Sir Isaac Newton (1642-1727):
"Nature and Nature's Laws lay hid in night;
God said, 'Let Newton be!' -- And all was light." (Pope.)
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1. NEWTON'S LIFE:
South east of an area that was to become the English industrial heartland, in a little village called Woolsthorpe, Issaac Newton made his entry into the world. He was prematurely born, and, was so small at his birth, his mother used to say that "he might then have been put into a quart mug."1 His widowed mother - Newton's father had died several months before his birth - was to re-marry; and - there apparently being no room for a two year old in the new Newton household - this small misplaced child passed into the care of his grandmother.
Newton had a bad start with his schooling; he has been described as having been one of the poorest performing students in the grammar school in which his grandmother had placed him.2 The story is that the boy suffered from a blow delivered by a schoolyard bully; or was it that he was struck on the head by an apple: whatever it was, an event occurred whereby "the hard shell which imprisoned his genius was cracked wide open." The boy was to make a dramatic turn around, early in his scholastic career. He was to ask questions which many of us sooner or later have come to ask. What is light and how is it transmitted? What keeps the moon in the orbit of the earth, and the planets in the orbit of the sun? Why does the apple fall to the ground? Newton came, in time, to answer these questions and was to give positive proof of these answers, proofs and answers which serve us yet today.3
Somehow, interested people managed in 1661 to see that Newton entered Trinity College, Cambridge. By 1665 he was writing of "fluxions" and the law of gravitation. By 1667, Newton was made a fellow at Trinity, and soon thereafter, a professor of mathematics, a post which he held to at least 1696.
Newton, the scientist from Cambridge, was in direct competition with Hooke, the scientist from Oxford. It was likely this competition which drove Newton to write his Principia, it is said, within a period of eighteen months; a task which physically and mentally drained its author. It was to be Newton's great gift to mankind.
"Mathematically it [Principia] can only be compared to Euclid's Elements; in its physical insight and its effect on ideas only to Darwin's Origin of Species. It immediately became the bible of the new science ..."4
It is said that Edmund Halley (yes, the man who had a comet named after him) came from Oxford in 1684 (the other camp) with the view of consulting with Newton on a rather esoteric question concerning the centripetal forces of the universe. Newton had already solved the problem a couple of years back, -- and Halley, was much impressed. One might speculate that Halley put a bee in Newton's ear that his rival was hot on the trail and, of course, the first to publish is the winner. It was thought that the Royal Society would pay the printing and distribution costs of Newton's work, but at the last minute it reneged. (Hooke had taken over the secretary's position in 1677.) Halley, apparently a man of greater financial resources, came to Newton's aid; he supervised the printing of the work and paid the bills.
Newton's work had the effect of putting Cartesian philosophy on its ear. Those who subscribe to this philosophy accept certain truths, a priori (truths not derived from experience). I do not want to get into a philosophical discussion, at this place, about deductive reasoning, sufficient to say that accepting notions which have no basis in reality and then to proceed to build on those is not the approach used by those who hit upon the great scientific discoveries of the 17th century, or any scientific discovery, ever.
Newton specifically stated in his work that he was advancing beyond the philosophical to the mathematical. His statements were not based on assumptions or suppositions, but rather on mathematical proof set out in detail. Descartes had thought that all matter in space is contained within a thin fluid, which gave rise to vortexes, which in turn held all the celestial bodies in place. The theories advanced by Descartes are every bit as interesting as that advanced by Newton: the problem is that Descartes had absolutely no proof to back up his theories - Newton did.
Rene Descartes was a dualist: and the principal point I wish to make, is: Newton was not. It is important, even to the most rudimentary understanding of Newtonian theory, to understand that any law of nature is universal in its application. Newton had made a rather fundamental break with the past in stating that there is no difference between earthly and celestial phenomena. "Like effects in nature are produced by like causes." The ancient belief, the dualist belief, is that there are worlds apart from the earth and these be perfect worlds, whereas the earth is not.
