Isaac Newton: History’s Greatest Mad (Angry?) Scientist

There exist many striking portraits of Isaac Newton (by then, Sir Isaac Newton) because during his lifetime his work arrested the world’s attention. Knowing something of Newton’s life, especially his early years, one gazes on these portraits seeking signs of genius and what the Encyclopedia Britannica—to take one standard reference—unapologetically characterizes as “psychosis.”

I do not discern that in the portraits. Newton is a handsome man with bold features, the usual shoulder-length flowing locks, and, of course, his eyes—demanding, inquisitorial, and, yes, I think, angry, accusing. He had his reasons.

He was born on Christmas Day, 1642 (“New Style,” January 4, 1643), in Woolsthorpe, Lincolnshire, England, the only son of a yeoman who died before Isaac was born. The culminating figure of the Scientific Revolution (1543–1687) and an intellectual engine of the Age of Enlightenment was born in the year that Galileo Galilei died. He would live to complete Galileo’s work (and Copernicus’s) on the mathematical science of planetary motion.

An underweight baby, not expected to survive his first day, he died in his sleep at eighty-four. Isaac lost his father before he was born, and, within two years, he lost his mother, too, who remarried a wealthy minister who placed Isaac with his grandmother and carried off Isaac’s mother to start a new family. For nine years, Isaac was separated from his mother, until her new husband died. His “pronounced psychotic tendencies have been ascribed to this traumatic event.” He later counted in one of his regular inventories of his “sins” a threat to burn his mother and stepfather in their house. Whether or not Newton was psychotic, he lived his whole life with an acute sense of insecurity, including about his work, and flew into uncontrollable rages when questioned. These rages persisted throughout his brilliant, successful, and celebrated later life and made him a social isolate.

He attended a grammar school in Grantham to prepare for university. Like other boys inspired by ideas and inventions of the Scientific Revolution—by this time, well advanced—Newton’s hobby was exercising his mechanical aptitude and tinkering skill to build clocks, sundials, and other “toys.” As for his school’s curriculum, it taught him Latin, but scant arithmetic.

Newton benefited from coming onto the scene in the later years of the Scientific Revolution. Universities still were controlled by Aristotelian Scholastics, mostly clergy, who taught a Christianized Aristotelian science. But by the time Newton entered Cambridge University in 1661, at nineteen, Trinity College had become a redoubt of Cartesians. By then, landmark works of science existed, the earliest in astronomy, a field safely in the celestial sphere of Galileo, Nicolaus Copernicus, and Johannes Kepler. In philosophy, René Descartes led the field, formulating a conception of the natural world as an intricate, impersonal, inert machine. Newton would advance the ideas of all these men, crowning the achievements of the Scientific Revolution.

Arriving at universities, young men inspired by science and later by Enlightenment ideas found their institutions essentially oblivious to those ideas. Heavily fortified by Aristotelian Scholastics of the Catholic Church—Franciscans, Benedictines, Dominicans, and Jesuits—labeled by their detractors as “schoolmen”—the universities’ official doctrine of the universe and nature was qualitative, in terms of “the great chain of being”: levels of perfection, a mutable earth and immutable heaven, and categories of causality.

Newton began college with Aristotle. The curriculum did not include the “new philosophy,” but by now it was elsewhere—in books, in new “academies” popping up across Europe, in pubs and cafes with supper clubs, and in correspondence among those like Newton already excited by it. He soon discovered the natural philosophy of Descartes and other mechanical (as contrasted with Aristotelian teleological) philosophers, who viewed the world as composed of particles of matter in motion, whose motion resulted in all observed phenomena of nature.

Newton’s notebook, given to him for his scholastic exercises, began to fill up beginning about 1664—which would have been his junior year—with what Newton called “Certain Philosophical Questions.” Its subtitle was his slogan in Latin: “Plato is my friend, Aristotle is my friend, but my best friend is truth.” The notebook reveals Newton’s grasp of the new conception of nature that framed the Scientific Revolution. He had comprehended Descartes and another French philosopher, Pierre Gassendi, who had revived Greek atomism to explain nature. Newton already was leaning toward that view instead of Descartes’s, which rejected atoms. Another seventeenth-century natural philosopher, Robert Boyle, laid the foundation for Newton’s work in chemistry.

