by six hundred years.

Newton’s iconoclastic chronology generated antagonistic reactions in both England and France, several years prior to its posthumous publication in 1728. In France, a storm of controversy greeted his claims and methods, as they made their way there through various intricate paths that Newton himself may have had a hand in clearing. French reactions were especially pointed as the erudite members of the Académie des Inscriptions et Belles Lettres, who fought enough among themselves, perceived that Newton’s Chronology attacked more than their elaborately constructed dating systems: it undermined the very foundations of their methods grounded for the most part in texts. During the seventeenth- and early eighteenth centuries, skepticism concerning the reliability of texts, and historical Pyrrhonism, had become rampant, and attempts were made to establish criteria for judging the reliability of evidence from the past.⁸ Material relics were used increasingly to challenge or to buttress ancient texts. However, since Newton scarcely relied on inscriptions, medallions, or coins—his main periods of interest predated these forms of evidence—even those Academicians who had turned to these relics from the past to grant a competitive philosophical luster to their work felt threatened. In England, Newton’s scheme for ancient history elicited powerful critiques, not least from the verbose but accomplished William Whiston, furious that Newton had not publicly avowed the Arianism that Whiston so vehemently preached. For almost a century, the immense reputation of the great Newton forced historians, chronologers, and theologians to come to grips with the challenges that his Chronology of Ancient Kingdoms Amended posed. In the process, new foundations for the study of ancient history, archaeology, and Biblical exegesis were laid, rapidly eclipsing the venerable domain of chronology, which increasingly remained the preserve of orthodox theologians.

The Newton that is the subject of this book differs in striking ways from any scientist of the twenty-first century. But he differed as well from his contemporary natural philosophers, theologians, and chronologers. That difference is both our subject and our method, as we investigate its origin and then use it to produce a new understanding of Newton’s worldview and its historical context.

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¹ ALS, 1p. [AEA 39-602], Albert Einstein Archives, by permission of the Hebrew University and Princeton University Press.

² Kwan, 2006; Wilford, 2006. Archaeologist Sturt Manning of Cornell University.

³ Grafton, 1991b, p. 186. See Grafton, 1993, esp. 3.4.

⁴ See, e.g., Iliffe, 1994, 1995; Snobelen, 1999, 2003a, 2003b, 2004; Mandelbrote, 2002; Delgado-Moreira, 2006b, 2006a.

⁵ Dobbs, 2002; Figala, 2002a.

⁶ Newman, 1998; Newman and Principe, 2001, 2002, 2003; Newman, 2006.

⁷ Cohen, 1980; Smith, 2000a, 2002.

⁸ Though published more than six decades ago, Momigliano, 1950 remains a formidably readable and informative account of these developments, about which a great deal has since been written. See especially the several essays in Grafton, 1991a, 2001b.

1

Troubled Senses

In 1583, the Huguenot scholar Joseph Scaliger published his De Emendatione Temporum. There he examined the chronologies of Babylon, Egypt, and Persia, as well as those of Greece and Rome, arguing for an amended structure based in substantial part on antique reports that could be given astronomical significance, in particular eclipses, as well as on ancient calendars. Scaliger was hardly the only one to use astronomical evidence to date the past. Another Protestant, the theologian Heinrich Bünting, had employed eclipse reports with great technical proficiency in his Chronologia (1590).¹ Scaliger and Bünting were followed by others in the seventeenth century who also relied on eclipses to date the past, including the Protestant Sethus Calvisius and the Jesuit Denis Petau (Petavius). Grafton calls such men systematic chronologers—their technical expertise plied to produce treatises on ancient and modern calendars and epochs, and so markedly different from humanistic chronologers, editors of ancient texts, and antiquarians.² Calvisius, for example, remarked in 1605 that historians frequently record eclipses, and they are often inserted into accounts of the deeds of kings and emperors, in such a way that they usually provide the most certain testimony both about the length of any given king’s reign and the true course of events. Eclipses are of infallible certainty, and they can be dated and demonstrated by astronomical computation for any period.³

Eclipse reports from antiquity certainly raised issues of accurate reportage and textual corruption, but they seemed not to require an interpretative framework. Eclipses are after all singular events that, it seemed, could be connected to chronology by means of the technical tools of astronomy that had become available with the publication of Erasmus Rheinhold’s Prutenic Tables in 1551, which made use of the basic numerical parameters that Nicholas Copernicus had deployed in his 1543 De Revolutionibus Orbium Coelestium.⁴ The use of astronomy in matters chronological produced occasional antagonism, but the assimilation of singular human to singular celestial event apparently did not raise philosophical problems, at least among the technical chronologers. Even when a celestial event was granted portentous significance, its astrological meaning derived from its place in an established system of knowledge and not from its signaling a natural novelty. This raises the question of the relationship between natural and historical knowledge in the late sixteenth- and seventeenth centuries, which, in turn, brings us to consider changes in the character of natural knowledge proper during this period—an extraordinarily large and complicated issue that has garnered considerable attention.

