Isaac Newton

“I do not know what I may appear to the world, but to myself I seem to have been only like a boy playing on the sea-shore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me.”  

Isaac Newton (1642 - 1727) was a natural philosopher, mathematician, alchemists, eschatological theologian, and likely one of the greatest geniuses who ever lived.

He was born on a prosperous farm in Woolsthorpe, England, and his mother had high hopes that he would take over the family farm one day. But he fell in love with chemistry as a teenager, and was persuaded to attend Trinity College by an uncle who recognized his genius. He remained there for the rest of his life.

Whereas most scientists are remembered, if at all, for a single great discovery, Newton is remembered for three. The first are his Laws of Thermodynamics, which state that (1) motion is constant unless an external force is applied, (2) force can be calculated by the relationship between mass and acceleration (In consequence of which, entropy tends to increase over time), and (3) every physical action has an equal and opposite reaction. These laws have been foundational to all subsequent physics.

Newton's second major achievement was the mathematical description of the Law of Gravitation, which states that all objects exert an attractive force on all other objects directly proportional to their mass, and inversely proportional to their distance. This theory both explained and subsumed Kepler's laws of planetary motion, which had revealed that the planets orbit the Sun in an ellipses rather than in circles, as previously believed. Interestingly, Newton's theory of Gravitation was descriptive only - it did not propose any underlying causal mechanism, and the nature of that mechanism is still a major object of physics research. It thus constituted a kind of "spooky action at a distance" for the 17th century, which had tended to assume that causal relationships could only be expressed through physical contact between objects. The precise nature of gravity remains mysterious.

Along the way to his theory of gravity, Newton invented a new kind of mathematics called the Calculus - a method for computing rates of change in acceleration over time. Incredibly, he invented this form of calculation as a means of reaching other goals - what for another researcher might have been the work of a lifetime was, for Newton, a stepping stone on the path to discovery. At about the same time the German mathematician and diplomat Gottfried Liebenz created a similar system, which allowed for the same kinds of calculations. For years British and German philosophers waged a bitter and unseemly dispute over which of the two national champions of science deserved priority. Newton had no itch to see his name in print - he had waited over a decade to publish, and came to regret that he had allowed the controversy to disturb the tranquility of his research. The Calculus remains a fundamental tool of mathematics, and an inestimable aid to physics research.

Newton also published important treatises on light, and discovered by means of refraction that the color white is a composite of all other colors. He was active in alchemical research, which has been mostly forgotten, and wrote voluminous commentaries and interpretations of the Book of Revelations. What are now considered eccentric or pseudoscientific activities were regarded by Newton, and most of his peers, as legitimate science, giving striking evidence for the plasticity of the concept itself. Modern chemistry had to await the discoveries of Lavasoir in the 1770s, and Christianity was then both more tolerant and more mainstream among the educated elite than it is today. (It was not until Darwin published Origin of the Species in 1859 that atheism began to displace Christianity in both popular and educated culture, and a new and literalist version of Christianity called fundamentalism began to gain credence among its shrinking number of adherents.)
 

Newton's scientific accomplishments remain substantially in tact today, and were even regarded as a kind of revealed and ultimate truth until Einstein demonstrated the effect of Gravitation on light in a famous 1919 experiment (according to Newton, light, having no mass, should not be affected by gravity.) Nevertheless the equations he provided remain accurate for almost all practical purposes on the scale of everyday life. The Calculus and the Laws of Thermodynamics remain essentially as he left them, almost three centuries after his death.

Further biographical information:
http://www.biography.com/people/isaac-newton-9422656
Stanford Encyclopedia of Philosophy: Newton
http://plato.stanford.edu/entries/newton/

Part of a series on the Enlightenment (II of XVII)
https://www.facebook.com/pages/Modern-Intellectual-History/986713261343222