The “Oxford University Newton Project” characterizes Newton’s college years: “Newton’s intellectual activities as an undergraduate were almost entirely extra-curricular. His near-total disregard for the subjects he was ostensibly supposed to be studying—primarily the ethics and natural philosophy of Aristotle—led to his being regarded as a decidedly poor scholar until his genius was recognized by the mathematics professor Isaac Barrow, among the leading mathematicians of the day. But as [his] notebook proves, he was in fact far more in touch with current developments in international scholarship than most of his tutors and professors.”

A conundrum is that Newton at this time also studied Plato via the works of Henry More, the Cambridge Platonist, and encountered there an alternative intellectual world, the magical Hermetic tradition, which explained phenomena by reference to alchemy and magic. It now seems bizarre that these two traditions of natural philosophy continued to exist in tension and to influence Newton’s thought throughout his scientific career. Later, when the scientific world shook its head at his view of an entirely invisible, unknown force called “gravity,” Hermetics may well have nerved him to defend his hypothesis.

Elsewhere, Newton had launched his study of mathematics, beginning with La Géométrie of Descartes and other new views of modern analysis applying algebra to problems of geometry. After revisiting the classical geometry of ancient Greece, Newton pushed into new territory, discovering the binomial theorem and developing a calculus that gained analytical power by employing the infinitesimal in finding the slopes of curves and areas under curves. 

Newton graduated in April 1665, and his may well have been the most precocious and brilliant undergraduate career in history—and he remained entirely unknown. In that year, an astonishing interlude in his scientific career—perhaps in science itself—began entirely by chance. It cannot be called “luck,” because the interlude was brought about by the plague, which closed the university. For two years, Newton had to stay at home. It became a perfect time to digest the intense period of study, intellectual exploration, and new ideas that had been his college years.

Here is a typical summary of those two years of immense growth and achievement: “Newton laid the foundations of the calculus and extended an earlier insight into an essay, ‘Of Colors,’ which contains most of the ideas elaborated in his Opticks. . . . [He] examined the elements of circular motion and, applying his analysis to the moon and the planets, derived the inverse square relation that the radially directed force acting on a planet decreases with the square of its distance from the sun—which was later crucial to the law of universal gravitation. The world heard nothing of these discoveries.” 

As noted, in the course of this work he developed the infinitesimal calculus (a mathematical field concerned, for example, with measuring the exact slope at any point on a curve), a method he called “fluxions.” (It was Gottfried Wilhelm Leibniz, developing calculus simultaneously and entirely independently, who called it “calculus.”)

When Cambridge reopened in 1667, Trinity elected Newton to a fellowship. Within two years, he had completed De Analysi, a tract explicating his progress in mathematics. He did so to protect his claim to inventing the “Analysis by Infinite Series” and circulated it among a few people, which began to make his name. He spent two years revising it, retitling it “On Methods of Series and Fluxions” (the latter a term privately used by Newton for his calculus). He had become the leading mathematician in Europe; very few people yet knew it.

This work so impressed Isaac Barrow (who brought De Analysi to the attention of a London publisher, although the first edition was not published until 1711) that Barrow resigned the Lucasian chair and recommended that Newton succeed him. The position excused Newton from tutoring but required him to present annually a course of lectures on his work. For his first lectures, he chose his work on optics; then, for three years, lectured on his advancement of those ideas that were to become Book One of his Opticks. The subject had become central to the Scientific Revolution and, by Newton’s time, had accumulated a long history of discoveries and theories.

