Robert Hooke criticised some of Newton's ideas, Newton was so offended that he withdrew from public debate. Due to Newton's paranoia, the two men remained enemies until Hooke's death.
Newton's committment to science (or something) is best demonstrated in one particular optical experiment. Having the idea colour is infused by pressure on the eye, he jambed a darning needle around the side of his eye until he could poke at its backside, dispassionately noting "white, darke & coloured circles" so long as he kept stirring with "ye bodkin." <Christianson is not clear on what N concluded from this>
He once said, in a letter to Hooke dated 5 February 1676, "If I have seen further it is by standing on ye shoulders of Giants" though this apparent modesty was barbed; Hooke was a man of short stature.
Newton argued that light is composed of particles. Later physicists instead favored a wave explanation of light because of certain experimental findings. Today's quantum mechanics recognizes a "wave-particle duality" however photons bear very little semblance to Newton's corpuscles (eg corpuscles refracted by accelerating toward the denser medium).
In his Hypothesis of Light of 1675, Newton relied on the existence of the ether to transmit forces between particles. Newton was in contact with Henry More, the Cambridge Platonist who was born in Grantham, on alchemy, and now his interest in the subject revived. He replaced the ether with occult forces based on Hermetic ideas of attraction and repulsion between particles. John Maynard Keynes, who acquired many of Newton's writings on alchemy, stated that "Newton was not the first of the age of reason: he was the last of the magicians." Newton's interest in alchemy cannot be isolated from his contributions to science. Had he not believed in the occult idea of action at a distance, across a vacuum, he may not have developed his theory of gravity. (See also Isaac Newton's occult studies.)
In 1679, Newton returned to his work on gravitation and its effect on the orbits of planets, with reference to Kepler's laws of motion, and consulting with Hooke and Flamsteed on the subject. He published his results in De Motu Corporum (1684). This contained the beginnings of the laws of motion that would inform the Principia.
Philosophiae Naturalis Principia Mathematica (now known as the Principia) was published in 1687 with encouragement and financial help from Edmond Halley. In this work Newton stated the three universal laws of motion that were not to be improved upon for the next three hundred years. He used the Latin word gravitas (weight) for the force that would become known as gravity, and defined the law of universal gravitation. In the same work he presented the first analytical determination, based on Boyle's Law, of the speed of sound in air.
With the Principia, Newton became internationally recognised. He acquired a circle of admirers, including the Swiss-born mathematician Nicolas Fatio de Duillier, with whom he formed an intense relationship that lasted until 1693. The end of this friendship led Newton to a nervous breakdown.
In the 1690s Newton wrote a number of religious tracts dealing with the literal interpretation of the Bible. Henry More's belief in the infinity of the universe and rejection of Cartesian dualism may have influenced Newton's religious ideas. A manuscript he sent to John Locke in which he disputed the existence of the Trinity was never published. Later works - The Chronology of Ancient Kingdoms Amended (1728) and Observations Upon the Prophecies of Daniel and the Apocalypse of St. John (1733) - were published after his death. He also devoted a great deal of time to alchemy; this was at a time when there was no clear distinction between the science of chemistry and the pseudoscience of alchemy.
Newton was also a member of Parliament from 1689 to 1690 and in 1701, but his only recorded comments were to complain about a cold draft in the chamber and request that the window be closed.
Newton moved to London to take up the post of warden of the Royal Mint in 1696, a position that he had obtained through the patronage of Charles Montagu, 1st Earl of Halifax, then Chancellor of the Exchequer. He took charge of England's great recoining, somewhat treading on the toes of Master Lucas (and finagling Edmond Halley into deputy comptroller of the temporary Chester branch). Newton became master of the Mint upon Lucas' death in 1699. These appointments were intended as sinecures, but Newton took them seriously, exercising his power to reform the currency and punish clippers and counterfeiters. He retired from his Cambridge duties in 1701.
In 1701 Newton anonymously published a law of thermodynamics now known as "Newton's Law of Cooling" in the Philosophical Transactions of the Royal Society.
In 1703 Newton became President of the Royal Society and an associate of the French Académie des Sciences. In his position at the Royal Society, Newton made an enemy of John Flamsteed, the Astronomer Royal, by attempting to steal his catalogue of observations.
Newton was knighted by Queen Anne in 1705.
Newton never married, nor had any recorded children. He died in London and was buried in Westminster Abbey.
Alexander Pope wrote a famous poem about Sir Isaac Newton: "Nature and nature's laws lay hid in night; God said Let Newton be! and all was light."
Writings by Newton
Short Chronicle, The System of the World, Optical Lectures, Universal Arithmetic, The Chronology of Ancient Kingdoms, Amended and De mundi systemate were published posthumously in 1728.
- Method of Fluxions (1671)
- Opticks (1704)
- Arithmetica Universalis (1707)