To the eighteenth-century adherents of the new age of science and reason, descendants of the moderns we have discussed, the greatest hero of this new age was Isaac Newton. They saw in his work the triumph of the long struggle waged by Copernicus, Galileo, and so many others to establish a view of the cosmos founded on observation and reasoning rather than dogma and superstition. Modern students paint a more complicated picture of the very lively world of science that nurtured Newton’s achievements in optics, mechanics, astronomy, and mathematics. We must still stand in awe, though, of the powers of mind and concentration that finally led to formulations—for which Newton himself had invented much of the mathematics—that remain basic to our understanding of nature. His most dramatic achievement was his synthesis of the universal law of gravitation. Here he followed his mathematical reasoning away from commonsense observations that things affect one another through direct contact toward a concept of action at a distance with which he remained uneasy and for which he could give no intuitive, commonsense explanation. After decades of vehement controversy the whole world of science eventually followed him.
The year 1688 was an extraordinary time in Newton’s life. After decades of projects started and stopped, and near-paranoid reactions to mild criticisms, in 1687 he had pushed a major work through to publication. Not just major but one of the few books that have really changed how we all see the world, Philosophiae Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy). Its epochal importance was immediately proclaimed in reviews. At the same time the English political crisis had begun to bring him out of his apolitical solitude. He was on his way to being a public man for the rest of his life.
Newton was born in 1642 to a prosperous but unlettered family in a Lincolnshire village. His father died before he was born, and when he was three, his mother remarried. The boy was left with his mother’s parents until the stepfather died seven years later; it is probable that this wrenching separation from his mother was one of the prime sources of his later mental instability. His mother’s family, especially her clergyman brother, urged that the very bright and very strange boy get a solid education, especially after he proved to be an absentminded disaster on the farm. He made many sundials; all his life he had an accurate and attentive sense of the movements of the sun and of shadows wherever he was. In 1661 he entered Cambridge University. Little science or mathematics was taught, and he learned less from his formal studies than from the books he bought. In 1669 he was circulating essays in manuscript containing the basics of his invention of the calculus and was named Lucasian professor of mathematics at Cambridge. By 1672 he had been elected to the Royal Society and had published a paper in its Philosophical Transactions showing that white light was composed of many different colors, which could be differentially refracted by a prism. But his furious reaction to mild criticism by the pathbreaking physicist Robert Hooke led to his virtual withdrawal from interaction with other scientists into the study of alchemy.
For the next several years Newton copied and annotated alchemical treatises. He assumed that various old and new intellectual traditions might contribute to uncovering hidden truths, and he tended to follow one tradition at a time with monomaniacal concentration. Newton was interested in alchemy not as a quest for transmutation of “base metals” into gold but as a path to hidden truths about the principles of attraction among things. Alchemical symbols of light and the sun encouraged his speculations about an original and pure form of worship, in the Temple of Solomon and the ancient temples of Egypt and Greece, in which a flame at the center of the holy space represented the sun, “an emblem of the system of the world.”
These speculations kept Newton on the trail of hidden realities that could be analyzed quantitatively. He had developed his basic quantitative explanation of planetary orbits a decade before; Hooke now mentioned his own vague hunch in that direction. Later, when Newton followed it up with mathematical rigor, Hooke accused him of plagiarism, and the old antagonism briefly threatened to derail publication of his great book. Then in 1684 Newton had a fruitful encounter with a generous colleague. Edmond Halley, hard at work on an effort to explain the orbit of a comet that had appeared in 1682, which we still call Halley’s comet, came to see him. Newton said he had worked out the derivation of an elliptical orbit from his basic mathematics of orbits. Halley was astonished; this was just what he needed. He encouraged Newton to write up his calculations and in three months received a short tract, “On Motion.” Newton went on expanding and refining his results, wholly absorbed, often forgetting to eat his meals. He found the full development of his ideas was “a thing of far greater difficulty than I was aware of.” He formalized his three basic laws: inertia, the proportional relation between changes in motion and the force exerted and the equal and opposite reaction to every action. He had had several pieces of the law of universal gravitation for a long time, but it was only now that he brought them together in a rigorous way. Moreover, he even made his orbital calculations work for comets.
