Isaac Newton

Based on Wikipedia: Isaac Newton

In 1665, a twenty-two-year-old Cambridge student fled a plague-ravaged university and retreated to his family's farmhouse in rural Lincolnshire. Over the next two years, working alone with nothing but his notebooks and a prism, he would invent calculus, discover the laws of motion and gravitation, and revolutionize our understanding of light and color. No scientist before or since has accomplished so much in so short a time.

His name was Isaac Newton.

An Unlikely Beginning

Newton entered the world on Christmas Day, 1642, so premature and frail that his mother reportedly said he could have fit inside a quart mug. His father, also named Isaac, had died three months earlier. When young Isaac was three, his mother remarried and left him behind with his grandmother to go live with her new husband, a reverend named Barnabas Smith.

Newton never forgave her.

Years later, as a teenager compiling a list of his sins, he wrote: "Threatening my father and mother Smith to burn them and the house over them." This was not metaphorical teenage angst. Newton meant it literally. The abandonment left psychological scars that shaped his notoriously prickly personality for the rest of his life.

His mother eventually returned when her second husband died, and she tried to make Isaac into a farmer. He hated it. Fortunately, his uncle and schoolmaster recognized something extraordinary in the boy and convinced his mother to send him back to school. The motivation that drove Newton to become the top student in his class? Revenge. He wanted to humiliate a schoolyard bully who had beaten him in a fight. Newton won a second confrontation, and then decided the best revenge was academic superiority.

He distinguished himself by building sundials and working models of windmills—early hints of the mechanical genius to come.

The Miracle Years

At Cambridge, Newton was unremarkable. He started as a "subsizar," a student who paid his way by working as a servant to wealthier students—emptying chamber pots, running errands, waiting tables. The curriculum was still based on Aristotle's ancient texts, though Newton also read modern philosophers like René Descartes and astronomers like Galileo.

Then came the plague.

The Great Plague of 1665 killed roughly a quarter of London's population. Cambridge closed its doors, and students scattered. Newton retreated to Woolsthorpe Manor, his family's farmhouse. What happened next defies explanation.

In two years of solitary work, Newton developed the foundations of calculus—a mathematical framework for understanding change and motion that remains essential to physics, engineering, and economics today. He formulated his theory of universal gravitation, the insight that the same force pulling an apple to the ground also holds the moon in orbit around Earth and the planets around the sun. He conducted experiments with prisms that revealed white light to be a mixture of all colors, overturning centuries of belief about the nature of light itself.

The physicist Louis Trenchard More later observed that "there are no other examples of achievement in the history of science to compare with that of Newton during those two golden years." This is not hyperbole. A young man in his early twenties, working entirely alone in a farmhouse, with no collaborators, no internet, no scientific journals, essentially invented modern physics and modern mathematics simultaneously.

How Gravity Changed Everything

Before Newton, humanity had two different explanations for motion. Things on Earth fell down because they sought their "natural place" at the center of the universe—Aristotle's view. Meanwhile, planets moved in circles because the heavens operated by completely different rules—celestial physics was fundamentally separate from terrestrial physics.

Newton's revolutionary insight was that these were the same phenomenon.

The force pulling an apple toward the ground is identical to the force keeping the moon in orbit. The moon is essentially falling toward Earth continuously, but its sideways motion carries it forward fast enough that it keeps missing. An orbit is just a perpetual fall that never lands.

This single idea—universal gravitation—unified heaven and Earth under one mathematical framework. For the first time, humans could use equations to predict where a planet would be centuries from now, or where a cannonball would land, or why tides rose and fell. Newton's laws explained the elliptical orbits that Johannes Kepler had discovered decades earlier but couldn't explain. They predicted that comets would return on predictable schedules. They even showed that Earth couldn't be a perfect sphere—it must bulge slightly at the equator due to its rotation.

