Titans of History

Sir Isaac Newton is arguably the greatest scientist of all time. Along with such figures as Copernicus, Kepler and Galileo, he is one of the giants of the scientific revolution. His most influential work, Principia Mathematica, fundamentally altered the way in which scientists observed and explained the natural world.

Newton’s main legacy was the fusion of mathematics and natural science, but he was a polymath who made significant contributions to philosophy, astronomy, theology, history, alchemy and economics. Without Newton, our understanding of the world would be unimaginably different.

Newton was born on Christmas Day, 1642. From an early age he seems to have taken firmly against the company of others. He formed a few close friendships in his life, but his general tendency to vacillate between shunning other people and picking fights with them appears to have been a peculiar part of his genius. It allowed him to focus his mind entirely on the scientific puzzles of the day.

As an undergraduate at Trinity College, Cambridge, Newton paid little attention to the syllabus set for him, largely ignoring the study of Aristotle in favor of the bright new scientists of his own day. The works of men such as René Descartes, Robert Boyle and Thomas Hobbes gripped him, and as he made notes on his reading, he began to question the world around him in ever greater detail.

It was at the age of twenty-three that Newton’s intellectual star really began to burn bright. He called 1665–6 his annus mirabilis

—his wonder year. He focused on various mathematical problems concerning the orbits of the moon and planets, developing in the process the theorem of calculus—a powerful mathematical tool vital to modern physics and engineering. The name calculus was coined by the German scientist Gottfried Leibniz, who developed the theory independently; Newton called it the “science of fluxions.” In later life the two men argued bitterly over who could lay claim to the discovery. In any case, it is clear that even as a young man in the 1660s Newton was already a mathematical pioneer.

Leaving Cambridge to escape the plague in 1666, Newton started to study natural mechanics. In old age he claimed to have first understood that it was gravity that controlled the orbit of the moon when he sat in his orchard and watched an apple fall from a tree. Apocryphal or not, the story soon became part of Newtonian folklore; perhaps its most felicitous appearance is in Byron’s Don Juan, where Newton is recorded as “the sole mortal who could grapple, Since Adam, with a fall, or with an apple.”

Back in Cambridge, Newton was swiftly appointed Lucasian professor of mathematics. He was free to pursue his own course of studies, and as he worked he corresponded with other leading scientists and mathematicians, including Boyle, Robert Hooke and Edmond Halley. During the 1670s he spent much time on theology, exploiting his formidable knowledge of the Bible and developing original and radical views on the Holy Trinity. He also became interested in alchemy—the science of turning base metals into gold—and began to build up a huge library of books on the subject. But it was the appearance of the so-called Great Comet of 1680–1 that lay at the root of Newton’s finest work.

In 1684 Newton began work on the project that would eventually become his ground-breaking Principia Mathematica. It was a work that would change both his life and the entire face of science. At its core lie Newton’s three fundamental laws of motion:

• an object in a state of rest or moving in a straight line will continue in such a state unless it is acted upon by an external force;

• the acceleration of a moving object is proportionate to and in the same direction as the force acting on it;

• for every action there is an equal and opposite reaction.

From these relatively straightforward laws Newton produced an astonishingly comprehensive analysis of the operation of the natural world. He explained everything from the behavior of small bodies and particles to the orbits of comets, planets and the moon. He put mathematics at the heart of the physical explanation of the world, where it remains to this day.

Newton’s brilliance rapidly made him one of the most eminent scientists in Europe. But he felt unable to continue working in the strictly conventional religious environment at Cambridge and was relieved to be appointed to a key role at the Royal Mint, which gave him a secure financial position for life. In 1703 he became president of the Royal Society, London’s most prestigious scientific community, and in 1704 he published Opticks, which dealt with the behavior of light and the forces that attract and repel particles and bodies. The following year he was knighted by Queen Anne, the first scientist ever to receive such an honor.