In 1686 Halley had enough manuscript in hand to propose to the Royal Society that it undertake the printing of the work. The society agreed but later insisted that Halley, who was not a rich man, be responsible for paying the printers. When Hooke claimed that Newton had plagiarized his work, Newton threatened to withdraw a key part of the work, but Halley managed to calm him down. Newton had a completed work, a publisher, and a most loyal friend; nothing could stop him now. Halley pushed on, working long hours on the details of the formidable diagrams and on the proofreading. Finally on July 5, 1687, he reported to Newton that the book was done and sent him twenty copies. As Newton walked down a street in Cambridge, a student was heard to say, “There goes the man that writt a book that neither he nor any body else understands.”
The reviewers understood. Halley wrote the review for the Philosophical Transactions: “This incomparable author . . . has in this Treatise given a most notable instance of the extent of the powers of the Mind; and has at once shewn what are the Principles of Natural Philosophy, and so far derived from them their consequences, that he seems to have exhausted his Argument, and left little to be done by those that shall succeed him.” Early in 1688 the Acta Eruditorum published a long and admiring summary, and the Journal des Sçavans called it “the most perfect mechanics one can imagine” but argued strenuously against the basic concept of action at a distance.
By then Isaac Newton was deeply embroiled in the crisis of relations between his university and James II. In 1687 the king had ordered the university to admit as Master of Arts a Benedictine monk who clearly planned to participate in university affairs. There was some resistance, and in March Newton, virtually done with his work on the Principia, emerged as one of its leaders. In April he played a major role in drafting the statements of eight delegates who appeared before a formidable Ecclesiastical Commission, presented the university’s argument against giving the Benedictine an M.A., and surprisingly got off with nothing more than a lecture. We have almost no evidence about his life in 1688. He was suing his tenants for failure to maintain the farm he had inherited, the same farm on which he had been such a disaster early in life. In January 1688 he wrote a detailed letter about the conditions he found on the farm on a brief visit in March and April 1687. On the whole he probably was lying low, hoping the political storm would blow over, and reading his reviews.
In 1689 Newton was one of two delegates from the university to the Convention Parliament. He met Locke and many other important people. In 1690 he was named warden of the Royal Mint. He took the post seriously and helped send several counterfeiters to the gallows. He finally published his work on optics done long before, was elected president of the Royal Society, worked on improvements on the Principia, and got into a furious controversy with Leibniz over priority in inventing the calculus.
John Locke spent all of 1688 in Holland, most of it lodging in the house of his good friend Benjamin Furly on the Shipwrights’ Harbor in Rotterdam. Furly was a prosperous Quaker merchant who had lived in Rotterdam since about 1660, when the Restoration had made England uncomfortable and often unsafe for people of his convictions. In 1688 Furly was spending some time petitioning Prince William on behalf of an Anabaptist preacher who had been hounded out of his native province by the Calvinist preachers and now was being threatened with expulsion from a town near Haarlem. For Locke, who had fled England in 1683, the Furly house was a refuge among people who shared his love of liberty and some degree of his love of books and curiosity about the world. Most important, the aging bachelor scholar found in the Furlys something like a family. Locke’s letters to Furly when he was away are informal and chatty and never fail to send greetings to Mrs. Furly and to their youngest son, Arent, born in 1685. The boy’s name was Dutch, and although Locke almost never wrote in the language, he used fragments of it in his greetings to the little boy: “Tell Toetje [Arent] I send this message that if he continue to be stout [Dutch for naughty] I will bring him nothing and that when I come Jantje [Jan, an older brother] shall be my friend and he no more.”
Locke saved every piece of writing that came into his hands; the modern edition of his correspondence contains 105 letters from the year 1688, from Locke, to him, and a few others from and to close friends and annotated in his hand. Many of them contained praise for either the manuscript copies of his Essay concerning Human Understanding that were circulating among a few patrons and special friends or the printed copies of a French synopsis of the Essay that had just been published. Locke and his friends recognized that this long, complex book would make his reputation. They could not have suspected that it would shape Western thought for hundreds of years to come. Building on Descartes’s questions about the nature and reliability of our ideas and Hobbes’s first steps toward a causal account of human knowledge, Locke laid out the fundamentals of an empiricism, a unified account of the origins of our experience, that we still find plausible even when we know how to criticize it. Locke investigates perception and introspection as sources of knowledge and argues against any theory of innate ideas. He shows sensitivity to the ways our reasoning is led astray by language and an interest in how we acquire our ideas. This interest leads him to observation of infants and children and consideration of the physiology of perception. He argues against reifying concepts like “substance” that can’t be readily explicated in empirical terms. In this the Essay was, and was rightly understood to be, a major attack on the foundations of earlier religious orthodoxies and some proofs of the existence of God. In years to come Locke, despite his own deep conviction of the moral necessity of religious belief and the possibility of demonstrating the existence of God, was drawn into vehement controversy with the guardians of orthodoxy.
