required no more of art than to assist nature when she languished, and to check her when her efforts were too violent. . . . For this sagacious observer found that nature alone terminates distemper, and works a cure with the assistance of a few simple medicines, and sometimes even without any medicines at all. 82
Sydenham’s distinction lay in recognizing that each major disease has many varieties; he studied each case with its clinical record, in order to diagnose the special form of the disease involved; and he adjusted the treatment to the specific differences of the ailment. So he separated scarlatina from measles, and gave it its current name. He was known to his profession as “the English Hippocrates,” because he subordinated theory to observation, general ideas to particular cases, and drugs to natural cures. His Processus Integri remained for a century the English practitioner’s manual of therapy.
Surgery continued to struggle for recognition as a reputable science. Its ablest representatives found themselves pressed on either side by the hostility of physicians and the envy of barbers—who still performed some minor operations, including dentistry. Guy Patin, dean of the faculty of medicine in the University of Paris, could not forgive surgeons for assuming the dress and manners of the medical profession, and he denounced all surgeons as “a race of evil, extravagant coxcombs who wear mustaches and flourish razors.” 83 But in 1686 the surgeon Félix operated successfully upon Louis XIV’s fistula; the King was so pleased that he gave Félix fifteen thousand louis d’or, a country estate, and a patent of nobility. This elevation raised the social status of surgeons in France. In 1699 surgery was decreed to be a liberal art, and its exponents began to assume a high rank in French society. Voltaire called surgery “the most useful of all the arts,” and “the one in which the French excelled all other nations in the world.” 84
English surgery, however, had at least two credits in this age: in 1662 J. D. Major made the first successful intravenous injection in man, and in 1665–67 Richard Lower succeeded in transfusing blood from one animal into the veins of another; Pepys noted this latter event in his diary. 85 From that private gossip sheet we gather that operations were usually performed with only feeble anesthetics or none: when Pepys was operated on for stone in his bladder he received no chloroform and no antiseptics, but only “a soothing draught.” 86
Satires of the physician continued as in every generation. People resented his fees, his pompous dress in gown, wig, and conical hat, his grandiloquent speech, and his sometimes mortal mistakes. Boyle said that many people feared the doctor more than the disease. 87 Molière’s caricatures of the great profession were for the most part the good-natured fun of a man who nevertheless took care to keep on amiable terms with his physician. After all darts had been thrown it remained that the seventeenth century had seen a creditable advance in medical science through a hundred discoveries in anatomy, physiology, and chemistry, that the international exchange of medical knowledge was increasing, that notable teachers were sending out able pupils to all parts of Western Europe, that surgery was improving its methods and status, that specialists were developing greater knowledge and skill, and that more measures were being taken to promote public health. Municipal governments legislated sanitation. In 1656, when plague appeared in Rome, Monsignor Gastaldi, papal commissioner of health, made mandatory the cleansing of streets and sewers, the regular inspection of aqueducts, the provision of public facilities for the disinfection of clothing, and the requirement of health certificates from all persons entering the city. 88 As wealth rose, men built sturdier houses that could keep rats at a respectful distance and so reduce the spread of plague. Better supplies of water—the first necessity of civilization—enabled the willing body to be clean. For more and more people it was becoming physically possible to be civilized.