A great deal of historical work concerns the sense in which a specifically experimental form of knowledge emerged during the seventeenth century. It has been argued that until the last half of the century, experiment-based knowledge remained suspect. When it became respectable to glean information about nature from experiment, the argument continues, specific techniques had to be invented to make the process socially and (ipso facto) intellectually acceptable.⁵ Three distinct but related strands wind through this argument. First and foremost, how could artificially produced experiences become accepted as foundational for proper knowledge when traditional scholastic categories sharply distinguished between the natural and the artefactual? Second, artefactual knowledge is not merely non-natural (in the sense of not being produced by unaided nature); it is also singular and specific, referring to the results of particular interventions. That too is thought to conflict with scholastic tradition, according to which proper knowledge of nature must be founded on experiences that are universal and common. Finally, how did experimentally derived knowledge, grounded in particulars, become conjoined with mathematical demonstration when the scholastics had long considered that mathematics applied only to those sciences whose objects partook in their essence of geometric qualities?

There have been various answers to these questions, but in respect to the first two, all presume that there was in fact a broadly enforced barrier between the experiment and proper knowledge. Yet even if such a division existed among some scholastics—and the claim remains controversial—it hardly follows that the boundary was effectively policed everywhere before the mid-seventeenth century; it certainly was not. Historians of alchemy have for example demonstrated that practitioners regularly and unproblematically produced and worked with laboratory-generated knowledge, and that one of the prime examples used to illustrate the novelty of the matter-of-fact as a privileged item, namely Robert Boyle, derived a good deal of his approach from the alchemist George Starkey.⁶ Much of the difficulty in developing a full understanding of the emergence of widely pursued laboratory science may derive from concentrating on methodological prescriptions rather than on actual practice, which alone reveals what was being done; prescriptive pronouncements in contrast mostly uncover reactions to activity and not its generative sources.

Though experiment-based facts were not uncommon by the sixteenth century, and probably long before that, the question of how locally produced results could be incorporated into the foundations of knowledge systems inevitably arose—as they do to this day. Novelties always generate questions when they come into contact with an existing structure, however loosely built the system may be. An event of nature, whether generated in a laboratory or out of it, certainly occurs in time and place. It is also true that in mid- to late seventeenth-century England, natural histories were produced that recount specific events. However, many of these—such as Boyle’s narratives concerning color of 1664—aimed to establish claims that, though limited in various ways, nevertheless transcended the place and time of their original production.

Consider the following example. At the beginning of the third part of his history of colours, Boyle described an experiment performed on October the 11. About ten in the Morning.⁷ He continued by providing a perfect example of an experiment specified in time, place, and circumstance. But it was done in the service of a claim that holds outside locality; Boyle did it in the first place because that, according to the conjectures I have above propos’d, one of the most general causes of the diversity of colours in opacous bodies, is, that some reflect the light mingl’d with more, others with less of shade … I hold it not unfit to mention in the first place, the experiments that I thought to examine this conjecture.⁸ Specifically local the experiments certainly were, but they were intended to be of a type that could be regenerated elsewhere.

In this respect, a historical event of the sort explored by chronologers is a very different kind of beast from knowledge about nature because it is inherently and inevitably singular: an event of history cannot be reproduced in other places and at other times unless it is taken to be exemplary of a type that transcends the specific event’s locality. Caesar’s crossing of the Rubicon in 49 BCE is unreproducible, but not simply because 49 BCE occurred only once; after all, Boyle’s October 11 experiment also occurred just once. Rather, Caesar’s incursion cannot be reproduced because the people involved and the technological, economic, political, environmental, psychological, and social circumstances irretrievably alter over time, whereas the character of the event is embedded in the complex specificities of its original occurrence. Boyle would in contrast assert that his October 11 experiment could be reproduced everywhere and by anyone—although perhaps with difficulty—precisely because he intended it to provide evidence for a locality-transcending claim. Natural events that occur without human intervention—which are of the sort that, to a pure-bred scholastic, are the only true products of nature—would constitute for Boyle an exception to the rule only in the sense that they might not be reproducible by human agency, though not because human actions might somehow step outside nature’s course. Only divine interventions and spirits (in both of which Boyle firmly believed) could do that.

