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|DOD Year=17261727

|SummaryBrief='''Sir Isaac Newton''' (1642-1727) was a an English mathematician, astronomer, and physicist/natural philosopher who lived and worked in England in is widely recognized as one of the 17th and 18th century. most influential scientists of all time|Summary=Newton’s most notable contributions were made to the fields of physics, mathematics, and scientific method, which were so groundbreaking that he is currently considered to be one of the most important physicists in modern Western history.[[CiteRef::Janiak (2016)]] Philosophers of science credit Newton’s revolutionary theory of gravity and his experimental approach to conducting natural philosophy as outlined in his major work, The ''Philosophiæ Naturalis PrincipiaMathematica'' (''Mathematical Principles of Natural Philosophy'' or simply the [[Newton (Philosophiæ Naturalis 1687)|''Principia Mathematica'']]), whose principles became central to be the foundation for the dominant Newtonian mosaic which influenced much of late 18th and 19th century science.[[CiteRef::Janiak (2016)]] Some consider The the ''Principia'' to be the work that initially created physics as its own scientific field separate from the umbrella of metaphysics and philosophy.[[CiteRef::Janiak (2016)]]|Historical Context=When Isaac Newton began his studies at Cambridge University's prestigious Trinity College in 1661, more than a century had passed since Nicolaus Copernicus (1473-1543) had proposed a '''heliocentric cosmology''' in his 1543 ''De revolutionibus orbium coelestium'' (''On the Revolutions of Heavenly Spheres''). It had been fifty years since Galileo Galilei (1564-1642) had published his observations with the telescope in 1610. Galileo had discovered , which uncovered dramatic evidence favoring the Copernican system. His discovery of the phases of the planet Venus indicated that it revolved around the sun and was lit by reflected sunlight. His description of four moons circling Jupiter indicated that Earth, with its own moon, resembled this planet. His studies of sunspots indicated that the sun revolved on its axis, and finally, his discovery of surface features on the moon indicated that the moon was another world, as expected under for the Copernican system, but not by Aristotelianism. Around At about the same time, Johannes Kepler had (1571-1630) published his laws of planetary motion, indicating that the planets revolved around the sun on elliptical paths, replacing the circular motion and complex epicycles of Copernicus and Claudius Ptolemy(c. 100-170). [[CiteRef::Westfall (1980)|ppp. 1-7]] According to Westfall, "by 1661 the debate on the heliocentric universe had been settled; those who mattered had surrendered to the irresistible elegance of Kepler's unencumbered ellipses, supported by the striking testimony of the telescope, whatever the ambiguities might be. For Newton, the heliocentric universe was never a matter in question"." [[CiteRef::Westfall (1980)|p. 6]]A planetary Earth that rotated on its axis and revolved around the sun was incompatible with the accepted physics of [[Aristotle]] (384-322 BCE). The community of the time was engaged with the question of how it could be that the Earth itself was in motion through space, and with the question of how one could hope to gain reliable knowledge in the face of the failure of Aristotelian scholastic knowledge accepted for centuries.

Newton’s education at Cambridge was nonetheless classical, focusing on Aristotelian rhetoric, logic, ethics, and physics. The Bound to '''Aristotelian scholasticism''' by statutory rules,the curriculum had changed little in decades, despite the incompatibility of Aristotelian natural philosophy with Copernican heliocentrism .[[CiteRef::Christianson (1984)|p. 33]][[CiteRef::Westfall (1980)|ppp. 81-90]][[CiteRef::Smith (2009)]] Like many of the more ambitious students, Newton is known to have distanced himself from classical metaphysics and instead studied the works of the French natural philosopher [[René Descartes ]](1596-1650) on his own. By 1664, Newton is known to have read the 1656 Latin edition of Descartes' ''Opera philosophica'Philosophica'', a one volume compilation which included ''Meditations on First Philosophy'of Descartes'major works.[[CiteRef::Smith (2009)]] Newton is known to have been profoundly influenced by Descartes views of space, ''Discourse on Method''matter, 'Dioptrics'and God, and 'The Principles of Philosophy' by commentaries on Descartes by Henry More (1614-1687). [[CiteRef::Smith Janiak (20092016)]] Descartes had died just eleven years prior to 1661over a decade earlier, and his major works had first been published within the preceding thirty years.They were gaining in popularity and by about 1680 would become the [[Theory Acceptance|accepted]] centerpiece of the Cambridge curriculum, as they also would in Paris by 1700.[[CiteRef::Barseghyan (2015)|p. 190]] When Newton published his magnum opus, the ''Principia'' in 1687, he was challenging a Cartesian orthodoxy. The full title of Newton's work suggests he intended it to be in dialog with Descartes' ''Principia Philosophiae'' (''Principles of Philosophy'') published in 1644.[[CiteRef::Janiak (2016)]]