XI. RESULTS
All in all, the seventeenth century was one of the peak periods in the history of science. See it in its arching gamut, from Bacon calling men to labor for the advancement of learning, and Descartes marrying algebra to geometry; through the improvement of telescopes, microscopes, barometers, thermometers, air pumps and mathematics; through Kepler’s planetary laws, Galileo’s swelling firmament, Harvey’s charting of the blood, Guericke’s obstinate hemispheres, Boyle’s skeptical chemistry, Huygens’ multifarious physics, Hooke’s polymorphous tentatives, and Halley’s cosmetary predictions, culminating in Leibniz’ notational calculus and Newton’s cosmic synthesis: what previous century had equaled that performance? The modern mind, said Alfred North Whitehead, has “been living upon the accumulated capital of ideas provided for it by the genius of the seventeenth century” in science, literature, and philosophy. 89
The influence of science spread in widening arcs. It affected industry by supplying the physics and chemistry for new ventures in technology. In education it compelled a lessening of emphasis on the humanities—on literature, history, and philosophy; for the development of industry, commerce, and navigation demanded practical knowledge and minds. Literature itself felt the new influence: the scientist’s pursuit of order, precision, and clarity suggested similar virtues in poetry and prose, and accorded well with the classic style exemplified by Molière, Boileau, and Racine, by Addison, Swift, and Pope. The Royal Society, according to its historian, required of its members “a close, naked, natural way of speaking, . . . bringing all things as near to mathematical plainness as they can.” 90
The triumphs of mathematics and physics, giving period to comets and laws to stars, affected philosophy and religion. Descartes and Spinoza accepted geometry as the ideal of philosophy and exposition. There seemed no need, henceforth, to posit in the universe anything but matter and motion. Descartes saw all the world, except the human and divine mind, as a machine; Hobbes challenged the exception, and formulated a materialism in which even religion would be a tool of the state for manipulating human machines. The new physics, chemistry, and astronomy seemed to show a universe operating according to invariable laws; this cosmos allowed no miracles, therefore answered no prayers, therefore needed no God. Perhaps He could be kept to give the world machine an inaugural push; but thereafter he might retire to be an Epicurean-Lucretian deity, mindless of the world and men. Halley was said to have assured a friend of Berkeley that “the doctrines of Christianity” were now “inconceivable.” 91 Boyle, however, saw in the revelations of science additional evidence of the existence of God. “The world,” he wrote, “behaves as if there were diffused throughout the universe an intelligent being”; and in a sentence recalling Pascal he added, “The soul of man [is] a nobler and more valuable being than the whole corporeal world.” 92 Dying, Boyle left a fund to finance lectures that would demonstrate the truth of Christianity against “notorious infidels, viz., atheists, theists, pagans, Jews, and Mohammedans,” to which he added a proviso that the lectures must not mention the controversies among Christians. 93
Many scientists agreed with Boyle, and many believing Christians joined in praising science. “In these last hundred years,” said Dryden at the close of the century, “almost a new Nature has been revealed to us—more errors . . . have been detected, more useful experiments have been made, more noble secrets in optics, medicine, anatomy, and astronomy have been discovered, than in all these doting and credulous ages from Aristotle to us.” 94 This was a wild but significant exaggeration, revealing the conviction of the “moderns” that they had won the battle of the books with the “ancients.” In any case men could not but see that the sciences were increasing human knowledge while religions quarreled and statesmen warred. Science now rose to a new status of honor among human enterprises; indeed, by the end of this epoch it was already being hailed as the harbinger of Utopia and the savior of mankind. “The application of science to nature,” said Fontenelle in 1702, “will constantly grow in scope and intensity, and we shall go on from one marvel to another. The day will come when man will be able to fly by fitting on wings to keep him in the air; the art will increase, . . . till one day we sha
ll be able to fly to the moon.” 95 Everything was progressing except man.
CHAPTER XIX
Isaac Newton
1642–1727
I. THE MATHEMATICIAN
HE WAS born in a small farm at Woolsthorpe, in the county of Lincoln, on December 25, 1642 (Old Style)—the year in which Galileo died; cultural, like economic, leadership was passing from the south to the north. At birth he was so small that (his mother later told him) he might have been put into a quart mug, and so weak that no one thought he would live beyond a few days. 1 As his father had died some months earlier, the boy was brought up by his mother and an uncle.