The differences between historical and natural events have consequences for evaluations of novelty. In Boyle’s world, an experiment designed to substantiate a claim that does not work as expected may provide evidence against the claim and suggest alternatives to it. Laboratory novelties have locally transcendent meaning just because they may, or may not, support claims or suggest new directions. Historical events cannot provide surprises or point out new paths, which is to say that they cannot constitute proper novelties, unless they too are linked into a wider scheme of knowledge that gives them general significance. To return to the river-crossing Caesar, if we knew enough about the circumstances to fit this and subsequent events into a class of military endeavors, then we could say that the event’s significance transcends its locus and time of production—in which case the event would be an exemplar within a broader system of knowledge.

The technical chronologers of the early modern period did not produce knowledge systems in anything like this sense. They developed instead systems of concordances and sequences that located events of human history in time by means of their simultaneous occurrences with particular astronomical events, usually eclipses. Put differently, the likes of Scaliger aimed to use their collections of happenings to establish chronologies and not to uncover or demonstrate general theories about history. Neither Scaliger nor Bünting were embryonic Giambattista Vicos, who did produce just that, odd and fantastic though Vico’s scheme appears to twenty-first-century eyes.⁹

It is precisely here that Isaac Newton, as a chronologer, differed programatically from his predecessors: he sought to use astronomical tools to mold singular events into a system for understanding ancient history, indeed for grasping the entire development of civilization—what’s more, we shall see, a system that shared and exemplified the same evidentiary and argumentative structure deployed in his science. Consequently, Newton faced a new kind of problem—new, that is, in technical chronology. Historical remnants can be known of course only through the transmitted testimony of individuals whom no one living has ever met. Humanists had long developed methods for handling the inevitable results of corruption and fraud over the centuries. In Newton’s chronological world, the chains of transmission ran back to a period before the very existence of written records in Greek, or at least to a period when Greek literacy was in its infancy, whereas the eclipses that the technical chronologers had used all derived from literate eras. More problematic still, the remnant testimonies that reached back to that pre-literate time did not concern precise astronomical events. They described instead characteristic, but comparatively inexact, features of the heavens, and they referred to them in words that required interpretation. For unlike eclipses, which become dates via the mathematics of astronomy, the features at Newton’s disposal could not be easily transmuted into numbers. Most significant of all, even when Newton did effect his transformations, the numbers that emerged did not agree with one another.

Ultimately, Newton would produce from these discrepant numbers a determinate date that, if correct, would fundamentally alter all previous chronologies—and indeed would challenge contemporary understanding of the human past. That date did not emerge from just one among the numbers into which Newton had transformed ancient words, but from all of them together. This manufacture of harmony out of discord was not only new in historical chronology, but unprecedented in natural philosophy before Newton’s own work in optics in the late 1660s and early 1670s. He alone had developed a method that not only permitted, but actually urged, the experimental production and subsequent amalgamation of discordant numbers—a method that directly informed Newton’s historical chronology.

Newton’s career spanned nearly seven decades, a period that witnessed profound changes in the many methods, techniques, conceptions, and practices that together constitute the late period of Early Modern mathematics and natural philosophy. He himself was responsible in several ways for a good number of these changes.¹⁰ So protean a career as Newton’s, which continued to generate new results through the 1690s, can hardly be expected to exhibit a single continuous strand of development. Nevertheless, by the early 1670s the young Newton had developed the contours of method and technique, as well as a number of specific conceptions in optics and mechanics, and (especially) mathematics, that the mature scholar adopted, adapted, reworked, and deployed in subsequent decades.¹¹ These several and disparate explorations were undertaken in the context of mid-seventeenth-century views concerning nature, mind, God, and the links among them. His own understanding of these matters evolved during his early years at Trinity College, Cambridge, which he entered in June 1661 at the age of eighteen and a half. Over the next half decade, the solitary scholar¹² encountered a considerable amount of seventeenth-century learning, and he systematically set down many of his thoughts and textual extracts in a notebook, part of which he titled Questiones quaedam Philosophicae (Certain philosophical questions). Here we find the young Newton first grappling with issues which had gripped so many for the previous half century, often involving questions concerning the proper ways to generate reliable knowledge.

