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Sir Isaac Newton
(25 Dec 1642 - 20 Mar 1727)

English physicist and mathematician who made seminal discoveries in several areas of science, and was the leading scientist of his era.



And thus Nature will be very conformable to her self and very simple, performing all the great Motions of the heavenly Bodies by the Attraction of Gravity which intercedes those Bodies, and almost all the small ones of their Particles by some other attractive and repelling Powers which intercede the Particles. The Vis inertiae is a passive Principle by which Bodies persist in their Motion or Rest, receive Motion in proportion to the Force impressing it, and resist as much as they are resisted. By this Principle alone there never could have been any Motion in the World. Some other Principle was necessary for putting Bodies into Motion; and now they are in Motion, some other Principle is necessary for conserving the Motion.
— Sir Isaac Newton
From Opticks, (1704, 2nd ed. 1718), Book 3, Query 31, 372-3.
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Do not Bodies and Light act mutually upon one another; that is to say, Bodies upon Light in emitting, reflecting, refracting and inflecting it, and Light upon Bodies for heating them, and putting their parts into a vibrating motion wherein heat consists?
— Sir Isaac Newton
Opticks (1704), Book 3, Query 5, 133.
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Do not electric bodies by friction emit a subtile exhalation or spirit by which they perform their attractions?
— Sir Isaac Newton
As quoted in Roderick W. Home, Electricity and Experimental Physics in Eighteenth-Century Europe (1992), 103.
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Do not great Bodies conserve their heat the longest, their parts heating one another, and may not great dense and fix'd Bodies, when heated beyond a certain degree, emit Light so copiously, as by the Emission and Re-action of its Light, and the Reflexions and Refractions of its Rays within its Pores to grow still hotter, till it comes to a certain period of heat, such as is that of the Sun?
— Sir Isaac Newton
Opticks (1704), Book 3, Query II, 135.
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I use the word “attraction” here in a general sense for any endeavor whatever of bodies to approach one another, whether that endeavor occurs as a result of the action of the bodies either drawn toward one other or acting on one another by means of spirits emitted or whether it arises from the action of aether or of air or of any medium whatsoever—whether corporeal or incorporeal—in any way impelling toward one another the bodies floating therein. I use the word “impulse” in the same general sense, considering in this treatise not the species of forces and their physical qualities but their quantities and mathematical proportions, as I have explained in the definitions.
— Sir Isaac Newton
The Principia: Mathematical Principles of Natural Philosophy (1687), 3rd edition (1726), trans. I. Bernard Cohen and Anne Whitman (1999), Book I, Section II, Scholium, 588.
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If the Humours of the Eye by old Age decay, so as by shrinking to make the Cornea and Coat of the Crystalline Humour grow flatter than before, the Light will not be refracted enough, and for want of a sufficient Refraction will not converge to the bottom of the Eye but to some place beyond it, and by consequence paint in the bottom of the Eye a confused Picture, and according to the Indistinctuess of this Picture the Object will appear confused. This is the reason of the decay of sight in old Men, and shews why their Sight is mended by Spectacles. For those Convex glasses supply the defect of plumpness in the Eye, and by increasing the Refraction make the rays converge sooner, so as to convene distinctly at the bottom of the Eye if the Glass have a due degree of convexity. And the contrary happens in short-sighted Men whose Eyes are too plump. For the Refraction being now too great, the Rays converge and convene in the Eyes before they come at the bottom; and therefore the Picture made in the bottom and the Vision caused thereby will not be distinct, unless the Object be brought so near the Eye as that the place where the converging Rays convene may be removed to the bottom, or that the plumpness of the Eye be taken off and the Refractions diminished by a Concave-glass of a due degree of Concavity, or lastly that by Age the Eye grow flatter till it come to a due Figure: For short-sighted Men see remote Objects best in Old Age, and therefore they are accounted to have the most lasting Eyes.