first major workFor Descartes, the ultimate justification of knowledge claims lie with human reason and the absence of doubt. He relied on classical methods of theorizing and conjectured hypotheses in order to construct scientific propositions.[[CiteRef::Janiak (2016)]] Such a '''rationalist''Discourse on Method' approach to knowledge was also championed by Baruch Spinoza (1632-1677), Nicolas Malebranche (1638-1715), and Leibniz.[[CiteRef::Lennon and Dea (2014)]] But, by the early 17th century, experimental researchers like Galileo and Robert Boyle (1627-1691) had been written less than thirty years earlier begun to elaborate and practice a very different approach to knowledge based on experimentation and all extensive use of mathematics. Following the '''inductive methodology''' advocated by [[Francis Bacon]](1561-1626), they maintained that theoretical principles emerged from experimental data by a process of his major works had been puinductive generalization. By However, there were also dissenters like Newton's contemporary Christiaan Huygens, who believed that most experimental work involved formulating hypotheses about 1680unobservable entities, Descarteswhich were tested by their observable consequences. This was an early form of '''hypothetico-deductivism'''.|Major Contributions==== Newton on Mathematics and Natural Philosophy ===Newton' s two most important works would become of natural philosophy were the accepted centerpiece ''Principia'', published in 1687 [[CiteRef::Newton (1687)]], which dealt with his theories of motion and universal gravitation, and ''Opticks: or, A Treatise of the Cambridge curriculum Reflexions, Refractions, Inflexions, and Colours of Light'' [[CiteRef::Barseghyan Newton (20151704)|p]] which was published in 1704 and dealt with his theories of light and color. 190[[CiteRef::Westfall (1999)]]Newton made mathematics much more central to the conduct of natural philosophy than Descartes, by producing a general mathematical theory of the motion of bodies. [[CiteRef::Janiak (2016)]] He posited three mathematical '''laws of motion''', together with a '''law of universal gravitation'''. Changes in the state of motion of objects were caused by '''forces''' acting on them. Quantities of force and amounts of matter were measurable. The laws specified the mathematical relationship between the acceleration experienced by an object, the quantity of matter composing it, and the magnitude of the forces acting on it. [[CiteRef::Smith (2009)]]

In contrast with the Cartesian mechanical philosophy, who’s work conceived in Newton’s physics, material objects were not required to be in direct contact in order to influence each other's motion. Forces could act at a distance. To explain both falling bodies on Earth and the Cartesian mosaic motions of science the moon and planets, Newton posited a '''gravitational force''' that dominated much acted as the inverse square of the distance between objects. He claimed to have derived this relationship from Kepler's observational laws of planetary motion. The works of 17th Ptolemy, Copernicus, and Kepler used the mathematical language of geometry in their descriptive accounts of celestial motions. In the ''Principia'' Newton likewise presented his arguments geometrically. Unlike his predecessors, Newton sought to do more than simply describe celestial motions. He sought to explain them in terms of gravitational forces acting between bodies. In order to do this, Newton invented a new branch of mathematics, '''integral and differential calculus'''. Calculus deals with mathematical quantities that are continuously changing, such as the magnitude and direction of gravitational forces acting on an orbiting body. [[CiteRef::Friedman (2002)]][[CiteRef::Smith (2009)]] Newton developed the basic concept of calculus during 1665-6, while Cambridge University was closed due to a plague, but didn't publish it until the first decade of the eighteenth century European natural philosophy. He is thus co-credited with inventing calculus with his contemporary and rival Gottfried Wilhelm Leibniz (1646-1716).[[CiteRef::Janiak Cohen and Smith (Eds.) (20162002)|pp. 13,5510-20]]

, just eleven years after the death of [[Rene Descartes]] (1596-1650), and less that thirty years after the publication of Descartes first major work, the 'Discourse === Newton on Method'Methodology ===

