If Sir Isaac Newton had not been distinguished as a mathematician and a natural philosopher, he would have enjoyed a high reputation as a theologian.

Newton's proof of the law of refraction is based on an erroneous notion that light travels faster in glass than in air, the same error that Descartes had made. This error stems from the fact that both of them thought that light was corpuscular in nature.

The history of the apple is too absurd. Whether the apple fell or not, how can any one believe that such a discovery could in that way be accelerated or retarded? Undoubtedly, the occurrence was something of this sort. There comes to Newton a stupid, importunate man, who asks him how he hit upon his great discovery. When Newton had convinced himself what a noodle he had to do with, and wanted to get rid of the man, he told him that an apple fell on his nose; and this made the matter quite clear to the man, and he went away satisfied.

It was God who breathed life into matter and inspired its many textures and processes. ...Rather than turn away from what he could not explain, he plunged in more deeply. ...There were forces in nature that he would not be able to understand mechanically, in terms of colliding billiard balls or swirling vortices. They were vital, vegetable, sexual forces—invisible forces of spirit and attraction. Later, it had been Newton, more than any other philosopher, who effectively purged science of the need to resort to such mystical qualities. For now, he needed them.

Newton's version of gravity violates common sense. How can one thing tug at another across vast spans of space? ...Newton's formalism nonetheless provided an astonishingly accurate means of calculating the orbits of planets; it was too effective to deny.

The prejudice for Sir Isaac has been so great, that it has destroyed the intent of his undertaking, and his books have been a means of hindering that knowledge they were intended to promote. It is a notion every child imbibes almost with his mother's milk, that Sir Isaac Newton has carried philosophy to the highest pitch it is capable of being carried, and established a system of physics upon the solid basis of mathematical demonstration.

Newton said that he made his discoveries by 'intending' his mind on the subject; no doubt truly. But to equal his success one must have the mind which he 'intended.' Forty lesser men might have intended their minds till they cracked, without any like result. It would be idle either to affirm or to deny that the last half-century has produced men of science of the calibre of Newton. It is sufficient that it can show a few capacities of the first rank, competent not only to deal profitably with the inheritance bequeathed by their scientific forefathers, but to pass on to their successors physical truths of a higher order than any yet reached by the human race. And if they have succeeded as Newton succeeded, it is because they have sought truth as he sought it, with no other object than the finding it.

I esteem his [Newton's] understanding and subtlety highly, but I consider that they have been put to ill use in the greater part of this work, where the author studies things of little use or when he builds on the improbable principle of attraction.

I do not mind at all that [Newton] is not a Cartesian provided he does not offer us suppositions like that of attraction.

... Newton was harbouring a terrible secret. He believed that the central Christian doctrine of the Trinity was a diabolical fraud and that all of modern Christianity was tainted by its presence. Jesus Christ, the Son of God, was not equal in any sense to God the Father, although he was divine, and was worthy of being worshipped in his own right. Newton did not arrive at these beliefs as a result of pursuing some dilettantish hobby; nor were they the result of studies he pursued at the end of his life. Instead, they lay at the heart of a massive research programme on prophecy and that he carried out early in his career. This was at least as strenuous, and, in his eyes, at least as "rational" as his work on physics and mathematics.

The room being hung around with a collection of the portraits of remarkable men, among them were those of Bacon, Newton and Locke. Hamilton asked me who they were. I told him they were my trinity of the three greatest men the world had ever produced, naming them. He paused for some time: “the greatest man,” said he, “that ever lived, was Julius Caesar.” Mr. Adams was honest as a politician, as well as a man; Hamilton honest as a man, but, as a politician, believing in the necessity of either force or corruption to govern men.

As to the Christian religion, besides the strong evidence which we have for it, there is a balance in its favour from the number of great men who have been convinced of its truth after a serious consideration of the question. Grotius was an acute man, a lawyer, a man accustomed to examine evidence, and he was convinced. Grotius was not a recluse, but a man of the world, who certainly had no bias on the side of religion. Sir Isaac Newton set out an infidel, and came to be a very firm believer.