Questions of this sort have long been associated with Newton, for he is often thought of as having refused to admit hypotheses, Unlike Hooke or Huygens—or that great world-maker Descartes—Newton is said to have remained extraordinarily wary of conjecturing explanatory structures that were not strongly connected to the empirical world. His most celebrated remark about hypotheses appeared for the first time in the General Scholium appended to the second edition of the Principia (1713), and remained unchanged in the third edition (1726):

I have not as yet been able to deduce from phenomena the reason for these properties of gravity,¹³ and I do not feign hypotheses. For whatever is not deduced from the phenomena must be called a hypothesis; and hypotheses, whether metaphysical or physical, or based on occult qualities, or mechanical, have no place in experimental philosophy. In this experimental philosophy, propositions are deduced from the phenomena and are made general by induction. The impenetrability, mobility, and impetus of bodies, and the laws of motion and the law of gravity have been found by this method. And it is enough that gravity really exists and acts according to the laws that we have set forth and is sufficient to explain all the motions of the heavenly bodies and of our sea.¹⁴

More has likely been written about this single passage than about anything else that Newton ever did. Yet only in the past few decades have scholars come to understand fully what Newton meant, and how his very public disdain for hypotheses connects with his experimental work and with his development of mathematical theory.

The roots of Newton’s attitudes and methods in respect to experiments and hypotheses reach back to his years as a student at Cambridge; it was here that Newton evolved his own way to merge mathematical structure with experimental investigations—a way that, he would soon discover, was neither congenial nor fully comprehensible to many of his contemporaries. Here especially lie the origins of Newton’s skepticism concerning human perception, as well as his concomitant attention to aspects of measurement that few at the time had probed. This attitude, together with the data-handling techniques to which it gave rise, had a profound impact upon Newton’s manipulation of matters chronological and upon contemporary reactions to it.

The natural philosophy curriculum that the young Newton encountered at Cambridge in the early 1660s had for some time incorporated a great deal beyond the traditional structure of scholastic learning. The novice would begin with a comparatively short introduction to the elements of the Aristotelian system, but he would also soon be introduced to novel developments, such as the works of Pierre Gassendi. Shortly after arriving, Newton bought a bound book with blank leaves to record notes about his studies.¹⁵ This Trinity notebook is dated June 1661 on the front flyleaf.¹⁶ Newton began by inserting passages in Greek, with marginal headers in Latin, from Aristotle’s Organon, and Poryphry’s Isagoge.¹⁷ He continued with Johannes Magirus’ Physiologiae peripateticae, a widely used compendium of scholastic material on causality, physics, and cosmology. The notes break off near the end of Magirus’ fifth chapter, entitled De meteoris apparentibus, and are followed by a very different set on astronomical matters, beginning with Galileo’s estimate of apparent stellar diameters.¹⁸ The notes continue with Aristotelian ethics, also drawn from the Opera Omnia, and then the ethics of Eustachius of St. Paul. Newton’s most extensive notes were on Daniel Stahl’s Axiomata philosophica (1645), which is concerned exclusively with core Aristotelian topics such as act and potency, the typology of causes, agents, and patients, and so on. While Magirus’ text, as its title suggests, concerns natural specifics, Stahl’s provides the fundamental terms of Aristotelian metaphysics. The traditional material ends with Vossius’ rhetoric.¹⁹

For the most part, Newton’s pages on the Magirus and Stahl texts are student notes with little specific commentary.²⁰ They do not necessarily reflect his developing views at this time, much less Newton’s later understanding of related matters, but they do show that he had a reasonable grounding in scholastic materials. Westfall had good reasons to remark that this was the first sophisticated system Newton met, and there is no reason to think that it failed to impress him initially as he emerged from his intellectual provinciality.²¹ Nevertheless, there are signs even here that Newton was not engaging as deeply as, say, a somewhat older Galileo had, with the intricacies of peripatetic doctrine.²² In his early notes Galileo had grappled at some length with the question of whether the heavens are formed of the same stuff as the (Aristotelian) elements; more to the point, he had delved as well into the complex arcana of Aristotelian forms in respect to heavenly bodies.²³ In so doing, Galileo followed the standard structure of a disputation, presenting the claim, then intricate arguments pro and contra. Newton in contrast expended few words, coming right to a bald statement, such as A heaven … has matter that is not fiery … Its motion is simple and circular, natural by analogy … in the sense that it has a natural aptitude to be moved in this way by an intelligence, so the intelligence is similar to a nature. Indeed, the very brevity of Newton’s summary, remarks one historian, conceals problems he has glossed over, and thus leads one to question the depth of his understanding of this problematic subject matter.²⁴

Which is precisely the point. The only pages we have that concern Newton’s studies of such matters do not show us a young man gripped by the power of a system to follow its many elaborate byways. Quite the contrary. Newton’s absorption of scholastic material bears every sign of having been superficial, though in this he was likely little different from the majority of his contemporaries, given the much wider latitude of studies at both Cambridge and Oxford by his time. The young Galileo grappled intimately with Aristotelianism, but there is hardly any evidence to show that, nearly three-quarters of a century later, the young Newton did.²⁵ The difference is telling, because during the intervening decades alternative systems had taken shape, which, though different from one another, were nevertheless grounded on a common epistemology that diverged from scholastic understanding of human knowledge.