— Sir Isaac Newton
Opticks (1704), Book 1, Part 1, Axiom VII, 10-11.
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Impressed force is the action exerted on a body to change its state either of resting or of moving uniformly straight forward.
— Sir Isaac Newton
The Principia: Mathematical Principles of Natural Philosophy (1687), 3rd edition (1726), trans. I. Bernard Cohen and Anne Whitman (1999), Definition 4, 405.
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It is inconceivable, that inanimate brute matter should, without the mediation of something else, which is not material, operate upon and affect other matter without mutual contact … That gravity should be innate, inherent, and essential to matter, so 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 to another, is to me so great an absurdity, that I believe no man who has in philosophical matters a competent faculty of thinking, can ever fall into it. Gravity must be caused by an agent, acting constantly according to certain laws; but whether this agent be material or immaterial, I have left to the consideration of my readers.
— Sir Isaac Newton
Third letter to Bentley, 25 Feb 1693. Quoted in The Works of Richard Bentley, D.D. (1838), Vol. 3, 212-3.
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Kepler’s laws, although not rigidly true, are sufficiently near to the truth to have led to the discovery of the law of attraction of the bodies of the solar system. The deviation from complete accuracy is due to the facts, that the planets are not of inappreciable mass, that, in consequence, they disturb each other's orbits about the Sun, and, by their action on the Sun itself, cause the periodic time of each to be shorter than if the Sun were a fixed body, in the subduplicate ratio of the mass of the Sun to the sum of the masses of the Sun and Planet; these errors are appreciable although very small, since the mass of the largest of the planets, Jupiter, is less than 1/1000th of the Sun's mass.
— Sir Isaac Newton
In Isaac Newton and Percival Frost (ed.) Newton’s Principia: Sections I, II, III (1863), 216.
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This Excellent Mathematician having given us, in the Transactions of February last, an account of the cause, which induced him to think upon Reflecting Telescopes, instead of Refracting ones, hath thereupon presented the curious world with an Essay of what may be performed by such Telescopes; by which it is found, that Telescopical Tubes may be considerably shortened without prejudice to their magnifiying effect.
On his invention of the catadioptrical telescope, as he communicated to the Royal Society.
— Sir Isaac Newton
'An Account of a New Catadioptrical Telescope Invented by Mr Newton', Philosophical Transactions (1672), 7, 4004.
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Thus far I have explained the phenomena of the heavens and of our sea by the force of gravity, but I have not yet assigned a cause to gravity. Indeed, this force arises from some cause that penetrates as far as the centers of the sun and planets without any diminution of its power to act, and that acts not in proportion to the quantity of the surfaces of the particles on which it acts (as mechanical causes are wont to do) but in proportion to the quantity of solid matter, and whose action is extended everywhere to immense distances, always decreasing as the squares of the distances.
— Sir Isaac Newton
The Principia: Mathematical Principles of Natural Philosophy (1687), 3rd edition (1726), trans. I. Bernard Cohen and Anne Whitman (1999), General Scholium, 943.
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To any action there is always an opposite and equal reaction; in other words, the actions of two bodies upon each other are always equal and always opposite in direction.
— Sir Isaac Newton
The Principia: Mathematical Principles of Natural Philosophy (1687), 3rd edition (1726), trans. I. Bernard Cohen and Anne Whitman (1999), Axioms, or Laws of Motion, Law 3, 417.
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To derive two or three general Principles of Motion from Phćnomena, and afterwards to tell us how the Properties and Actions of all corporeal Things follow from those manifest Principles, would be a very great step in Philosophy.
— Sir Isaac Newton
From 'Query 31', Opticks (1704, 2nd ed., 1718), 377.
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[1.] And first I suppose that there is diffused through all places an aethereal substance capable of contraction & dilatation, strongly elastick, & in a word, much like air in all respects, but far more subtile.
2. I suppose this aether pervades all gross bodies, but yet so as to stand rarer in their pores then in free spaces, & so much ye rarer as their pores are less ...
