Isaac Newton (20 page)

I have explained the phenomena of the heavens and of our sea by the force of gravity, but I have not yet assigned a cause to gravity.… I have not as yet been able to deduce … the reasons for these properties of gravity, 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.…
³²

So gravity was not mechanical, not occult, not a hypothesis. He had proved it by mathematics. “It is enough,” he said, “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.”
³³
It could not be denied, even if its essence could not be understood.

He had declared at the outset that his mission was to discover the forces of nature. He deduced forces from celestial bodies’ motion, as observed and recorded. He made a great claim—the System of the World—and yet declared his program incomplete. In fact, incompleteness was its greatest virtue. He bequeathed to science, that institution in its throes of birth, a research program, practical and open-ended. There was work to do, predictions to be computed and then verified.

“If only we could derive the other phenomena of nature from mechanical principles by the same kind of reasoning!” he wrote. “For many things lead me to have a suspicion that all phenomena may depend on certain forces by which the particles of bodies, by causes not yet known, either are impelled toward one another and cohere in regular figures, or are repelled from one another and recede.”
³⁴
Unknown
forces—as mysterious still as the forces he sought through his decades-long investigation of alchemy. His suspicion foresaw the program of modern physics: certain forces, attraction and repulsion, final causes not yet known.

13
 
Is He Like Other Men?

A
S THE CENTURY BEGAN
Bacon had said, “The mechanic, mathematician, physician, alchemist, and magician all immerse themselves in Nature, with a view to works, but all so far with feeble effort and slight success.”
¹
He sought to prepare the stage for a new type, so far unnamed, who would interpret and penetrate nature and teach us how to command it. The prototype for
scientist
was not quite ready.

Halley heralded the
Principia
in 1687 with the announcement that its author had “at length been prevailed upon to appear in Publick.”
²
Indeed, Newton, in his forty-fifth year, became a public man. Willy-nilly he began to develop into the eighteenth-century icon of later legend. Halley also wrote an introductory ode (“on This Splendid Ornament of Our Time and Our Nation, the Mathematico-Physical Treatise”). He sent a copy to the King—“If ever Book was so worthy of a Prince, this, wherein so many and so great discoveries concerning the constitution of the Visible World are made out, and put past dispute, must needs be grateful to your Majesty”
³
—and for easier reading included a summary of the explanation of tides; James II had
been Lord High Admiral before succeeding his brother on the throne.

“The sole Principle,” Halley explained, “is no other than that of
Gravity
, whereby in the Earth all Bodies have a tendency toward its Center.” The sun, moon, and planets all have such gravitation. The force decreases as the square of the distance increases. So a ton weight, if raised to a height of 4,000 miles, would weigh only a quarter-ton. The acceleration of falling bodies decreases in the same way. At great distances, both weight and fall become very small, but not zero. The sun’s gravity is prodigious, even at the immense distance of Saturn. Thus the author with great sagacity discovers the hitherto unknown laws of the motion of comets and of the ebbing and flowing of the sea.

Truth being uniform, and always the same, it is admirable to observe how easily we are enabled to make out very abstruse and difficult matters, when once true and genuine Principles are obtained.
⁴

Halley need not have bothered. James had other concerns. In his short, doomed reign, he was doing all he could to turn England toward Roman Catholicism, working his will on the army, the courts, the borough corporations and county governments, the Privy Council, and—not least—the universities. In Cambridge he made an antagonist of Newton.

The King asserted his authority over this bastion of Protestantism by issuing royal mandates, placing Catholics as fellows and college officers. Tensions rose—the abhorrence of popery was written into Cambridge’s statutes as well as its culture. The inevitable collision came in February
1687, when James ordered the university to install a Benedictine monk as a Master of Arts, with an exemption from the required examinations and oaths to the Anglican Church. University officials stalled and simmered. The professor of mathematics entered the fray—the resolute Puritan, theological obsessive, enemy of idolatry and licentiousness. He studied the texts: Queen Elizabeth’s charter for the university, the Act of Incorporation, the statutes, the letters patent. He urged Cambridge to uphold the law and defy the King: “Those that Councell’d his Majesty to disoblige the University cannot be his true friends.… Be courragious therefore & steady to the Laws.… If one P[apist] be a Master you may have a hundred.… An honest Courage in these matters will secure all, having Law on our sides.”
⁵
Before the confrontation ended, Cambridge’s vice-chancellor had been convicted of disobedience and stripped of his office, but the Benedictine did not get his degree.