At twelve he was sent to the public school at Grantham. He did not do well there; he was reported as “idle” and “inattentive,” neglecting prescribed studies for subjects that appealed to him, and giving much time to mechanical contrivances like sundials, water wheels, and homemade clocks. After two years at Grantham he was taken from school to help his mother on the farm, but again he skimped his duties to read books and do mathematical problems. Another uncle, recognizing his ability, sent him back to school, and arranged for Newton’s admission to Trinity College, Cambridge (1661), as a subsizar—a student who earned his expenses by various services. He took his degree four years later, and was soon thereafter elected a fellow of the college. He dealt chiefly with mathematics, optics, astronomy, and astrology; in this last study he maintained interest till late in his life.
In 1669 his mathematics teacher, Isaac Barrow, resigned; and on Barrow’s recommendation of him as an “unparalleled genius,” Newton was appointed to succeed him; he held this chair at Trinity for thirty-four years. He was not a successful teacher. “So few went to hear him,” his secretary recalled, “and fewer that understood him, that ofttimes he did in a manner, for want of hearers, read to the walls.” 2 On some occasions he had no auditors at all, and returned sadly to his room. There he built a laboratory—the only one then to be found in Cambridge. He made many experiments, mainly in alchemy, “the transmuting of metals being his chief design”; 3 but also he was interested in the “elixir of life” and the “philosopher’s stone.” 4 He continued his alchemist studies from 1661 to 1692, and even while writing the Principia; 5 he left unpublished manuscripts on alchemy totaling 100,000 words or more, “wholly devoid of value.” 6 Boyle and other members of the Royal Society were feverishly engaged in the same quest for manufacturing gold. Newton’s aim was not clearly commercial; he never showed any eagerness for material gains; probably he was seeking some law or process by which the elements could be interpreted as transmutable variations of one basic substance. We cannot be sure that he was wrong.
Outside his rooms at Cambridge he had a small garden; there he took short walks, soon interrupted by some idea which he hurried to his desk to record. He sat little, but rather walked about his room so much that (said his secretary) “you might have thought him . . . among the Aristotelian sect” of Peripatetics. 7 He ate sparingly, often skipped a meal, forgot that he had missed it, and grudged the time he had to give to eating and sleeping. “He rarely went to dine in the hall; and then, if he had not been [re]minded, would go very carelessly, with shoes down at the heels, stockings untied . . . and his head scarcely combed.” 8 Many stories were told, and many were invented, about his absent-mindedness. On awakening from sleep, we are assured, he might sit on his bed for hours undressed, engrossed in thought. 9 When he had visitors he would sometimes disappear into another room, jot down ideas, and quite forget his company. 10
During those thirty-five years at Cambridge he was a monk of science. He drew up “rules of philosophizing”—i.e., of scientific method and research. He rejected the rules which Descartes in his Discours had set up as a priori principles from which all major truths were to be derived by deduction. When Newton said, “Non fingo hypotheses”—I do not invent hypotheses 11—he meant that he offered no theories as to anything beyond observation of phenomena; so he would hazard no guess as to the nature of gravitation, but would only describe its behavior and formulate its laws. He did not pretend to avoid hypotheses as cues to experiments; on the contrary, his laboratory was devoted to testing a thousand ideas and possibilities, and his record was littered with hypotheses tried and rejected. Nor did he repudiate deduction; he merely insisted that it should start from facts and lead to principles. His method was to conceive possible solutions of a problem, work out their mathematical implications, and test these by computation and experiment. “The whole burden of [natural] philosophy,” he wrote, “seems to consist in this—from the phenomena of motions to investigate the forces of nature, and then from these forces to demonstrate the other phenomena.” 12 He was a compound of mathematics and imagination, and no one can understand him who does not possess both.
