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# The Life of Sir Isaac Newton by Kenneth Shouler, Ph.D.

Newton was born in Woolsthorpe, Lincolnshire. He attended Cambridge University, receiving his bachelor's degree in 1665. By 1669 he was Lucasian Professor of Mathematics. He was elected fellow of the distinguished Royal Society in 1671 and served as its president from 1703 to his death. In his later years he was involved more in political and governmental affairs rather than in scientific work. Over the course of his life he attained unparalleled scientific achievements. Less known were his sustained interests in ancient chronology, biblical study, theology, and alchemy.

## Discoveries and Publications

Newton's genius was manifest by his early twenties. From 1664 to 1667 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. His masterpiece, Philosophiae Naturalis Principia Mathematica (The Mathematical Principles of Natural Philosophy), appeared in 1687. Simply put, this work sets forth the mathematical laws of physics and “the system of the world.” Not unlike Spinoza's Ethics, Newton's masterpiece followed the model of Euclidean geometry. Starting from mathematical definitions and axioms, Newton deduced propositions. In Newton's view, the world system was comprised of material bodies (masses composed of hard particles) at rest or in motion and interacting according to three axioms or laws of motion:

• 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.

• 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 forced equals mass times the rate of change of velocity, i.e., acceleration. Thus, the familiar formula, F = MA.)

• 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 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.

To the Enlightenment, Newton was more than a great physicist and mathematician. He was a cultural hero. The poet Alexander Pope voiced the spirit of the age in writing:

Nature and Nature's laws lay hid in night:

God said, Let Newton be! And all was Light.

## Newton's Philosophical Standing

Newton's elucidation of the laws of motion was preceded by a “scholium” in which he 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.

This scholium was the subject of much critical evaluation, however. Newton had always insisted on adherence to experimental observation and induction for advancing scientific knowledge, and he rejected speculative metaphysics. But absolute time and space are not observable.

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#### THE EVERYTHING GUIDE TO UNDERSTANDING PHILOSOPHY

By Kenneth Shouler, Ph.D.

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