Both Newton’s physics and Prior to the publication of The ''Principia'', the philosophy were heavily influenced by Descartes’ ideas. Although he disagreed with many of motion and change in the theories about the natural world adopted universe was largely a theoretical and non-mathematical enterprise. The dominating methodological approach both in the Aristotelian-scholastic and Cartesian mosaicnatural philosophy, it was clear that Newton viewed one in which truths about the natural world were proposed as conjectural hypotheses. Cartesian mosaic as a step forward '''rationalism'''sought to deduce such hypotheses from the preceding Aristotelian-scholastic onefundamental metaphysical principles that were deemed evidently true by human reason.[[CiteRef::Janiak (2016)|p. 55]] When structuring his view of the natural world, Descartes based his model on a Copernican view of the universe, as opposed to the classical geocentric understanding. The previous Aristotelian theory of motion had been contingent on geocentrism,[[CiteRef::Disalle Lennon and Dea (20042014)|p. 37]] as when Influenced by the Earth is at more experimental and mathematically oriented methodologies of Bacon, Galileo, and Boyle, Newton drew a distinction between a conclusion drawn from observation or experimental evidence and one that was merely a speculative 'hypothesis'. He explicitly rejected the centre method of the universehypotheses, and instead demanded that all motion could propositions be explained causally according to whether deduced from the moving object in question existed in the terrestrial or celestial realm, which in that mosaic were thought to be fundamentally differentobserved phenomena and then converted into general principles via '''induction'''.[[CiteRef::Bodnar McMullin (2001)]][[CiteRef::Janiak (2016)]][[CiteRef::Smith (2002)]] In the second edition of the ''Principia'', Newton states:

Once Descartes had adopted Copernican heliocentrism, the causal theory of motion <blockquote>I have not as understood by Aristotelian-scholastic natural philosophers had yet been able to be replaced along with its cosmological model.[[CiteRef::Disalle (2004)|p. 48]] Cartesian mechanics was developed around a radical comprehension that deduce from phenomena the source reason for these properties of motion was gravity, and I do not feign hypotheses. For whatever is not deduced from the same for all bodies in the universe. This idea acted as phenomena must be called a pillar upon which a newhypothesis; and hypotheses, whether metaphysical or physical, or based on occult qualities, or mechanical , have no place in experimental philosophy was constructed. According to In this experimental philosophy, propositions are deduced from the source phenomena and are made general by induction. The impenetrability, mobility, and impetus of bodies and the laws of all motion and law of material objects gravity have been found by this method. And it is direct, physical contact with other material objects. The mechanical philosophy was adopted by Gottfried Leibniz, Christiaan Huygens, enough that gravity should really exist and many other prominent scientists who worked alongside Newton, indicating should act according to the laws that much we have set forth and should suffice for all the motions of later 17th century science was deeply rooted in Cartesian philosophythe heavenly bodies and of our sea.[[CiteRef::Disalle Newton (20041999)| p. 276]]</blockquote>

Descartes included many revolutionary theories The generality of Newton's rejection of the hypotheses in natural world philosophy is unclear since, in his mosaicthe ''Opticks'' he did discuss hypotheses about light, but he still largely relied on classical methods and did raise the possibility of theorizing and conjectured hypotheses in order to construct scientific propositionsan invisible aether responsible for gravitational attraction.[[CiteRef::Janiak (2016)|pp. 25-26]] Whereas in the early 17th century Galileo His epistemological beliefs were similar to those of his contemporary and Boyle had already begun to test proposed theoriesfriend, Descartes still chose to use logical deductions in an attempt to prove empirical truths, instead of attempting any empirical testing or mathematical techniques[[John Locke]] (1632-1704) who maintained that all knowledge came from experience.[[CiteRef::Janiak Rogers (20161982)]] Many of Newton’s ideas were either adopted directly, or adapted from Descartes views of Newton called his methodology the natural world'''experimental philosophy''', however because theories about the method behavior of hypotheses is one that Newton rejected outright, as he instead sought different methods for arriving at his conclusionsempirical objects can only be refuted via experimental procedures.[[CiteRef::Janiak Smith (20162002)]]|Major Contributions={{#evtHe expressed its core beliefs in a set of four “rules for the study of natural philosophy,” which he stated in book III of The ''Principia'' as follows:service=youtube|id=ELbm5KUYMLM|alignment=right|description=Hakob Barseghyan's lecture on Newtonian Worldview|container=frame }}

'''<blockquote># No more causes of natural things should be admitted than are both true and sufficient to explain their phenomena# Therefore, the causes assigned to natural effects of the same kind must be, so far as possible, the same# Those qualities of bodies that cannot be intended and remitted (i.e. qualities that cannot be increased and diminished) and that belong to all bodies on which experiments can be made should be taken as qualities of all bodies universally# In experimental philosophy, propositions gathered from phenomena by induction should be considered either exactly or very nearly true notwithstanding any contrary hypothesis, until yet other phenomena make such propositions either more exact or liable to exceptions.[[CiteRef::Newton on Calculus'''(1999)|pp. 794-796]]</blockquote>

