The work of Isaac Newton in mathematics and natural philosophy unified the work of his predecessors such as Copernicus, Kepler, Galileo, and Descartes and was a supreme effort of rational thought. Einstein wrote 200 years after Newton's death: "The whole development of our ideas concerning natural phenomena may be conceived as an organic development of Newton’s thought".
Isaac Newton was born, prematurely, at Woolsthorpe Manor, Lincolnshire, on Christmas Day 1642, his father having died three months earlier. His mother remarried three years later and left the boy to be raised for five years by his grandmother. His early years were a period of great uncertainty since the year 1642 also saw the start of the English Civil War, which led to the execution of the King, Charles I, on 30 January 1649, followed by the Commonwealth period under Oliver Cromwell, and the eventual Restoration of Charles II in 1660.
One of the witnesses of the execution of the King was Bishop Ussher whose scholarly studies of biblical chronology had placed the creation at 4004 BC. It is hardly surprising then that Newton also interested himself in chronology and the possible date of the end of the world, which he eventually decided would not be before 2060. His works on these subjects however were not published during his lifetime.
At ten he went to the Grammar School in Grantham, where he lodged with an apothecary, which no doubt contributed to his lifelong interest in chemistry, which at that time was beginning to emerge from alchemy (Boyle's "Sceptical Chymist" was published in 1661), but unlike his other work this did not lead him to make advances in the subject. J. M. Keynes, when he studied Newton's writings on alchemy, came to the view that "Newton was not the first of the age of reason: He was the last of the magicians."
In 1661 he went to Trinity College, Cambridge as a sizar, acting as a servant to the wealthy students, and in 1664, was accepted as a scholar, but the plague reached Cambridge in the summer of 1665 and he was forced to return home, where he laid the mathematical basis for much of his work published later, including his "method of fluxions" which was a version of the differential and integral calculus, also developed independently by his contemporary Leibniz. Among much else he demonstrated the generalised binomial theorem, and methods for approximating the roots of functions.
His tutor Isaac Barrow was sufficiently impressed with his advances in mathematics to resign the Lucasian Professorship, founded by Henry Lucas in 1663, so that Newton could have the Chair (1669). An unusual condition of the appointment, laid down by Lucas, was that the professor should not be active in the church or take holy orders. This was fortunate since Newton, although at Trinity College, was a unitarian (however the formal Unitarian church in England was not founded until 1774).
His election to the Royal Society (1672) was secured not by his mathematics but by his construction of one of the first reflecting telescopes. The science of Optics remained an important strand of his work, eventually published in book form 1704. He developed a theory of colour, based on his own experimental observations, that a prism decomposes white light into the many colours that form the visible spectrum, and that they recombine to form white light.
The problem of what forces controlled the motions of the planets and gave rise to Kepler's three laws was a hot topic of the time. Edmond Halley was able to persuade Newton that he should publish his results on this subject. This led to the publication of his main work, the "Mathematical Principles of Natural Philosophy", usually known by the shortened version of its Latin title as the "Principia". Halley even financed the publication, and saw it through the press in July 1687.
Working from a clearly expounded scientific method based on reason and experiment, and simple assumptions, such as his three laws of motion, Newton developed basic mechanics, and applied these methods to the inverse square law of gravitational attraction to explain the motion of the planets and their moons, the precession of equinoxes, the action of the tides, and the motion of comets, as well as terrestrial ballistics. Newton's universe united heaven and earth within a single set of laws. The Principia became the intellectual foundation of the modern view of the world. New editions were published in his lifetime in 1713 and 1726.
A further disruption in his life came with the accession of James II in 1685, who as a Catholic tried to appoint officers to Cambridge University on the basis of their religion rather than their qualifications. Newton led the opposition to this corruption. The University elected Newton as one of their two members to the Convention Parliament in 1689, which declared that James had abdicated and offered the crown to William and Mary. This involvement in state affairs led to him being appointed Warden of the Mint in 1696 and Master of the Mint in 1699, supervising renewal of the coinage, and the prosecution of counterfeiters. He was elected President of the Royal Society 1703 and reelected each year until his death. He was knighted by Queen Anne in 1705.
Newton died in 1727, and despite his heretical religious views, having refused on his death-bed to receive the sacrament, was buried and prominently memorialised in Westminster Abbey as a national hero. In 1730 Alexander Pope, wrote the famous epitaph: "Nature, and Nature's laws, lay hid in night. God said, Let Newton be! and all was light." Newton's research in the many subjects that interested him, even the biblical exegesis, was all part of a single quest to bring coherence and rational sense to a world in chaos.
William Blake's 1795 image of Newton depicted as deploying compasses to measure the world, is the basis of the 1995 sculpture by Eduardo Paolozzi that can now be seen in the forecourt of the British Library.
* Note: The dates of birth and death given above are those of the Julian calendar which was in force in England at the time. The year of his death is also sometimes given as 1726 since New Year's Day was for some legal purposes reckoned to be 25 March. The Gregorian calendar was introduced in England only in 1752, although it had been adopted in most other European countries earlier. Newton's Gregorian dates would have been: (4 January 1643 - 31 March 1727).