In his Dutch exile in 1688 Locke’s thoughts turned regularly to another work that had not yet been published and that he hoped no one was reading. In writing to the trusted relative who was hiding it for him he referred to it by the code name De Morbo Gallico, a nice joke. “The French disease” was a euphemism for syphilis, and Locke as a medical man might be expected to have a book about it; Locke and many others thought of royal absolutism as a French disease. The manuscript was Locke’s explosive justification for resistance and rebellion against tyrants that was to be published in 1689 as Two Treatises on Government. Most of it had been written about 1680, and Locke made a few additions to fit the 1689 situation. It began with an extended attack on the prevailing theories of royal absolutism and went on to develop the famous theory of the state of natural equality and autonomy of men and how men “by their own consents . . . make themselves members of some politic society.” Either the state of nature or that of society might turn into a state of war when one man attacks another or seeks to get him under his absolute power. “He that in the state of nature would take away the freedom that belongs to anyone in that state, must necessarily be supposed to have a design to take away everything else, that freedom being the foundation of all the rest; as he that in the state of society would take away the freedom belonging to those of that society or commonwealth, must be supposed to design to take away from them everything else, and so to be looked on as in a state of war.” In a state of society private property is justified because individuals add labor to land or materials and have a right to the products of their labor. The protection of property is one of the chief goals of civil society. It is those who violate the constitutions and laws of a society who are the true rebels and must be dealt with as such. Developed to justify resistance against the absolutist policies of Charles II, updated to justify after the fact the rebellion against James II, far more radical in its implications than the moderate commitments and cautious temperament of its author, this famous work became a foundation of revolutionary thought in America and of much modern democratic thought. It was published anonymously in 1689, and although knowledge of Locke’s authorship soon was fairly widespread, he acknowledged it only in his will.
Other sides of Locke appear in his correspondence with an English country squire named Edward Clarke, whose wife, Mary, was Locke’s cousin. Landless, a bachelor, living in exile, Locke projected onto the Clarkes his frustrated domestic and landholding impulses, sending them saplings for their house, where some of the resulting trees survived past 1900. Early in 1688 he sent Clarke some fine Friesian sheep to improve his herd. Since 1686 Locke had been writing long letters to Clarke about the education of the latter’s son. These thoughtful letters, eventually published as a book, Some Thoughts concerning Education, make Locke one of the founders of educational psychology as well as modern empiricism and liberalism.
On February 6, 1688, Locke wrote to Clarke, “The thing, then, that I am going to say to you is, that I would have your son learn a trade, a handicrafts trade. Will you not think now, that I have either forgot that he is your eldest son and heir, and have formerly written to you concerning his education, which all had a tendency to a gentleman’s calling, with which a trade seems wholly inconsistent. I confess that so, and have not forgot either his birth or estate, or what breeding I thought suitable to it. . . .” Should the boy take up painting? No, for it will be of no benefit if he has no talent for it; “ill painting is one of the worst things in the world.” Gardening and working in wood would be better, particularly since both are of immediate use to a country gentleman, in doing things for himself and in supervising his servants. “The skill should be so to employ their time of recreation that it may relax and refresh that part which has been exercised and is tired, and yet do something, which, besides the present delight and ease, may produce something which will afterwards be profitable.” Finally he decides that the best trade for the boy to learn would be that of a jeweler. By working with a jeweler in Holland or another foreign country for a year or two, the boy would learn an exacting craft that can yield a good livelihood and brings the craftsman in contact with “persons of quality” and would have the experience of living abroad without the usual frivolous and dependent touring. Whatever the trade, the point is, in this and in the rest of the young man’s education and life, to give him variety of activity, for “children hate to be idle. All the care then is, that their busy humor should be constantly employed in something of use to them.”