The philosophy that Newton encountered at Cambridge in the works of Stahl and Magirus, and probably in discussion as well, was certainly not identical with medieval scholasticism, but the late sixteenth and early seventeenth centuries had seen a revival that emphasized Thomistic Aristotelianism.²⁶ Renaissance humanists had long before criticized scholasticism for its concern with the formal structure of logic,²⁷ and varieties of Platonism, sometimes coupled to Hermeticism, too.²⁸ Though the new philosophical currents associated with the names of Galileo, Gassendi, Descartes, and Hobbes were widely discussed and taught at both Oxford and Cambridge quite early on, nevertheless students were expected to absorb the language and structure of Aristotelianism, which was after all a stable, systematic, and highly evolved system. Indeed, the very terminology and argumentative structure of the new philosophies of the seventeenth century were couched in ways that required knowledge of the scholastic alternatives. I begin with the philosophy of the schools, wrote Ralph Bohun of New College to John Evelyn, which though I make it not my creed … yet since Aristotle has so universally obtained in all the universitys of Christendome for so many ages [and] thus insensibly crept into all modern writers by the use of his terms, it’s almost impossible, as things stand, to be either divine, physician, or lawyer without him … how then can it be expected that we should understand the new philosophies without him, when the greatest part of their works consist only in confutation of his.²⁹

Among the most fundamental of scholastic doctrines, and certainly one that could not be missed by even a cursory reader, was hylomorphism. For scholastics an entity consists of a material substance, or hule, which is conjoined to two kinds of form, or morphe. Forms are, very loosely, the characteristics of a given entity. Matter does not exist in the absence of form, and neither does form exist in the absence of conjoined substance.³⁰ There is, at the most fundamental level, an object’s substantial form, which makes it a particular this rather than a that. A horse’s substantial form differentiates it from the substantial form of a donkey. There is, in addition, accidental form, which does not alter the essence of an object but which may characterize a particular entity at some particular time. A piece of wood may be painted brown one day and blue the next, but it remains a piece of wood: color is not an essential part of its being a piece of wood. This way of thinking entailed a specific understanding of the process of cognition itself: of how knowledge of things comes about. In scholastic cognition, an object’s accidents are brought to bear upon the sense organs through any of various means, including direct contact. However it occurs, the entity’s form produces in the sense organ, proximately or directly, a change: a quality known as an intentional species, particular to the form in question.

Hatfield concisely describes the next steps. The species is received by a sensory power in the percipient, which is thereby

actualized to its characteristic sensory activity … in the act of sensing, a kind of identity arises between the sensory power and the object sensed, which identity permits the power to be directed toward or attentive of the object, and so to cognise it … The common sense discriminates among the objects of the special senses (e.g. it discriminates white from sweet). The species received by the external senses are retained as phantasms³¹ in the internal senses. These phantasms are corporeal in nature; that is, they are states of the corporeal organs informed by the sensitive power of the soul … Cognition of the natures or essences of bodies requires intellection. The immaterial intellect illuminates the phantasm and abstracts the essence or common nature of the represented thing. [And then] the agent intellect, together with the phantasm produces an (immaterial) intelligible species in the patient or possible intellect. Reception of the patient intellect completes the act of understanding.³²

Perception itself, wrote Aristotle, of the special objects of sense is never in error or admits the least possible amount of falsehood.³³ He meant that the forms that activate the correctly operating sense organ are always perceived as qualities that are, qua forms, the same as those of the perceived entity from which they arose. However, the entity whose form or forms these qualities originated from may be incorrectly imagined as such. So, for example, while the perception that there is white before us cannot be false, the perception that what is white is this or that may be false.³⁴ Imagination is the faculty by means of which the activated qualities of sense organs produce knowledge of objects. Common to both beasts and humans, imaginations remain in the organs of sense, i.e., they are not functions of the soul.