When French expeditions later confirmed that Earth was indeed an oblate spheroid, exactly as Newton predicted, European scientists largely abandoned all competing theories. Newtonian mechanics became the operating system of the universe.

Newton published these ideas in 1687 in a book with the Latin title Philosophiæ Naturalis Principia Mathematica—Mathematical Principles of Natural Philosophy. Scholars call it simply the Principia, and many consider it the most important scientific book ever written. It established classical mechanics, the physics that would dominate for over two centuries until Einstein's theory of relativity modified our understanding at very high speeds and very strong gravitational fields.

Even today, Newton's laws remain remarkably accurate for everyday physics. NASA uses them to plot spacecraft trajectories. Engineers use them to design bridges and buildings. They only break down at extreme conditions—near black holes, or at speeds approaching light—conditions far removed from ordinary human experience.

The Nature of Light

Newton's work on optics was equally revolutionary. Before him, most natural philosophers believed white light was pure and simple, while colors were somehow corrupted or modified versions of white light. Newton demonstrated the opposite.

Using a prism—a triangular piece of glass—he separated a beam of sunlight into a rainbow of colors. Then, with a second prism, he recombined those colors back into white light. His conclusion was startling: white light isn't fundamental at all. It's a mixture of all the colors of the visible spectrum. Red, orange, yellow, green, blue, violet—these are the truly fundamental components, and white is their combination.

Newton built the first reflecting telescope, using a curved mirror instead of a lens to gather light. This design avoided the color distortion that plagued earlier telescopes. Variations of his design remain in use today, including the Hubble Space Telescope.

His book Opticks, published in 1704, collected this work. It also included his speculations about whether light might consist of particles—a question that would take another two centuries to resolve. (The answer, bizarrely, is both yes and no: light exhibits properties of both waves and particles, a duality that Newton anticipated but couldn't fully articulate.)

The Invention of Calculus

How do you describe something that is constantly changing? Before calculus, this question had no good answer.

Consider a falling apple. At any given instant, it has a certain speed. But that speed is constantly increasing as gravity accelerates it. How fast is it going at the exact moment it has fallen for precisely one second? Not during the second, not after the second—at that infinitesimal point in time?

The ancient Greeks had struggled with such questions. Zeno's paradoxes—like the one about Achilles never catching the tortoise—exposed deep problems with reasoning about infinite divisions of space and time. Mathematicians had developed workarounds for specific problems, but no general framework existed.

Newton created one. He called his method "fluxions," imagining quantities flowing through time like water in a stream. The rate of that flow—what we now call a derivative—captured instantaneous change. The accumulated flow over time—what we now call an integral—captured total change. Newton developed these ideas starting in 1664, and by May 1665, he could compute the tangent line and curvature at any point of any continuous curve.

This was, to use a technical term, unprecedented.

A German polymath named Gottfried Wilhelm Leibniz independently developed his own version of calculus about a decade later. A bitter priority dispute erupted between Newton's supporters and Leibniz's supporters, each side accusing the other of plagiarism. Today, historians credit both men: Newton developed calculus first, but Leibniz published first and invented a much more elegant notation—the "dx" and "∫" symbols still used in every calculus textbook today.

Ironically, Newton's notation lost. Continental European mathematicians adopted Leibniz's symbols, while British mathematicians stubbornly clung to Newton's more cumbersome system out of national pride. British mathematics fell behind for over a century as a result, only catching up after 1820 when they finally abandoned Newton's notation.

The Worst Professor at Cambridge

Despite his towering intellect, Newton was a terrible teacher.

He was appointed Lucasian Professor of Mathematics at Cambridge in 1669, at just twenty-six years old—a prestigious position that came with teaching obligations. Newton fulfilled those obligations in the most minimal way possible. His assistant Humphrey Newton (no relation) recorded that the professor would arrive at his scheduled lecture time, and if no students had shown up—which was almost always the case—he would reduce his planned thirty-minute lecture to fifteen minutes, deliver it to the empty walls, and then retreat to his experiments.