Newton chose a path both risky and shrewd. Cambridge’s crisis was the nation’s crisis in microcosm. In England’s troubled soul Protestantism represented law and freedom; popery meant despotism and slavery. James’s determination to Catholicize the realm led to the downfall of the House of Stuart. Within two years a Dutch fleet had invaded a divided England, James had fled to France, and a new Parliament had convened at Westminster—among its members, Isaac Newton, elected by the university senate to represent Cambridge. As the Parliament proclaimed William and Mary the new monarchs in 1689, it also proclaimed the monarchy limited and bound by the law of the land. It abolished the standing army in peacetime and established a Declaration of
Rights. It extended religious toleration—except, explicitly, to Roman Catholics and to those special heretics who denied the doctrine of the Blessed Trinity. For all this Newton was present but silent. He reported back to Cambridge an argument with numbered propositions:

1. Fidelity & Allegiance sworn to the King, is only such a Fidelity & Obedience as is due to him by the law of the Land. For were that Faith and Allegiance more then what the law requires, we should swear ourselves slaves & the King absolute: whereas by the Law we are Free men.…
⁶

At the nation’s hub of political power, he rented a room near the House of Commons. He put on his academic gown, combed his white hair down around his shoulders, and had his likeness painted by the most fashionable portraitist in London.
⁷
Word of the
Principia
was spreading in the coffee-houses and abroad. He attended Royal Society meetings and social evenings. He met, and found a kind of amity with, Christiaan Huygens, now in London, and Samuel Pepys, the Royal Society’s president, as well as a young Swiss mathematician and mystic, Nicolas Fatio de Duillier, and John Locke, the philosopher in most perfect harmony with the political revolution under way. Huygens still had reservations about the
Principia
’s resort to mysterious attraction, but none about its mathematical rigor, and he promoted it generously. Huygens’s friend Fatio converted with loud enthusiasm to Newtonianism from Cartesianism. Fatio began serving as an information conduit between Newton and Huygens and took on the task of compiling errata for a revised edition of the
Principia
. Newton
felt real affection for this brash and hero-worshiping young man, who lodged with him increasingly in London and visited him in Cambridge.

Locke had just completed a great work of his own,
An Essay Concerning Human Understanding
, and saw the
Principia
as an exemplar of methodical knowledge. He did not pretend to follow the mathematics. They discussed theology—Locke amazed at the depth of Newton’s biblical knowledge—and these paragons of rationality found themselves kindred spirits in the dangerous area of anti-Trinitarianism. Newton began to send Locke treatises on “corruptions of Scripture,” addressing them stealthily to a nameless “Friend.” These letters ran many thousands of words. You seemed curious, Newton wrote, about the truth of the text of 1 John 5:7: “the testimony of the three in heaven.” This was the keystone, the reference to
the Father, the Word, and the Holy Ghost
. Newton had traced the passage through all ages: interpretation of the Latins, words inserted by St. Jerome, abuses of the Roman church, attributions by the Africans to the Vandals, variations in the margins. He said he placed his trust in Locke’s prudence and calmness of temper. “There cannot be a better service done to the truth then to purge it of things spurious,”
⁸
he said—but he nonetheless forbade Locke to publish this dangerous nonconformist scholarship.

In disputable places I love to take up with what I can best understand. Tis the temper of the hot and superstitious part of mankind in matters of religion ever to be fond of mysteries, & for that reason to like best what they understand least.

Meanwhile Pepys, who found his own mysteries in London’s clubs and gaming tables, came to Newton for advice on a matter of recreational philosophy: “the Doctrine of determining between the true proportions of the Hazards incident to this or that given Chance or Lot.” He was throwing dice for money and needed a mathematician’s guidance. He asked:

A—has 6 dice in a Box, with which he is to fling a 6.

B—has in another Box 12 Dice, with which he is to fling 2 Sixes.

C—has in another Box 18 Dice, with which he is to fling 3 Sixes.

   Q. whether B & C have not as easy a Taske as A, at even luck?
⁹

Newton explained why A has the best odds and gave Pepys the exact expectations, on a wager of £1,000, in pounds, shillings, and pence.

All these men maneuvered via friendly royal connections to seek a decorous and lucrative appointment for Newton in the capital. He pretended to demur—“the confinement to the London air & a formal way of life is what I am not fond of”
¹⁰
—but these plans tempted him.

London had flourished in the quarter-century since the plague and the fire. Thousands of homes rose with walls of brick, Christopher Wren designed a new St. Paul’s Cathedral, streets were widened and straightened. The city rivaled Paris and Amsterdam as a center of trading networks and a world capital of finance. England’s trade and
manufacturing were more centralized at one urban focus than ever before or since. News-papers appeared from coffee-houses and printers in Fleet Street; some sold hundreds of copies. Merchants issued gazettes, and astrologers made almanacs. The flow of information seemed instantaneous compared to decades past. Daniel Defoe, recalling the plague year, wrote, “We had no such thing as printed newspapers in those days to spread rumours and reports of things,… so that things did not spread instantly over the whole nation, as they do now.”
¹¹
It was understood that knowledge meant power, even knowledge of numbers and stars. The esoteric arts of mathematics and astronomy acquired patrons greater than the Royal Society: the Navy and the Ordnance Office. Would-be virtuosi could follow periodicals that sprang into being in the eighties and nineties:
Weekly Memorials for the Ingenious
and
Miscellaneous Letters Giving an Account of the Works of the Learned
.
¹²

Of the
Principia
itself, fewer than a thousand copies had been printed. These were almost impossible to find on the Continent, but anonymous reviews appeared in three young journals in the spring and summer of 1688, and the book’s reputation spread.
¹³
When the Marquis de l’Hôpital wondered why no one knew what shape let an object pass through a fluid with the least resistance, the Scottish mathematician John Arbuthnot told him that this, too, was answered in Newton’s masterwork: “He cried out with admiration Good god what a fund of knowledge there is in that book?… Does he eat & drink & sleep? Is he like other men?”
¹⁴