Whereas Descartes did not rely on mathematical reasoning for his deductions Out of scientific propositionsthese four rules a new, Newton believed engaged method for conducting science emerged that mathematics was an imperative part stood in stark contrast to the previous passive and theoretical Cartesian and Aristotelian-scholastic methods. Propositions formulated based on observations of conducting the natural world and placed back into the natural philosophyworld to be tested empirically.[[CiteRef::Janiak Smith (20162002)]] The calculus became deeply incorporated into the experimental method, as it was used to mathematically calculate empirical predictions from natural laws, and then evaluate how exactly the prediction matched the observed reality. Newton claimed to have derived his law of universal gravitation using this method as applied to Kepler's laws of planetary motion. In Newton’s physicsthe Cartesian natural philosophy, centripetal force had already been defined as the agent that pulled the moon towards the Earth, material objects were not required keeping its orbit circular rather than linear. Newton appealed to be in direct contact with each other in order for motion rules 1) and 2) to occur. Insteadclaim that the centripetal force, and the force that compelled objects react to each other via a move downwards towards the Earth, were merely two different expressions of the same thing. Newton then went on to apply the third rule, and argue that this force, a new concept which Newton envisioned as he called gravity, must be a quantifiable universal property contained in of all material objects. From here, he went on to argue for the amount unification of superlunary and sublunary phenomena, which is directly proportional Aristotle had deemed to be distinct realms.[[CiteRef::Harper (2002)|pp. 183-184]]|Criticism=Newton's theories provoked immediate and wide interest in Britain, and became accepted there by the quantity first decade of matter contained in the objecteighteenth century. Quantities [[CiteRef::Smith (2009)]][[CiteRef::Barseghyan (2015)|p. 210]] In continental Europe, acceptance came more slowly. To proponents of force and matter were thus introduced to the mosaic as ontological entities mechanical philosophy, it was methodologically necessary that were measurableall motion be given a cause involving direct physical contact of bodies. By applying Newton’s three laws Many of motionNewton's continental contemporaries, material objects in particular Leibniz and Huygens, strongly objected to the universe were compelled to accelerate through action idea that forces could act at a distance. Additionally, Leibniz regarded the laws outlined the mathematical relations between this acceleration and the quantities theory of force and matter could be explained and predicted mathematically, thereby giving mathematics gravitation as a new central role regression in the study of natural philosophy. In The ''Principiaand accused Newton of treating gravity as an 'occult quality'beyond philosophical understanding. After an intense debate, Newton made extensive use Newtonian gravitation theory became accepted through much of mathematics in his argument for continental Europe by the unified theory middle of gravitythe eighteenth century.[[CiteRef::Smith Janiak (2016)]] [[CiteRef::Barseghyan (20092015)|pp. 211-212]] The mathematical language used in The ''Principia'' was geometry, which was also the basis for many of the major models for celestial mechanics that were studied at the time, including the works of Ptolemy, Copernicus and Kepler[[CiteRef::Aiton (1958)|p.172]][[CiteRef::Smith Frangsmyr (20091974)|p. 35]]

Even though More than two centuries after Newton published his key work in the language of geometry''Principia'', as a mathematician he is primarily role in inventing integral new theory of motion and differential calculus. He is cogravitation was formulated by Albert Einstein (1879-credited independently for the calculus alongside his contemporary and rival natural philosopher1955), Leibniz.[[CiteRef::Cohen who was inspired by new developments in non-Euclidean geometry and Smith by problems with James Clerk Maxwell's (Eds1831-1879) theory of electromagnetic radiation.) (2002)|pp The new theory replaced Newton's theory as the accepted theory of motion and gravitation by about 1920. 13-14]] As a mathematical technique, calculus had been Einstein's '''General Theory of Relativity''' explained the first method success of its predecessor by showing that was capable its equations reduce to those of articulating Newton in the quantity limit of acceleration, unlocking a new world weak gravitational fields and velocities that are an insignificant fraction of calculations which geometry as a technique had been incapable that of solvinglight.[[CiteRef::Friedman (2002)]] Eventually, 18th century that mathematicians Jacob Hermann and Leonhard Euler expressed Newton’s laws of motion using NewtonEinstein's own technique theory eliminated the problem of action at a distance by postulating that the mass of calculusan object warps space-time, but in and that the symbolic expression that Leibniz had developedlocal manifestation of this curvature influences distant bodies.[[CiteRef::Smith Barseghyan (20092015)|p. 29125]] In following years, calculus became indispensable tool for scientists in the Newtonian mosaic to solve problems in physics, and to predict the behaviour of material objects with an unprecedented degree of accuracy.[[CiteRef::Smith Isaacson (20092007)]] Although geometry is still taught in schools today, calculus is the primary mathematical technique learned and used in physics and engineering classrooms.