Over his entire career, Newton was assigned only three students to tutor. None of them accomplished anything noteworthy.

He simply wasn't interested in teaching. He was interested in discovering secrets of the universe, and students were an unwelcome distraction.

The Hidden Newton

Newton spent at least as much time on alchemy and biblical chronology as he did on physics and mathematics. These pursuits remained almost entirely secret during his lifetime, and for centuries afterward historians downplayed them as embarrassing eccentricities.

But to Newton, they were all part of the same quest: understanding God's creation. Alchemy wasn't just a misguided attempt to turn lead into gold—it was a search for the hidden principles underlying matter itself. Biblical chronology wasn't mere superstition—it was an attempt to construct an accurate timeline of human history from the most authoritative source available.

Newton was deeply religious, but his beliefs were unorthodox. He privately rejected the doctrine of the Trinity—the idea that God exists as three persons (Father, Son, and Holy Spirit) in one being. This was heresy, and if discovered, could have ended his career. He never took holy orders as a priest, which was normally required of Cambridge fellows, managing to obtain a special exemption from King Charles II.

His religious views remained hidden until long after his death. When his private papers were finally examined in the twentieth century, scholars were astonished to discover that this titan of rational science had written more about theology and alchemy than about physics and mathematics combined.

The Later Years

In 1696, Newton left Cambridge for London, accepting a position as Warden of the Royal Mint. It was intended as a sinecure—a comfortable government job with a salary and few actual duties. Newton, characteristically, took it seriously.

He pursued counterfeiters with obsessive zeal, personally interrogating suspects and gathering evidence. England was in the midst of a currency crisis; the existing silver coins had been clipped and debased over the years, their edges shaved off by people collecting the silver. Newton oversaw the "Great Recoinage," replacing all the old coins with new ones that had milled edges (those ridges you see on quarters today) to prevent clipping.

Three years later, he was promoted to Master of the Mint, the top position, which he held until his death. He was knighted by Queen Anne in 1705—not for his scientific achievements, but essentially as a political favor related to a parliamentary election.

Newton also served as president of the Royal Society, Britain's premier scientific organization, from 1703 until his death in 1727. He used this position ruthlessly, squashing rivals and controlling scientific discourse. His dispute with Leibniz over calculus became personally vicious, with Newton using his institutional power to have the Royal Society officially rule in his own favor.

He never married and apparently never had a romantic relationship. He was prickly, vindictive, and capable of holding grudges for decades. He suffered at least two nervous breakdowns. He was, by most accounts, an extraordinarily difficult person.

He was also, by any reasonable measure, the most influential scientist in human history.

The Shape of Modern Science

Before Newton, "natural philosophy" was largely a matter of argument and speculation. After Newton, it became mathematical physics. You didn't just propose ideas about how the universe worked—you expressed them in equations that could make precise, testable predictions.

This shift created modern science.

The Principia demonstrated that a few simple mathematical laws could explain an astonishing range of phenomena: the fall of an apple, the orbit of the moon, the paths of comets, the shape of the Earth, the timing of tides. If such diverse phenomena could all follow from the same principles, what else might be unified under mathematical law?

Over the following centuries, scientists found that electricity and magnetism were aspects of the same force, that heat was molecular motion, that light was an electromagnetic wave, that atoms were built from subatomic particles obeying quantum rules. Each unification followed Newton's template: find the mathematical law, derive the consequences, test the predictions.

Newton gave science its method, its ambition, and its first great triumph. The Enlightenment that followed—with its faith in reason, its belief in progress, its confidence that the universe was comprehensible—drew directly on his achievement.

When Newton died in 1727 at age eighty-four, he was given a state funeral and buried in Westminster Abbey. The poet Alexander Pope composed his epitaph:

Nature and nature's laws lay hid in night;
God said "Let Newton be" and all was light.

It's a poetic exaggeration, of course. But only slightly.