In another correspondence Locke’s lonely humanity takes on deeper colors. Damaris Cudworth, Lady Masham, wrote to Locke from Oates, her country house in Essex, on April 7, 1688, to comment on the French summary of the Essay concerning Human Understanding. She particularly took issue with Locke’s opposition to any version of the theory of innate ideas. She thought Locke had exaggerated the differences between his own views and those he attacked. Proponents of innate ideas did not claim that they were “legibly writ there like the astronomical characters in an almanac; but only an active sagacity in the soul whereby something being hinted to her she runs out into a more clear and large conception; her condition being that of a sleeping musician who does not so much as dream of, or have any representation of anything musical in him, until being waked and desired to sing, somebody repeating two or three words of a song to him, he sings it all presently.”
The musical metaphor, the use of the feminine for the soul, the assertion of a form of the doctrine of innate ideas all are signs of someone schooled in the tradition that called itself Platonic. Damaris Cudworth was the daughter of the Cambridge Platonist Ralph Cudworth and apparently received most of her education from her father. When she and John Locke met in 1682, she was twenty-four and he was fifty. She fell in love with him, but at first he could offer no more than friendship. By the time his ever-cautious feelings warmed, she was too disappointed and hurt to respond. They probably still had not entirely sorted out their feelings when Locke fled the country in the summer of 1683. Their letters continued in a mixture of deep and wary affection and wide-ranging intellectual discussion. But in an age when every woman was expected to marry at a fairly young age she could not be expected to wait for him forever. In 1685 she married Sir Francis Masham, a widower with nine children. In subsequent letters she had a great deal to say about the busyness and dullness of her life in the country. Near the beginning of her April 1688 letter she wrote, “You are indeed in the right to believe that I do not practice all the rules of the neighborhood, and that my kitchen and dairy do not engross all my time.”
Locke returned to England in January 1689, to a pleasant degree of fame and influence as the intellectual godfather of the Glorious Revolution. The smoke and fog of London were not good for his lungs, and soon he began to take refuge at the house of Damaris and her husband in Essex. From 1691 on it was his principal residence. Damaris was with him when he died in 1704.
Gottfried Wilhelm Leibniz, philosopher, mathematician, legal scholar, historian, zealous proponent of the reunion of the Christian churches, expert on mines, coinage, and taxation, state councillor of the duke of Brunswick-Lüneburg, spent all of 1688 away from Hannover, the capital of his master. Traveling in his own coach, followed by his own baggage wagon (about half full of books, one suspects), he was pursuing information on the genealogy of the House of Brunswick-Lüneburg, information that was to lead in 1692 to its elevation to the status of electoral princes of the Holy Roman Empire. Seeking old records in cathedrals, monasteries, princely libraries, and private collections, he was able to indulge all his other interests, viewing collections of natural curiosities, discussing mining and coinage with experts, continuing his conversations and correspondences with Catholic, Lutheran, and Calvinist intellectuals sympathetic to his tireless efforts to overcome Europe’s confessional schisms. In rural Bavaria the Lutheran scholar was fascinated by the alien spectacle of the scourging of a man bearing a cross in a Holy Week procession.
Reaching Vienna in May, Leibniz soon obtained access to the Imperial Library and found more important documents for his work. He renewed a cordial friendship with Cristóbal de Rojas y Spinola, Roman Catholic bishop of Vienna-Neustadt, as zealous for church reunion as he was. He also advised the Brunswick-Lüneburg envoy to the imperial court and wrote several policy proposals which he hoped to present to the emperor. He was exploring the possibility of obtaining a position there, as a court councillor, court historian and archivist, and director of an Imperial Institute of History for which he and his scholarly friends already had detailed plans. Finally late in October he was received in audience by the holy Roman emperor Leopold: “I now have experienced the day that I have wished for for many years, when I could offer my most humble devotion to Your Majesty in person.”
The most unusual of Leibniz’s proposals to the imperial court would have literally brought light to the capital. Leibniz’s friend Johann Daniel Crafft already had obtained a concession from the court to assemble materials for the lighting of the streets of Vienna with oil lamps, but it was not clear where the oil could be found without spending a great deal of money or creating shortages for other consumers. But there were newly conquered lands in Hungary that were at the disposal of the emperor. If some of them were assigned to Crafft and his associates, rapeseed could be grown on them for oil, affording them a privileged market in the Viennese streetlighting enterprise. The land also could yield samples of other little-known vegetables and useful crops.