Newton’s complex work, advanced year after year and presented in his lectures, addressed, criticized, and, in some cases, replaced, all that had come before—in particular, with a core contribution on colors. Historians have found no evidence that the theory of colors, elaborated in his lectures at Cambridge, caught much attention, scientific or general. The same must be said for aspects of his work in mathematics and the future content of the Principia—also introduced by Newton from the lectern. Was this a consequence of the Aristotelian-Scholastic worldview, and, to a lesser extent, the Cartesian view, which remained official Cambridge doctrine? One argument for that conclusion might be that it was the new Royal Society of London, launched in 1660, that ultimately took Newton’s ideas to the world.

When the unknown young man became Lucasian professor, it is likely that the reaction at the Royal Society was “Who?” But, in 1671, Newton’s reflecting telescope came to the attention of Society members, who asked to see it. Their enthusiasm pleased Newton—as did his election to the Society. Things seemed at last to be moving.

The next year, Newton proffered a paper on light and colors. It seemed to be well received, although there were questions and rumblings. Not to be ignored was Robert Hooke, a remarkable scientist and inventor and a leader of the Royal Society. Fancying himself a master of optics, Hooke penned a condescending critique of this unknown upstart that would have annoyed most men.

Isaac Newton was not “most men.” He exploded into rage, with a savage desire to publicly attack and bring down Hooke. He apparently simply could not rationally accept criticism. The incident so galled him that, in less than a year, even as normal, well-intentioned discussion continued, he severed his ties with almost everyone and retreated into a reclusive life. It amounted to a nervous breakdown.

Some three years later, on a rumor that Hooke had accepted his theory of colors, Newton presented a second paper, which became in most respects Book Two of Opticks. As usual, the paper introduced heretofore unknown insights. More broadly, it began to suggest a general system of nature. Hooke struck again, seeming to claim that Newton had stolen the content from him. Newton boiled over. At almost the same time, he was conducting an exchange on his theory of colors with Jesuits in Belgium. Their arguments reportedly were not impressive, but they, too, contended that his experiments were mistaken.

For some two years, Newton managed to correspond on the issue, but, in 1678, in a final shriek of rage and a second nervous breakdown, he lapsed into silence. His mother died the following year, deepening his isolation. For some half-a-dozen years, he withdrew from the intellectual forum. When someone initiated a correspondence, Newton ended it as soon as possible. In this seclusion, Newton submerged himself in the Hermetic tradition of his years at Trinity. He copied by hand treatise after treatise in search of valid interpretations of arcane imagery. 

It might seem that Newton “went off the deep end,” but from the Hermetic tradition came a decisive change in his conception of nature. He had been a mechanical philosopher in virtually standard seventeenth-century terms (for example, in his theory that light is a stream of tiny corpuscles diverted from its course by other media). But the logic of this mechanical philosophy denied any conception, any possibility, of action at a distance. And yet, there was static electricity (perhaps explained by invisible ethereal mechanisms?), and there was his view of light that required a universal ether as the medium of mechanical action. 

In 1679, Newton jettisoned the theory of ether—an invisible, unmeasurable deus ex machina brought in to uphold the mechanical view of billiard ball striking billiard ball as the only explanation of cause and effect. Ultimately, the intellectual courage to cut loose from this view empowered Newton to propose that a “force,” invisible to us and not understood—a force he called “universal gravitation”—explained exactly the movements of all bodies, sublunar and celestial. Explained mathematically, motions of earth, the sun, and the planets confirmed the observations and theories of Newton’s famous predecessors like Galileo and Copernicus.

This attraction and repulsion he could not explain; he applied it first to terrestrial phenomena. But by 1679, he was inspired to consider another application. It was suggested by a letter from Hooke, striving to reignite correspondence with Newton. What about planetary motion? What about the diversion of straight-line motion into central attraction? The wounded Newton would not respond to Hooke. But he did work out some of the mathematical elements of planetary motion. Hooke corrected Newton; Newton corrected Hooke.

Unfortunately, this correspondence led Hooke to charge Newton with plagiarism. The charge is viewed, today, as definitely mistaken. Hooke’s was an intuitive conception, not a mathematical one. Newton had worked it out mathematically—indeed, had done so a decade earlier. And yet, Newton later conceded that Hooke had shaped his ideas—especially the concept of universal gravitation.