Quotes from The Principia: Mathematical Principles of Natural Philosophy

“This most beautiful system [The Universe] could only proceed from the dominion of an intelligent and powerful Being.”
― Isaac Newton, quote from The Principia: Mathematical Principles of Natural Philosophy

“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.”
― Isaac Newton, quote from The Principia: Mathematical Principles of Natural Philosophy

“Resistance is usually ascribed to bodies at rest, and impulse to those in motion; but motion and rest, as commonly conceived, are only relatively distinguished; nor are those bodies always truly at rest, which commonly are taken to be so.”
― Isaac Newton, quote from The Principia: Mathematical Principles of Natural Philosophy

“This most beautiful system of the sun, planets, and comets, could only proceed from the counsel and dominion of an intelligent and powerful Being. And if the fixed stars are the centers of other like systems, these, being formed by the like wise counsel, must be all subject to the dominion of One.”
― Isaac Newton, quote from The Principia: Mathematical Principles of Natural Philosophy

“the one as much as it advances that of the other. If a body impinge upon another, and by its force change the motion of the other, that body also (because of the equality of the mutual pressure) will undergo an equal change, in its own motion, towards the contrary part.”
― Isaac Newton, quote from The Principia: Mathematical Principles of Natural Philosophy

“Hypotheses non fingo (Latin for "I feign no hypotheses", "I frame no hypotheses", or "I contrive no hypotheses")”
― Isaac Newton, quote from The Principia: Mathematical Principles of Natural Philosophy

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“The reason that the rich were so rich, Vimes reasoned, was because they managed to spend less money.

Take boots, for example. He earned thirty-eight dollars a month plus allowances. A really good pair of leather boots cost fifty dollars. But an affordable pair of boots, which were sort of OK for a season or two and then leaked like hell when the cardboard gave out, cost about ten dollars. Those were the kind of boots Vimes always bought, and wore until the soles were so thin that he could tell where he was in Ankh-Morpork on a foggy night by the feel of the cobbles.

But the thing was that good boots lasted for years and years. A man who could afford fifty dollars had a pair of boots that'd still be keeping his feet dry in ten years' time, while the poor man who could only afford cheap boots would have spent a hundred dollars on boots in the same time and would still have wet feet.

This was the Captain Samuel Vimes 'Boots' theory of socioeconomic unfairness.”
― Terry Pratchett, quote from Men at Arms: The Play

“You are not a man as ordinary men are. They think they have a right to all beasts; to hunt them and eat them, or to subjugate them and rule their lives. You know you have no such right to mastery. The horse that carries you will do so because he wishes to, as does the wolf that hunts beside you. You have a deeper sense of yourself in the world. You believe you have a right, not to rule it, but to be part of it. Predator or prey; there is no shame to being either one.”
― Robin Hobb, quote from Assassin's Quest

“Don't give yourself a limit and you may discover you don't have one.”
― Veronica Blade, quote from Something Witchy This Way Comes

“In the early universe—when the universe was small enough to be governed by both general relativity and quantum theory—there were effectively four dimensions of space and none of time. That means that when we speak of the “beginning” of the universe, we are skirting the subtle issue that as we look backward toward the very early universe, time as we know it does not exist! We must accept that our usual ideas of space and time do not apply to the very early universe. That is beyond our experience, but not beyond our imagination, or our mathematics.”
― Stephen Hawking, quote from The Grand Design

“I couldn't resist another grin. "So...is there a family discount?"
"Hell, no. Nash is paying full price. Plus tip.”
― Rachel Vincent, quote from My Soul to Steal

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BookQuoters is a community of passionate readers who enjoy sharing the most meaningful, memorable and interesting quotes from great books. As the world communicates more and more via texts, memes and sound bytes, short but profound quotes from books have become more relevant and important. For some of us a quote becomes a mantra, a goal or a philosophy by which we live. For all of us, quotes are a great way to remember a book and to carry with us the author’s best ideas.

We thoughtfully gather quotes from our favorite books, both classic and current, and choose the ones that are most thought-provoking. Each quote represents a book that is interesting, well written and has potential to enhance the reader’s life. We also accept submissions from our visitors and will select the quotes we feel are most appealing to the BookQuoters community.

Founded in 2023, BookQuoters has quickly become a large and vibrant community of people who share an affinity for books. Books are seen by some as a throwback to a previous world; conversely, gleaning the main ideas of a book via a quote or a quick summary is typical of the Information Age but is a habit disdained by some diehard readers. We feel that we have the best of both worlds at BookQuoters; we read books cover-to-cover but offer you some of the highlights. We hope you’ll join us.