In person, Newton was medium in height and in his later years was inclined to stoutness. He was extremely absent-minded particularly when in the midst of trying to fathom a theoretical problem; it is said that he would sometimes sit on the side of his bed half-dressed for hours at a time. He frequently would not know whether he had dined, or no. "He was a lifelong bachelor, he never wore glasses, and his teeth were sound and serviceable to the day of his death."5
As for his temper: He was "invidious, ambitious, exceedingly avid of praise, and very irritable when contradicted." It is further written of Newton that he had a suspicious and quarrelsome temper.6 An example of Newton's quarrelsome temper can be exemplified by the running argument he had with the supporters of his German counterpart, Leibniz.
Newton lived in London in a comfortable setting and had "a beautiful niece to keep house for him."7 He pursued his studies without any subsidies; and he bought all of his own equipment.8
Newton died on March 20th, 1727. He was buried in Westminster Abbey where most all of England's great are buried.9
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2. NEWTON'S ACCOMPLISHMENTS:-
Newton's accomplishments in life were many. Generally, he devoted much of his energy towards alchemy, theology, and history. In 1668, Newton built the first reflecting telescope. During his lifetime he was involved in the development of the calculus. It was Newton who struck upon the Laws of Motion and the Law of Gravitation. He sat in parliament, 1689-90. In 1696, he was appointed warden of the Mint; and then, in 1699, he was appointed the master of the Mint, a position which he held until his death. He sat again in parliament in 1701 for his university. In 1703, Newton was to become the president of the Royal Society, another post that he held at his death. In 1705, Newton was knighted by Queen Anne.
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3. NEWTON'S LAWS OF MOTION:-
As already mentioned, Newton's principal work was brought forth in 1687, Philosophiae Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy); it is the first and the greatest work ever written on theoretical physics. In this work, Newton showed how his principle of universal gravitation explained both the motions of heavenly bodies and the falling of bodies on earth. "Every body continues in its state of rest, or of uniform motion in a right line, unless it is compelled to change that state by forces impressed upon it. ... The change of motion is proportional to the motive force impressed; and is made in the direction of the right line in which that force is impressed. ... [and] To every action there is always opposed an equal reaction: or, the mutual actions of two bodies upon each other are always equal, and directed to contrary parts." And there you have it: Newton's Laws of Motion.
Thus, Newton determined that there did exist natural laws. One law was that there did exist an attractive force (gravity); it exists between any two particles of matter. He developed his explanation of this natural law as it relates to light between the years 1664 and 1666. This force described by Newton was thought to be of equal application throughout the universe, here on earth and, out there, among the cosmos; it came to be called "universal gravitation." It is this same force that will haul the ungriped coffee cup crashing to the floor, and keeps the celestial objects in their path.
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4. NEWTON'S LAW OF UNIVERSAL GRAVITATION:-
Newton struck upon his theory of gravitation at the age of 23. Like most perfectionists Newton was cautious in his pronouncements, such that, the publication of this theory was not to take place until many years later.10
Newton's Law of Universal Gravitation has been described as follows: It is a force between any two bodies and is "directly proportional to the product of their masses and inversely proportional to the square of the distance between them. ... The measure of the force of gravitation on a given body on earth is the weight of that body." While certain of Newton's theories have not stood the tests applied in the 20th century, his law of universal gravitation has stood: "In the general theory of relativity, gravitation is explained geometrically: matter in its immediate neighborhood causes the curvature of the four-dimensional space-time continuum."
Newton's scientific enquiries led to the development of a fundamental scientific tool -- differential calculus. But this was something he just did en route, just so much staging. Newton's fame rests and will forever rest on his formulations in regards to motion and attraction, as found in his work, Principia.