There were many intricate issues over which scholastics had long chewed concerning these matters, involving in particular questions concerning the manner in which an entity, not in direct contact with the sense organ, can engender its form. To that end, late scholastics carefully distinguished two ways in which forms may exist. They may exist, as it were, bound to an entity’s natural material being. Or they may exist as forms connected to an entity’s matter but without a corresponding natural binding, which allows the matter to carry the form without the corresponding quality characterizing the matter which bears it. These latter sorts of forms are intentional, and they are (among some late scholastics) what affect the sense organs, which are therefore not in themselves characterized by the forms in question—an eye that yields the perception of red does not itself become red but does bear the intentional species of redness that the original (red) object impressed upon the air between itself and the eye, with the air carrying the form only intentionally and not naturally. Issues of this sort date back to the thirteenth century, but, intriguingly complex though they were, scholastics all held that qualities as such come to bear on the sense organs.³⁵

Scholastic cognition accordingly involves a tight connection between perceiver and perceived, one in which the perceiver’s sense organs are activated, in most cases via intermediaries, by the forms that endow the object’s substance with those characteristics which the sense organ’s own qualities adapt it to receive. When for example we stroke a soft, furry thing, our sense of touch receives its softness and furriness; our sense of sight receives the redness of a ripe apple, our sense of taste the sweetness of sugar. The perceived entity does not induce changes in the sense organ that merely correspond to the form in question; it produces instead an effect that is specific to the form itself and that can be produced in no other way if the sense organ is in proper working order and the body is not otherwise active.³⁶

Magirus’ text, over four hundred pages long, consists of six books, on four of which Newton took notes.³⁷ Stahl’s contained twenty-two titles and ran to seven hundred pages. Both provide ample discussion of issues concerning matter and form, with Magirus investing the scheme in specific instances.³⁸ Moreover, Magirus’s account of perception, based primarily on De Anima, was extensive, consisting of fifty-nine propositions followed by a commentary. It provides a good, concise account of the scholastic understanding of perception that we have just outlined. Newton, however, took no notes at all on Magirus’ sixth book, which contains the account. Neither is there anything in Stahl on the subject. While Newton was accordingly introduced in some detail to Aristotelian physics and metaphysics, he may not have encountered—he certainly took no notes on—the complex issues concerning cognition that are treated in De Anima. Neither do Newton’s notes show him to have been gripped in any substantial way by Aristoteliana, for his notes are mostly uncommented précis of the two texts. These are not the reflective remarks of someone who was interested in exploring the intricacies of scholasticism.³⁹ Newton may have drawn on elements in the standard vocabulary and conceptions of the period, using them as resources to forge his own notions,⁴⁰ but there is simply no evidence in the notes on Magirus and Stahl to suggest that Newton was doing anything beyond the normal note-taking of a Cambridge student.

Stahl and Magirus were hardly the only texts with which Newton grappled, for the Questiones, though (perhaps significantly) later than the Aristotelian material in the notebook, plunge deep into the worlds of the new philosophies. The Questiones are dated by the notebook’s editors to, at the earliest, the summer of 1663 (or perhaps even spring 1664).⁴¹ Newton continued to enter remarks until early to late 1665, treating topics ranging from motion and atoms to light, gravity, and comets. Throughout these pages Newton repeatedly turned, apparently for the first time, if we may judge by their absence from his Aristotelian notes, to connections between the senses, matter, and the soul. Furthermore, in the texts that prompted these notes—and, we shall see, his engaged reflections—Newton encountered an often-corrosive anti-scholasticism.

Evidence from the Questiones shows that Newton was acquainted with, and in at least some cases carefully read, works by Boyle, Walter Charleton, Descartes, Kenelm Digby, Galileo, Joseph Glanville, Henry More, and Thomas Hobbes. He knew Boyle’s Spring of the Air as well as his Experimental History of Cold, and—especially—Boyle’s On Colours. He also knew Charleton’s sarcastic and vigorously anti-Aristotelian presentation of Gassendi’s Epicurean atomism, the Physiologia; Digby’s Two Treatises, which mixed Aristotelian with Cartesian elements; Galileo’s Dialogue (but not, most likely, his Discourses); Glanville’s Vanity of Dogmatizing, which dissolved all secondary causes into the activity of the deity; Descartes’ Opera philosophica; Hobbes’ thoroughgoing materialism in his De corpore; and Henry More’s critique of both Hobbes and Descartes, with its efforts to reinsert spirit into space.⁴²