I can venture to affirm, without meaning to pluck a leaf from the never-fading laurels of our immortal Newton, that the whole of his theology, and part of his philosophy, may be found in the Vedas.

Do not all charms flyAt the mere touch of cold philosophy?There was an awful rainbow once in heaven:We knew her woof, her texture: she is givenIn the dull catalogue of common things.Philosophy will clip an Angel's wings,Conquer all mysteries by rule of line.Empty the haunted air, and gnomed mine—Unweave a rainbow, as it erewhile madeThe tender-person'd Lamia melt into a shade.

John Maddox, the editor of Nature... retired in 1995. In August of that year, Maddox wrote an editorial entitled "Is the Principia Publishable Now?" in which he questioned whether or not Newton would get his ideas published today, given the current practice of peer review. Maddox speculates on what a reviewer would have written on receiving the script... He toys with the idea that Huygens (a contemporary... and opponent of Newton's ideas) would have written caustically about the gravitation ideas of Newton—"by what means, pray, does the author fancy that this magic can be contrived over the great distance between the Sun and Jupiter and without the lapse of time?"

Newton was not the first of the age of reason. He was the last of the magicians, the last of the Babylonians and Sumerians, the last great mind that looked out on the visible and intellectual world with the same eyes as those who began to build our intellectual inheritance rather less than 10,000 years ago. [...] [H]e looked on the whole universe and all that is in it as a riddle, as a secret which could be read by applying pure thought to certain evidence, certain mystic clues which God had laid about the world to allow a sort of philosopher's treasure hunt to the esoteric brotherhood. He believed that these clues were to be found partly in the evidence of the heavens and in the constitution of elements[...], but also partly in certain papers and traditions handed down by the brethren in an unbroken chain back to the original cryptic revelation in Babylonia.

In vulgar modern terms Newton was profoundly neurotic of a not unfamiliar type, but... a most extreme example. His deepest instincts were occult, esoteric, semantic — with profound shrinking from the world, a paralyzing fear of exposing his thoughts, his beliefs, his discoveries, in all nakedness to the inspection and criticism of the world. ...Until the second phase of his life, he was a wrapt, consecrated solitary, pursuing his studies by intense introspection.

His peculiar gift was the power of holding continuously in his mind a purely mental problem until he had seen straight through it. I fancy his pre-eminence is due to his muscles of intuition being the strongest and most enduring with which a man has ever been gifted. ... I believe that Newton could hold a problem in his head for hours and days and weeks until it surrendered to him its secret. Then being a supreme mathematical technician he could dress it up, how you will, for the purposes of exposition, but it was his intuition that was pre-eminently extraordinary.

Newton had other postulates by which he could get the law of angular momentum, but Newtonian laws were wrong. There's no forces, it's all a lot of balony. The particles don't have orbits, and so on.

Newton's age has long since passed through the sieve of oblivion, the doubtful striving and suffering of his generation has vanished from our ken; the works of some few great thinkers and artists have remained, to delight and ennoble those who come after us. Newton's discoveries have passed into the stock of accepted knowledge.

Newton is known for humbly declaring that he had achieved his great breakthroughs by 'standing on the shoulders of giants.' Though this may be true in part, it is largely humbug. Newton was hardly humble, and it would be just as true to say that he achieved greatness by stamping on the shoulders of giants. When others, such as Robert Hooke and Gottfried Leibniz, made breakthroughs in fields he was also researching, Newton fought ferociously to deny them credit for their work.

There is a basic incompatibility between any organization and freedom of thought. Suppose Newton had founded a Church of Newtonian Physics and refused to show his formula to anyone who doubted the tenets of Newtonian Physics?

A student of the history of physical science will assign to Newton a further importance which the average man can hardly appreciate. ...the separation ...of positive scientific inquiries from questions of ultimate causation.

The history of mathematics and mechanics for a hundred years subsequent to Newton appears primarily as a period devoted to the assimilation of his work and the application of his laws to more varied types of phenomena. So far as objects were masses, moving in space and time under the impress of forces as he had defined them, their behaviour was now, as a result of his labours, fully explicable in terms of exact mathematics.