"The calculus, as developed by Newton, could be used and was used by him for the solving of a great variety of mechanical and hydrodynamic problems. It immediately became the mathematical instrument for all understanding of variables and motion, and hence of all mechanical engineering, and remained almost the exclusive one until well into the present century. In a very real sense it was as much an instrument of the new science as the telescope."11
Differential Calculus, or, as Newton called it, "Theory of Fluxions" was developed by Newton as early as 1666, but it was only published in 1704 as an appendix to Newton's book, Optics.12 Prior to these times, mathematicians and astronomers "used intricate geometrical constructions ..."13
There was controversy on the point as to who exactly was the first person to discover the system of differential and integral calculus. Some say it was Newton; others would say it was the German, Leibniz. "The verdict of science is that the methods were invented independently, and that although Newton was the first inventor, a greater debt is owning to Leibniz for the superior facility and completeness of his method."14 What Newton and Leibniz were to do, was to invent a tool, the calculus, in order to come up with proofs for these answers as were formulated in their impressive and active brains. With such a mathematical tool as the calculus, Newton was able to calculate the mass of each of the planets; sun and earth included. He estimated that the earth's density was between five and six times that of water (the figure by scientists today is 5.5). A number of very brilliant men, down through the generations, have looked at Newton's work and have shook their heads: his work was "above the reach of human reason and experience."15
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6. NEWTON'S LIGHT THEORY:-
Newton's Light Theory was published in 1704; his Opticks set forth the theory that light is composed of particles. "Light," according to Newton, "is composed of tiny particles, or corpuscles, emitted by luminous bodies." This particle theory dominated optics until the 19th century when it was replaced by the wave theory of light.16 Generally though, Newton's light theory was accepted until the 20th century, when experiments were carried out by Michelson and Einstein which led to the electromagnetic theory of light.
To conclude I quote from Professor Bernal's Science in History:
"Newton's theory of gravitation and his contribution to astronomy mark the final stage of the transformation of the Aristotelian world-picture begun by Copernicus. For a vision of spheres, operated by a first mover or by angels on God's order, Newton had effectively substituted that of a mechanism operating according to a simple natural law, requiring no continuous application of force, and only needing divine intervention to create it and set it in motion."17
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8. QUOTES:-
"Errors are not in the art but in the artificers.18
"O Diamond! Diamond! Thou little knowest the mischief done!" (Said to a pet dog who knocked over a candle and set fire to his papers.)
"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 seashore, 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."19
"If I have seen further (than you and Descartes) it is by standing upon the shoulders of Giants."20
"I have not yet been able to discover the cause of these properties of gravity from phenomena and I frame no hypotheses... It is enough that gravity does really exist and acts according to the laws I have explained, and that it abundantly serves to account for all the motions of celestial bodies.
That one body may act upon another at a distance through a vacuum without the mediation of anything else, by and through which their action and force may be conveyed from one another, is to me so great an absurdity that, I believe, no man who has in philosophic matters a competent faculty of thinking could ever fall into it."21
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9. NOTES:
1 C. R. L. Fletcher's Historical Portraits (Oxford: Clarendon Press, 1909-19), p. 29.
2 Dr. Marshall Dale's Medical Biographies (1952) (University of Oklahoma Press, 1987), p. 47.
3 These mathematical proofs were "probably not understood in his own day by more than a dozen people." See Hoyle's preface in his biography of Nicolaus Copernicus (London: Heinemann, 1973).
4 Bernal's Science in History (1954) (Cambridge, Mass.: MIT Press, 1981), p. 485.
5 Dale, op. cit., p. 52.
6 John Flamsteed (1646-1719), the first astronomer-royal of England, the man who set up the Greenwich Observatory, and who complied the first trustworthy catalogue of the fixed stars; as quoted by Dale, op. cit., p. 52.
7 Fletcher, op. cit., p. 33.
8 Dale, op. cit., p. 51.
9 Sir David Brewster wrote the standard biography on Newton, Memoirs of Newton (1855).
10 Bernal's Science in History, op. cit., p.482.
11 Bernal's Science in History op. cit., p. 484.
12 Fletcher, op. cit., p. 31.
13 See Hoyle's biography of Nicolaus Copernicus, op. cit., preface.
14 Chambers Biographical Dictionary.
15 See, for example, Adam Smith.
16 See James Clerk-Maxwell (1831-79)