Leibniz is best known as the elaborator of an original metaphysical system of harmonious spiritual substances and as one of the inventors of the calculus. In the mid-1680s he made breakthroughs in both those areas, publishing articles on the basics of the calculus and writing in 1686 a “Discourse on Metaphysics” that is the first important statement of his mature philosophy. Leibniz now saw philosophy as a venture in the interpretation of human meanings that could take religious, moral, and political heritages and convictions as seriously as the rigors of mathematics, physics, and astronomy. Leibniz’s metaphysics of autonomy and harmony reflected constant exchanges of opinions with learned men, his political duties, projects for economic improvement, and above all his great cause of the reunification of Christendom. For him substances had to be spiritual as well as material, capable of free will. He found in each substance some limited reflection of the autonomy and willing power of God, the immortal souls of human beings having the most of this power, inanimate objects the least. In a letter of 1686 he summarized better than at any one point in the “Discourse” the state of his thinking at this time: “I believe that every individual substance expresses the whole universe in its manner and that its following state is a consequence (though often free) of its previous state, as if there were only God and it in the world; but since all substances are a continual production of the sovereign Being, and express the same universe and the same phenomena, they agree with each other entirely, and that makes us say that the one acts on the other, because the one expresses more distinctly that the other the cause or reason of the changes, rather in the way we attribute motion to the vessel rather than to the whole of the sea.” Leibniz had inherited puzzles of rationalist metaphysics and Christian theology, but in his emphasis on the autonomy of each substance, its continuity through time, and above all on the way it mirrors and expresses every other one, he had come to a distinctive vision. It was deeply consonant with his own fascinated affirmation of human variety and his conviction, clear in his philosophical correspondence and his efforts to reunify Christendom, that all individualities were mirrors of one another and of the one Truth.
In 1688 Leibniz was preparing for, but had not yet made, a last amazing leap in conviction that all people can understand one another. He had been drawn to the knowledge of China that was reaching Europe through the writings of missionaries since the early 1670s. Much of his early information had been filtered through learned Germans who had never been to China and whose understanding of it had at least as much to do with their search for a universal linguistic/logical key (an enthusiasm that the young Leibniz shared) as with Chinese realities. In December 1687 Leibniz had seen at Zunner’s bookstore in Frankfurt a copy of the newly published Confucius Sinarum Philosophus, just published that year. It is not clear if he bought it; perhaps it was in that baggage wagon as he continued his travels. He noted that the earliest dates reported in the traditional Chinese chronologies seemed disturbingly close to the date of the biblical Deluge, and he remarked upon the moral and literary quality of Confucius’s teachings: "He ordinarily makes use of similes. For example, he says that it is only in the winter that one learns which trees keep their greenery; and similarly all people seem the same in times of calm and happiness, but it is among dangers and disorders that one recognizes that man of merit and worth.” He sought out Jesuit veterans of the China mission, corresponded with missionaries in China, and dreamed of a great “interchange of illuminations” with the Chinese.
Catholicism, Protestantism, skepticism, dogma, now even Confucianism all became in the eyes of this great man facets of reason, reflections of God. Properly understood, all could contribute, along with reformed coinage, streetlamps, taxes that did not burden the poor, even history, to harmony and prosperity under enlightened rulers. The basic values he sensed in 1687 on his first reading of Confucian texts in translation already were at the core of his own values in his “Philosophical Confession” of 1675: “It belongs then to him who loves God to be satisfied with the past and to exert himself to make the future the best possible; only he who is disposed in this direction arrives at the tranquility of spirit sought by the ascetic philosophers, at the resignation of all to God sought by the mystic theologians.”
I think Leibniz would have been pleased if someone had pointed out to him how much his life in 1688 was like the life of Confucius himself: traveling, seeking the favor of princes, planning for the welfare of the common people, engaging in earnest conversation with good friends, studying history, remaining respectful of religion but a little distant from it. I think he would also have been pleased by the place he occupies in this book, reflecting, like one of his substances, so many facets of the world whose traces we are following: its Manchu and Ottoman empires, its scientific breakthroughs and largely traditional technology, its rootedness in the past and earnestness for conciliation and secular improvement, the dependence and insecurity of many of its finest thinkers, the long continuities and sudden upheavals of European dynastic politics, the individualities of voice and idiosyncrasies of life we still can trace three hundred years later.