Newton Sir Isaac (1642–1727), English physicist and mathematician, one of the greatest scientists of all time. Born in Woolsthorpe, Lincolnshire, he attended Cambridge University, receiving the B.A. in 1665; he became a fellow of Trinity in 1667 and Lucasian Professor of Mathematics in 1669. He was elected fellow of the Royal Society in 1671 and served as its president from 1703 until his death. In 1696 he was appointed warden of the mint. In his later years he was involved in political and governmental affairs rather than in active scientific work. A sensitive, secretive person, he was prone to irascibility – most notably in a dispute with Leibniz over priority of invention of the calculus. His unparalleled scientific accomplishments overshadow a deep and sustained interest in ancient chronology, biblical study, theology, and alchemy.
In his early twenties Newton’s genius asserted itself in an astonishing period of mathematical and experimental creativity. In the years 1664– 67, he discovered the binomial theorem; the ‘method of fluxions’ (calculus); the principle of the composition of light; and fundamentals of his theory of universal gravitation.
Newton’s masterpiece, Philosophiae Naturalis Principia Mathematica (‘The Mathematical Principles of Natural Philosophy’), appeared in 1687. This work sets forth the mathematical laws of physics and ‘the system of the world.’ Its exposition is modeled on Euclidean geometry: propositions are demonstrated mathematically from definitions and mathematical axioms. The world system consists of material bodies (masses composed of hard particles) at rest or in motion and interacting according to three axioms or laws of motion: (1) Every body continues in its state of rest or of uniform motion in a straight line unless it is compelled to change that state by forces impressed upon it. (2) The change of motion is proportional to the motive force impressed and is made in the direction of the straight line in which that force is impressed. [Here, the impressed force equals mass times the rate of change of velocity, i.e., acceleration. Hence the familiar formula, F % ma.] (3) To every action there is always opposed an equal reaction; or, the mutual action of two bodies upon each other is always equal and directed to contrary parts. Newton’s general law of gravitation (in modern restatement) is:
Every particle of matter attracts every other particle with a force varying directly as the product of their masses and inversely as the square of the distance between them. The statement of the laws of motion is preceded by an equally famous scholium in which Newton enunciates the ultimate conditions of his universal system: absolute time, space, place, and motion. He speaks of these as independently existing ‘quantities’ according to which true measurements of bodies and motions can be made as distinct from relative ‘sensible measures’ and apparent observations. Newton seems to have thought that his system of mathematical principles presupposed and is validated by the absolute framework. The scholium has been the subject of much critical discussion. The main problem concerns the justification of the absolute framework. Newton commends adherence to experimental observation and induction for advancing scientific knowledge, and he rejects speculative hypotheses. But absolute time and space are not observable. (In the scholium Newton did offer a renowned experiment using a rotating pail of water as evidence for distinguishing true and apparent motions and proof of absolute motion.) It has been remarked that conflicting strains of a rationalism (anticipating Kant) and empiricism (anticipating Hume) are present in Newton’s conception of science. Some of these issues are also evident in Newton’s Optics (1704, especially the fourth edition, 1730), which includes a series of suggestive ‘Queries’ on the nature of light, gravity, matter, scientific method, and God. The triumphant reception given to Newton’s Principia in England and on the Continent led to idealization of the man and his work. Thus Alexander Pope’s famous epitaph: Nature and Nature’s laws lay hid in night; God said, ‘Let Newton be!’ and all was light. The term ‘Newtonian’, then, denoted the view of nature as a universal system of mathematical reason and order divinely created and administered. The metaphor of a ‘universal machine’ was frequently applied. The view is central in the eighteenth-century Enlightenment, inspiring a religion of reason and the scientific study of society and the human mind. More narrowly, ‘Newtonian’ suggests a reduction of any subject matter to an ontology of individual particles and the laws and basic terms of mechanics: mass, length, and time. See also FIELD THEORY, PHILOSOPHY OF SCIENCE , QUANTUM MECHANICS , SPACE , TIM. H.S.T.