3. I suppose ye rarer aether within bodies & ye denser without them, not to be terminated in a mathematical superficies, but to grow gradually into one another.
— Sir Isaac Newton
Letter to Robert Boyle (28 Feb 1678/9). In H. W. Turnbull (ed.), The Correspondence of Isaac Newton, 1676-1687 (1960), Vol. 2, 289.
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See also:
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  • Isaac Newton - biography from Famous Men of Science (1889)
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  • Isaac Newton - “Playing on the Seashore” illustrated quote - Medium 500px.
  • Isaac Newton - “Playing on the Seashore” illustrated quote - Large 800px.
  • Isaac Newton - context of quote “A change in motion” - Medium image (500 x 250 px)
  • Isaac Newton - context of quote “A change in motion” - Large image (800 x 400 px)
  • Isaac Newton - context of quote “In experimental philosophy” - Medium image (500 x 250 px)
  • Isaac Newton - context of quote “In experimental philosophy” - Large image (800 x 400 px)
  • Isaac Newton - context of quote “Standing on the shoulders of giants” - Medium image (500 x 250 px)
  • Isaac Newton - context of quote “Standing on the shoulders of giants” - Large image (800 x 400 px)
  • Isaac Newton - context of quote “Impressed force is the action” - Medium image (500 x 250 px)
  • Isaac Newton - context of quote “Impressed force is the action” - Large image (800 x 400 px)
  • Isaac Newton - context of quote “Inherent force of matter is the power of resisting…” - Medium image (500 x 250 px)
  • Isaac Newton - context of quote “Inherent force of matter is the power of resisting…” - Large image (800 x 400 px)
  • Isaac Newton - context of quote “Plato is my friend” - Medium image (500 x 250 px)
  • Isaac Newton - context of quote “Plato is my friend” - Large image (800 x 400 px)
  • Isaac Newton - context of quote “Colours which appear through the Prism ” - Medium image (500 x 250 px)
  • Isaac Newton - context of quote “Colours which appear through the Prism ” - Large image (800 x 400 px)
  • Isaac Newton - context of quote “Nature does nothing in vain” - Medium image (500 x 250 px)
  • Isaac Newton - context of quote “Nature does nothing in vain” - Large image (800 x 400 px)
  • Isaac Newton - context of quote “No more causes of natural things should be admitted” - Medium image (500 x 250 px)
  • Isaac Newton - context of quote “No more causes of natural things should be admitted” - Large image (800 x 400 px)
  • Isaac Newton - context of quote “Truth is ever to be found in simplicity” - Medium image (500 x 250 px)
  • Isaac Newton - context of quote “Truth is ever to be found in simplicity” - Large image (800 x 400 px)
  • Isaac Newton - context of quote “Every body perseveres in its state of being at rest” - Medium image (500 x 250 px)
  • Isaac Newton - context of quote “Every body perseveres in its state of being at rest” - Large image (800 x 400 px)
  • Isaac Newton - context of quote “God, in the beginning, formed matter” - Medium image (500 x 250 px)
  • Isaac Newton - context of quote “God, in the beginning, formed matter” - Large image (800 x 400 px)
  • Isaac Newton - context of quote “The cause of gravity is what I do not pretend to know” - Medium image (500 x 250 px)
  • Isaac Newton - context of quote “The cause of gravity is what I do not pretend to know” - Large image (800 x 400 px)
  • Sir Isaac Newton’s Apple-Tree - debunking the myth, from Historic Ninepins: A Book of Curiosities by John Timbs (1869)
  • Newton and the Dog - debunking the myth about Newton’s dog Diamond.
  • Booklist for Isaac Newton.

Carl Sagan Thumbnail In science it often happens that scientists say, 'You know that's a really good argument; my position is mistaken,' and then they would actually change their minds and you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day. I cannot recall the last time something like that happened in politics or religion. (1987) -- Carl Sagan
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