# Isaac Newton:

The Metaphysicist

#### By Gabriel Blanchard

## Few scientists have illuminated the universe as Newton did—all but literally.

With the start of a new year, it feels fitting to take a look at a mind who, intellectually, started a new cosmos. Sir Isaac Newton revolutionized physics with his studies of motion, fluid dynamics, and light, and mathematics with the discovery of calculus.

Newton was born on Christmas day in 1642. Educated at Trinity College, Cambridge (a little ironically, given his private religious views), where he began to develop what would ultimately become calculus. The university closed in the summer of 1665—the last major outbreak of the Bubonic Plague in England took place that year. But by 1667, Cambridge had reopened and Newton had returned. Two years later he had become the Lucasian Professor of Mathematics, one of the most prestigious positions in Cambridge; three years after that, he was elected to the Royal Society.

Newton’s theory of gravity is probably his most celebrated. People knew before then, of course, that things fall down if you drop them, and also that the planets move in orbits; but it does not seem to have occurred to anyone to ask “Why do planets move in orbits?”, still less to connect that phenomenon with the bread landing buttered side down. In 1687, Newton published the *Principia Mathematica*, which set forth his famous laws of motion and his law of universal gravitation. Taken together, these provide a model of the solar system that accurately predicts the observed motion of everything in it. Although the work of twentieth century physicists like Albert Einstein and Niels Bohr revealed certain limitations in Newton’s work, the *Principia Mathematica* remains a seminal work of classical mechanics to this day.

Plato is my friend—Aristotle is my friend—yet my greatest friend is the truth.

His 1704 volume *Opticks* dramatically advanced the theory of light. By studying the refraction of white light through prisms, and successfully re-combining split colors of light into white light again, Newton correctly determined that color was an intrinsic property of light itself. He used this knowledge to invent the reflecting telescope, which solved the issue of color distortion that refracting telescopes like Galileo’s suffered from.

Sir Isaac Newton is somewhat less well-known for his studies in esoterica. Prophecy, astrology, and alchemy (especially the last) were among his keen interests. He emphatically distinguished such speculation from scientific observation; all the same, a tenth of his surviving corpus is devoted to alchemy. John Maynard Keynes, who bought some of Newton’s private papers at auction in the twentieth century, once called him “not the first of the scientists but the last of the magicians.”

As mentioned above, he had begun private work on the theory of calculus as early as 1666. Calculus is the mathematical study of certain kinds of change: things like finding the slope of a curve or the area of a region between two curves are calculus operations. German philosopher Gottfried Leibniz later claimed to have developed calculus himself, and was the first to publish his results, leading to a bitter feud between the two men. (Most modern scholars believe that both men independently arrived at the idea, though it bears saying that, of Leibniz’s virtues, strict honesty is not the most conspicuous.)

Newton died in late March of 1720; Voltaire, who was a personal friend, is thought to have attended his funeral. He was laid to rest in Westminster Abbey. The eminent poet Alexander Pope wrote of the great scientist’s work: “Nature and nature’s laws lay hid in night: / God said ‘Let Newton be’ and all was light.”

Page image obtained from Wikipedia under a CC BY-SA 3.0 license (source).

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