The very first pages of Newton’s Questiones, headed Of the first matter followed immediately by Of atoms, reflect his reading of Charleton and of More.⁴³ Newton grappled with several arguments raised in Charleton’s thoroughgoing atomism. Though he did not take notes on other material in Charleton’s text, even a quick perusal of the Physiologia would reveal Charleton’s attitude toward Aristotelianism. One example drawn from many nicely illustrates the tone of his rhetoric. The despot of the schools, as he at one point called Aristotle,⁴⁴ assimilated sapours (taste) to the unacceptable principles of hylomorphism, so that "the extreme slenderness of his doctrine, touching the essence and principles, of sapours as well in general as particular; erected on that common imaginary base of immaterial qualities, hath given us occasion to suspect the solidity of his inference or conclusion; and left us cause to account that sentence, much more canonical, that things most manifest to the sense, often prove most obscure to the understanding.⁴⁵ Indeed, Aristotle’s endeavours afford so dim a light to our profounder inquisitions, as to leave us in the dark of insatisfaction. Though he deployed the common terminology of causes, including the formal, throughout his various discussions, Charleton aimed to cut quality away from its hylomorphic seat, and to replace it with the physical actions of atoms striking the organs of sense. In discussing vision, though Charleton disagreed with the excellent Monsieur Descartes concerning the nature of light proper, he fully adopted the account of vision itself. The throne of the mind, Charleton remarked, judges the nature of the object … only by the variety of strokes given to the external organ [the eye], thence to the filaments of the nerve annexed thereto, thence to the presence chamber of the soul: we are informed of the particular qualities, and conditions of every sensible; the variety of these sensory motions being dependent on the variety of qualities in the object, and the variety of judgments dependent on the variety of motions communicate.⁴⁶ Digby, to whom Newton referred briefly in of touching,⁴⁷ and who was neither atomist nor Cartesian in respect to material substance, nevertheless also rejected hylomorphism, remarking that the sensible qualities of bodies are not any positive real thing, consisting in an indivisible and distinct from the body itself but are merely the very body, as it affects our senses: to discover how they do, which must be our labour here.⁴⁸ He too, approved Descartes’ great and heroic attempts to explicate the nature of sense, agreeing that by the great variety of knocks or motions that our brain feels (which rises from as great a variety of natures in the objects that cause them), we are enabled to judge of the nature and conditions of every thing we converse withal."⁴⁹

Hylomorphism accepts, indeed it embraces, an association between a form of an entity and a related formal property of the sensing organ. Mechanism, whether Cartesian or atomist, cannot do anything like this because qualities, properly speaking, exist in perception but not in the unperceived world. The Gassendian and Charletonian atoms that leave an entity and strike the senses engender the sequence of mechanical effects that lead ultimately to the perceiving mind’s construction of the entity’s qualities, but these qualities, as such, require perception for their very existence.⁵⁰ Mechanical philosophies of the seventeenth century, including renovated and theologically purified Epicureanism, accordingly break the link between a percept and an entity’s property: even, e.g., shape must somehow be constructed by the soul or mind out of stimuli that in themselves are related to the entity’s physical characteristics only through a chain of mechanical effects. This is the central problem with which mechanists had to grapple, with all of its ancillary difficulties, not least theological.

Scholastics certainly did think that the organs of sense might be active in ways that do not, or do not any longer, match the form of the originally stimulating entity. This can occur because even when the external object of perception has departed, the impressions it has made [on the sense organs] persist, and are themselves objects of perception.⁵¹ Aristotle provided an apposite example, akin to one to which, we shall see, the young Newton paid especially close attention: if, after having looked at the sun or some other brilliant object, we close the eyes, then, if we watch carefully, it appears in a right line with the direction of vision (whatever this maybe), at first in its own color; then it changes to crimson, next to purple, until it becomes black and disappears.⁵² Further—the primary aim of Aristotle’s account in De Somniis—the stimulatory movements⁵³ based upon sense perceptions, whether the latter are derived from external objects or from causes within the body, present themselves not only when persons are awake, but also then, when this affection called sleep has come upon them, with even greater impressiveness.⁵⁴ Alternatively, there might be a complete mismatch between a stimulating entity and the perception induced in an organ of sense if the organ is not functioning properly—if, that is to say, the form activated in it does not correspond to the form of the activating subject, as when the hand mistakenly senses an intensely cold object for a hot one, having as it were been damaged by the intense cold.

The percepts that arise in the Aristotelian sense organ are, we noted previously, never in error: they are what they are and cannot be otherwise; the percept green is simply what it is, though the formal property of the eye that is the percept may not have been activated by a correspondingly green subject. Mechanical philosophers would certainly agree with the inerrancy of the senses in this meaning, and they would further agree that the same percept can be engendered by an entity’s persisting effect on the organ as well as by its immediate action, or by causes internal to the organ itself. However, because they rejected the hylomorphist match between the forms of (properly working) sense and of the stimulating entity, mechanical philosophers also had a subtly different understanding of the errors to which the senses may give rise even when they are working correctly and contemporaneously with the engendering subject.