When Newton saw an apple fall, he foundIn that slight startle from his contemplation ... A mode of proving that the earth turn'd roundIn a most natural whirl, called 'gravitation'.

My quotations from Newton suggest the motive which induced him to take a stand against the use of hypotheses, namely, the danger of becoming involved in disagreeable controversies. ...Newton could no more dispense with hypotheses in his own cogitations than an eagle can dispense with flight. Nor did Newton succeed in avoiding controversy.

Opticks was out of harmony with the ideas of 19th-century physics. ...an exposition of the "wrong" (i.e., corpuscular) theory of light,—even though it also contained many of the basic principles of the "correct" (i.e., wave) theory. Not only had Newton erred in his choice... but also he apparently had found no insuperable difficulty in simultaneously embracing features of two opposing theories. ...by adopting a combination of the two theories at once, he had violated one of the major canons of 19th-century physics... Today our point of view is influenced by the theory of photons and matter waves, or the... complementarity of Neils Bohr; and we may read with a new interest Newtons ideas on the interaction of light and matter or his explanation of the corpuscular and undulatory aspects of light.

Of the many references to Newton in 18th-century electrical writings only a small number were to the Principia, the greater part by far were to the Opticks. This was true not alone of the electrical writings but also in other fields of experimental enquiry. ...[The Opticks] would allow the reader to roam, with great Newton as his guide, through the major unresolved problems of science and even the relation of the whole world of nature to Him who had created it. ...in the Opticks Newton did not adopt the motto... —Hypotheses non fingo; I frame no hypotheses—but, so to speak, let himself go, allowing his imagination full reign and by far exceeding the bounds of experimental evidence.

In the year [1666] he retired again from Cambridge to his mother in & whilst he was musing in a garden it came into his thought that the power of gravity (which made an apple fall from the tree to the ground) was not limited to a certain distance from the earth, but must extend much farther than was usually thought — Why not as high as the Moon said he to himself, & if so that must influence her motion & perhaps retain her in her orbit. Whereupon he fell a calculating what would be the effect of that supposition being absent from the books & taking the common estimate in use among Geographers & our seamen before Norwood had measured the earth, that to 60 Engish miles were contained in one degree of . His computation did not agree with his Theory and inclined him then to entertain a notion that together with the power of gravity there might be a mixture of that force which the moon would have if it was carried along a vortex, but when the Tract of Picard of the measure of the earth came out shewing that a degree was about 69 1/2 English miles, he began his calculation anew & found it perfectly in agreement to his Theory.

[Newton] bought a book of Iudicial Astrology out of a curiosity to see what there was in that science & read in it till he came to a figure of the heavens which he could not understand for want of being acquainted with Trigonometry, & to understand the ground of that bought an English Euclid with an Index of all the problems at the end of it & only turned to two or three which he thought necessary for his purpose & read nothing but the titles of them finding them so easy & self evident that he wondered any body would be at the pains of writing a demonstration of them & laid Euclid aside as a trifling book, & was soon convinced of the vanity & emptiness of the pretended science of Iudicial astrology.

[Newton] achieved the clearest appreciation of the relation between the empirical elements in a scientific system and the hypothetical elements derived from a philosophy of nature.

Galileo first studied the motion of terrestrial objects, pendulums, free-falling balls, and projectiles. He summarized what he observed in the mathematical language of proportions. And he extrapolated from his experimental data to a great idealization now called the “inertia principle,” which tells us, among other things, that an object projected along an infinite, frictionless plane will continue forever at a constant velocity. His observations were the beginnings of the science of motion we now call “mechanics.”... Newton also invented a mathematical language (the "Fluxions" method, closely related to our present-day ) to express his mechanics, but in an odd historical twist, rarely applied that language himself.

But to return to the Newtonian Philosophy: Tho' its Truth is supported by Mathematicks, yet its Physical Discoveries may be communicated without. The great Mr. Locke was the first who became a Newtonian Philosopher without the help of Geometry; for having asked Mr. Huygens, whether all the mathematical Propositions in Sir Isaac's Principia were true, and being told he might depend upon their Certainty; he took them for granted, and carefully examined the Reasonings and Corollaries drawn from them, became Master of all the Physics, and was fully convinc'd of the great Discoveries contained in that Book.