Nevertheless we proceed. His fame has two foci—calculus and gravitation. He began his work on the calculus in 1665 by finding the tangent and radius of curvature at any point on a curve. He called his method not calculus but “fluxions,” and gave for this term an explanation upon which we cannot improve:
Lines are described, and thereby generated, not by the apposition of parts, but by the continued motion of points; superficies [planes] by the motion of lines; solids by the motion of superficies; angles by the rotation of the sides; portions of time by continual flux; and so in other quantities . . . Therefore, considering that quantities, which increase in equal times, and by increasing are generated, became greater or less according to the greater or less velocity with which they increase or are generated, I sought a method of determining quantities from the velocities of the motions or increments with which they are generated; and calling these velocities of the motions or increments Fluxions, and the generated quantities Fluents, I fell by degrees upon the Method of Fluxions . . . in the years 1665 and 1666. 13
Newton described his method in a letter to Barrow in 1669, and referred to it in a letter to John Collins in 1672. He probably used the method in reaching some of the results in his Principia (1687), but his exposition there (probably for the convenience of his readers) followed accepted geometrical formulas. He contributed a statement of his fluxions procedure—but not over his own name—to Wallis’ Algebra in 1693. Not till 1704, in an appendix to his Opticks, did he publish the account just quoted. It was characteristic of Newton to delay publication of his theories; perhaps he wished first to resolve the difficulties suggested by them. So he waited till 1676 to announce his binomial theorem,* though he had probably formulated it in 1665.
These deferments embroiled the mathematicians of Europe in a disgraceful controversy that for a generation disrupted the international of science. For between Newton’s communication of his “fluxions” to his friends in 1669 and the publishing of the new method in 1704, Leibniz developed a rival system at Mainz and Paris. In 1671 he sent to the Académie des Sciences a paper containing the germ of the differential calculus. 14 On a visit to London, January to March, 1673, Leibniz met Oldenburg; he had already corresponded with him and Boyle; Newton’s friends later believed—historians now doubt 15—that Leibniz on this trip received some suggestion of Newton’s fluxions. In June, 1676, at the request of Oldenburg and Collins, Newton wrote a letter for transmission to Leibniz, explaining his method of analysis. In August Leibniz replied to Oldenburg, including some examples of his own work in calculus; and in June, 1677, in a further letter to Oldenburg, he described his form of differential calculus, and his system of notation, which differed from Newton’s. In the Acta Eruditorum for October, 1684, he again expounded the differential calculus, and in 1686 he published his system of integral calculus. In the first edition of the Principia (1687) Newton apparently accepted Leibniz’s independent discovery of calculus:
In letters which went between me and that most excellent geometer, G. W. Leibniz, ten years ago, when I signified that I was in the knowledge of a method of determining maxima and minima, of drawing tangents, and the like, . . . that most distinguished man wrote back that he had also fallen
upon a method of the same kind, and communicated his method, which hardly differed from mine except . . . in his forms of words and symbols. 16
This gentlemanly acknowledgment should have contracepted controversy. But in 1699 a Swiss mathematician, in a communication to the Royal Society, suggested that Leibniz had borrowed his calculus from Newton. In 1705 Leibniz, in an anonymous review of Newton’s Opticks, implied that Newton’s fluxions were an adaptation of the Leibnizian calculus. In 1712 the Royal Society appointed a committee to examine the documents involved. Before the year was out the Society published a report, Commercium Epistolicum, asserting the priority of Newton, but leaving open the question of Leibniz’ originality. In a letter of April 9, 1716, to an Italian priest in London, Leibniz protested that Newton’s scholium had settled the question. Leibniz died November 14, 1716. Soon afterward Newton denied that the scholium “allowed him [Leibniz] the invention of the calculus differentialis independently of my own.” In the third edition of the Principia (1726) the scholium was omitted. 17 The dispute was hardly worthy of philosophers, since either claimant might have bowed to Fermat’s priority.
II. THE PHYSICIST
Mathematics, however wonderful, was only a tool for calculating quantities; it did not profess to understand or describe reality. When Newton turned from the tool to the ultimate quest, he addressed himself first to the mystery of light. His first lectures at Cambridge were on light, color, and vision; characteristically he did not publish his Opticks till thirty-five years later, 1704. He had no itch to print.