For the scholastic, a correctly operating sense organ possesses an activated form that necessarily matches the form of the external entity. The organ’s form does not just come close to complementing the latter’s property; the two are indissolubly united. Not only is the percept induced in a sense organ inerrant by its very nature, so must be the connection between the percept and the form of the stimulating subject, provided only that the organ is functioning properly. The reason for this lies deep within Aristotelian metaphysics, which does not break apart the perceived from the perceiver. If the sense organs are working well, then the percepts to which they give rise must directly match qualities that are the same ones that characterize the subject of perception. The imagination may err under certain circumstances as to the subject that produces the percepts, as when a circle seen edge-on with one eye may be perceived as a line, but this is the result of the senses not operating in conjunction with one another, for imagination is a result of their joint action.⁵⁵ The scholastic’s eye, ear, smell, taste, or touch either operates properly, in which case it correctly captures the form of the stimulating subject, or else it does not. No via media crosses between the properly working and the faulty sense, and for just this reason scholastics did not have to face the problems of epistemology that arose with mechanism.

The sense organs of mechanical philosophy, unlike those of scholasticism, could not be said meaningfully to reproduce or to match the qualities of the external entity. Neither did mechanists locate percepts in the organs themselves, as Aristotle had. They certainly did envision links between the motions of the entity and the engendered motions of the sense organs, but the connections had to be purely mechanical and not ones of formal identity, because motion meant only one thing, namely the change of spatial relations between qualitatively unalterable parts. Error creeps ineluctably into the mechanically engendered perception because the sense organs are akin to instruments like the telescope or even the ruler and compass, differing from them in only one critical respect: unlike the devices of the natural philosopher, the sense organs produce motions that are transmitted by the animal spirits through the nerves and thence to some region of the brain.⁵⁶ And just as no craftsman can make an instrument to any desired level of perfection whatsoever, neither can the organs of sense achieve a perfect match between the motions produced in them and the originating movements in the external world. Vibrations engendered in the ear by a sounding entity cannot for example perfectly match the entity’s, any more than one thing can force another to move in flawless mechanical harmony along with it. Perfect harmonious motions can occur only at the level of elementary interactions between the underlying mechanical bits and pieces that constitute the world, but not between the furniture of the perceived universe which is forged out of them. Only a Gassendian atom, or a microscopic Cartesian volume, can nicely equal another atom’s or spatial bit’s movement. The mechanist’s perceived world must accordingly differ from its natural progenitor even when the organs of sense work as well as they possibly can. And so inevitable error stalks the sensed world of the mechanical philosophy, whereas harmony between perception and subject governs the universe of healthy scholastic sensation.

By the late sixteenth and early seventeenth centuries, a devotee of form could nevertheless dispense with the apparatus of formal transformation that undergirded fully fledged hylomorphism. The atomist Daniel Sennert’s explorations of alchemical processes were grounded both in his conviction that forms do exist and that they do not transform. Sennert himself, notes William Newman, did not view substantial forms as an unfortunate but necessary consequence of scholastic hylomorphism—rather, they were active witnesses of God’s power and beneficence in the world … Sennert’s explanation of chymical reduction locked the forms safely within their material vehicles, the atoms, and allowed them to persist in the face of the technological assault stemming from those striking agents of qualitative change, the mineral acids … From Sennert’s perspective, then, his atomism had saved the substantial form from the unworkable theorizing of an excessively metaphysical type of Aristotelianism that mired itself in speculation to the detriment of evidence.⁵⁷ Forms could be allowed, even insisted on, but only so long as they no longer served any functional role. All qualities flow from form, Newman continues of Sennert, and yet the opaque and shiny tint of silver disappeared when the metal dissolved into a clear solution in nitric acid, as he observed no less astutely.⁵⁸ Moreover, during the century even the dominant scholastic position became somewhat more dualistic than hylomorphic, with matter being endowed with being, while another trend—perhaps in the opposite direction—was the shifting of one of the principal functions of matter [individuation] to form.⁵⁹

Conservative hylomorphs nevertheless did not evaporate, even as scholastic terminology was twisted and broken into the frameworks of mechanism. Existing words and syntax are rarely, if ever, abruptly dropped, for they constitute the substance of conventional speech; new ways of talking evolve within an older universe of expressions, with discursive slippage, overlap and inconsistencies only gradually sorting out. Many did not lock forms away in Sennert’s fashion, and neither did they transmogrify matter and form into space-filling substance and shape. Consider for example the 1672 essay of the Jesuit, Antoine Rochon, in a letter to a Cartesian among his friends. Rochon’s prime concern was a common one among Catholic theologians throughout the seventeenth century, namely that the Cartesian world was difficult, and perhaps impossible, to reconcile with the demands of transubstantiation.⁶⁰ Rochon’s theological issues with Cartesianism orbited about the issue of matter and form. He pointed out, with good reason, that Descartes’ mechanisms were purely hypothetical, that "if I ask you [a Cartesian philosopher] what is that certain figure, that certain manner, that certain juice, and those certain parts, you have nothing to tell me that you didn’t already