Multiple-prism arrays were first introduced by Newton (1704) in his book Opticks. In that visionary volume Newton reported on arrays of nearly isosceles prisms in additive and compensating configurations to control the propagation path and the dispersion of light. Further, he also illustrated slight beam expansion in a single isosceles prism.

Newton was at heart a Cartesian, using pure thought as Descartes intended, and using it to demolish the Cartesian dogma of vortices.

In accordance with Newton's system, physical reality is characterised by concepts of space, time, the material point and force (interaction between material points). Physical events are to be thought of as movements according to law of material points in space. The material point is the only representative of reality in so far as it is subject to change. The concept of the material point is obviously due to observable bodies; one conceived of the material point on the analogy of movable bodies by omitting characteristics of extension, form, spatial locality, and all their 'inner' qualities, retaining only inertia, translation, and the additional concept of force.

In order to put his system into mathematical form at all, Newton had to devise the concept of differential quotients and propound the laws of motion in the form of total differential equations—perhaps the greatest advance in thought that a single individual was ever privileged to make.

Isaac Newton’s Philosophae Naturalis Principia Mathematica abstracted time from events, establishing its tractability to scientific calculation. Conceived as pure, absolute duration, without qualities, it conforms perfectly to its mathematical idealization (as the real number line). Since time is already pure, its reality indistinguishable from its formalization, a pure mathematics of change – the calculus – can be applied to physical reality without obstruction. The calculus can exactly describe things as they occur in themselves, without straying, even infinitesimally, from the rigorous dictates of formal intelligence. In this way natural philosophy becomes modern science.

Newton was the greatest genius that ever existed, and the most fortunate, for we cannot find more than once a system of the world to establish.

When Sir A. Fountaine was at Berlin with Leibnitz in 1701, and at supper with the Queen of Prussia, she asked Leibnitz his opinion of Sir Isaac Newton. Leibnitz said that taking mathematicians from the beginning of the world to the time when Sir Isaac lived, what he had done was much the better half; and added that he had consulted all the learned in Europe upon some difficult points without having any satisfaction, and that when he applied to Sir Isaac, he wrote him in answer by the first post, to do so and so, and then he would find it.

The weight of a smallish apple is, pleasingly, about 1 newton, or 1 N. ...Newton probably weighed about 700 newtons.

The view of space that exists independent of any relationship is called the absolute view. It was Newton's view, but it has been definitely repudiated by the experiments that have verified Einstein's theory of general relativity. ...There are unfortunately not a few good professional physicists who still think about the world as if space and time had an absolute meaning.

Despite Newton's belated appreciation of Euclid's geometry, he set it aside as an undergraduate and immediately turned to Descartes' Geometrie, a much more difficult text. Newton read a few pages... and immediately got stuck. ...The second time through, he progressed a page or two further before running into more difficulties. Again, he read it from the beginning, this time getting further still. He continued this process until he mastered Descartes' text. Had Newton mastered Euclid first, Descartes' analytic geometry would have been much easier to understand. Newton later advised others not to make the same mistake.But Descartes had ignited Newton's interest in mathematics, an interest that bordered on obsession.

After dinner, the weather being warm, we went into the garden, & drank tea under the shade of some apple trees; only he & myself. Amidst other discourse, he told me, he was just in the same situation, as when formerly, the notion of gravitation came into his mind. "Why should that apple always descend perpendicularly to the ground," thought he to him self; occasion'd by the fall of an apple, as he sat in a contemplative mood. "Why should it not go sideways, or upwards? but constantly to the earths centre? Assuredly, the reason is, that the earth draws it. There must be a drawing power in matter. The sum of the drawing power in the matter must be in the earth's center, not in any side of the earth. Therefore does this apple fall perpendicularly or toward the center. If matter thus draws matter; it must be in proportion to its quantity. Therefore the apple draws the earth, as well as the earth draws the apple."

By analyzing the measurements of , Johannes Kepler established that planetary motions weren't circles but ellipses... Through his telescopes, Galileo saw that the Sun had its perfection tarnished by ugly black spots. And the Moon wasn't a perfect sphere but looked like a place, complete with mountains and giant craters. So why didn't it fall down?Isaac Newton finally answered... by exploring... [a radical] idea... that heavenly objects obey the same laws as objects here on Earth. ...Newton ...realized that ...the fate of a horizontally fired cannon ball depends on its speed: it crashes to the ground only if its speed is below some magic value. ...[W]ith ever higher speeds, they'll travel farther ...before landing ...until ...they keep their height over the ground ...constant and never land, merely orbiting ...just like the Moon! Since he knew the strength of gravity near the Earth's surface... he was able to calculate the magic speed... 7.9 kilometers per second. Assuming the Moon... was obeying the same laws... he could similarly predict what speed it needed... Moreover, since the Moon took one month to travel around a circle whose circumference Aristarchos had figured out, Newton already knew its speed... Now he made a remarkable discovery: if he assumed that the force of gravity weakened like the inverse square... then this magical speed that would give the Moon a circular orbit exactly matched its measured speed! He had discovered the law of gravity... applying not merely here on Earth, but in the heavens as well. ...People boldly extrapolated not only to the macrocosmos... but also to the microcosmos, finding that many properties... could be explained by applying to... atoms... The scientific revolution had begun.

Newton did not show the cause of the apple falling, but he shewed a similitude between the apple and the stars. By doing so he turned old facts into new knowledge; and was well content if he could bring diverse phenomenon under "two or three Principles of Motion" even "though the Causes of these Principles were not yet discovered."

The mechanical philosophy is a case of being victimized by metaphor. I choose Descartes and Newton as excellent examples of metaphysicians of mechanism malgré eux, that is to say, as unconscious victims of the metaphor of the great machine. Together they have founded a church, more powerful than that founded by Peter and Paul, whose dogmas are now so entrenched that anyone who tries to reallocate the facts is guilty of more than heresy.

When he [Newton] uttered his Hypotheses non fingo he was saying in a very abbreviated, and hence cryptic way: In induction, I do not invent hypotheses, and in deduction I do not demonstrate from them. More fully, he meant that the inductive side of scientific method has a beginning, a middle, and an end and all must be complete before any deductive system is set up. The beginning consists in '"hinting several things" or making "conjectures" about the causes of phenomena...because they are "plausible consequences" drawn from the facts...they are not derived, like Descartes' conclusions, merely by the Light of Reason or intuition. Although hypothetical in character, Newton did not call them "hypotheses". The middle consists of examining these "hints" and improving them by observations and the tests of experiment. The end is defined by his remark: "and if no exception occur from phenomena, the conclusion may be pronounced generally" and considered "proved" as a "general law of nature". "Afterwards,", the deduction proceeds by assuming the conclusions established as principles, and from them demonstrating the phenomena...The peculiar character of this method, the stress upon experience and the rejection of hypotheses of the Cartesian kind, may be briefly described in Berkeley's words: "It is one thing to arrive at general laws of nature from a contemplation of of the phenomena, and another to frame an hypothesis, and from thence deduce the phenomena (S, 229).

The reader will recollect that we are here speaking of the Principia as a mechanical treatise only... As a work on dynamics, its merit is, that it contains a wonderful store of refined and beautiful mathematical artifices, applied to solve all the most general problems which the subject offered. It can hardly be said to contain any new inductive discovery respecting the principles of mechanics; for though Newton's "Axioms or Laws of Motion," which stand at the beginning of the book, are a much clearer and more general statement of the grounds of mechanics than had yet appeared, it can hardly be said that they contain any doctrines which had not been previously stated or taken for granted by other mathematicians.

Such, then, is the great Newtonian induction of universal gravitation, and such its history. It is indisputably and incomparably the greatest scientific discovery ever made, whether we look at the advance which it involved, the extent of the truth disclosed, or the fundamental and satisfactory nature of this truth.