Newton's experimental philosophy shaped accepted claims about scientific methodology, influencing the methodological pronouncements of George Berkeley (1685-1753), David Hume, Thomas Reid (1710-1796), and Immanuel Kant (1724-1804). [[CiteRef::McMullin (2001)]] However, according to McMullin, Newton's methodology ran contrary to the consensus that had been emerging among natural philosophers of his time, in favor of what we now recognize as the '''hypothetico-deductive method'''. [[CiteRef::McMullin (2001)]] Historical research shows that the scientific community did not use Newton 's own criteria in evaluating his work. His theories did not become accepted outside of England until after their prediction of the oblate spheroid shape of the Earth was confirmed by expeditions to Lapland and Peru. Newton's own theories became accepted based on methodconfirmed novel predictions that distinguished them from the rival theory of Cartesian vortices, rather than by Newton's own '''inductive methodology'''. Further, Newton's theory, in fact, posited unobservable hypothetical entities, including gravitational attraction, absolute space, and absolute time.[[CiteRef::Barseghyan (2015)|p. 48-49]][[CiteRef::Terrall (1992)]][[CiteRef::McMullin (2001)]]

Prior to the publication of The ''Principia'', the philosophy of motion and change in By the universe was largely a theoretical and nonmid-mathematical enterprise. The dominating methodological approach to eighteenth century natural philosophy both in the Aristotelian-scholastic and Cartesian mosaic, was one in which truths about the natural world philosophers were proposed as conjectural hypotheses. Newton explicitly rejected the method of hypotheses, and instead demanded beginning to realize that all propositions be deduced from the phenomena and then converted into general principles via induction. In many successful theories violated the second edition strictures of The Newton''Principia'', Newton states: “I have not as yet been able to deduce from phenomena the reason for these properties of gravity, and I do not feign hypotheses. For whatever is not deduced from the phenomena must be called a hypothesis; and hypotheses, whether metaphysical or physical, or based on occult qualities, or mechanical, have no place in experimental philosophy. In this s inductive experimental philosophy, propositions are deduced from the phenomena and are made general by induction. The impenetrability, mobility, and impetus of bodies and eighteenth century saw the laws acceptance of motion and law a variety of gravity have been found by this method. And it is enough theories that gravity should really exist and should act according to the laws that we have set forth and should suffice for all the motions of the heavenly bodies and of our sea.”[[CiteRef::Newton posited unobservable entities, including Benjamin Franklin's (19991706-1790)]] Newton called his method the experimental philosophytheory of electricity, because theories about which posited the behavior existence of empirical objects can only be refuted via experimental procedures.[[CiteRef::Smith (2002)]] He expressed an unobservable electric fluid, the core beliefs from which he derived his method in a set phlogiston theory of four “rules for the study of natural philosophycombustion and rust,” which he stated in book III of The likewise posited an unobservable substance, and Augustin-Jean Fresnel''Principia'' as follows: "1s (1788-1827) No more cause wave theory of natural things should be admitted than are both true and sufficient to explain their phenomena 2) Therefore, light which posited an unobservable fluid ether as the causes assigned to natural effects medium of the same kind must be, so far as possiblelight, the same 3) Those qualities of bodies that cannot be intended and remitted Herman Boerhaave's (i.e. qualities that cannot be increased and diminished1668-1738) and that belong to all bodies on which experiments can be made should be taken as qualities vibratory theory of all bodies universally 4) In experimental philosophy, propositions gathered from phenomena by induction should be considered either exactly or very nearly true nonwithstanding any contrary hypothesis, until yet other phenomena make such propositions either more exact or liable to exceptionsheat.”[[CiteRef::Newton Laudan (19991984a)|pp. 56-57]] Out of these four rules a new, engaged method for conducting science emerged that stood in stark contrast the previous passive and theoretical Cartesian and Aristotelian-scholastic methods. Propositions are born from natural sources and placed back into the natural world to be tested empirically.[[CiteRef::Smith Barseghyan (20022015)|p. 54]] As the four rules were absorbed into the ensuing mosaic, the calculus became deeply incorporated in the experimental method, as it was used to mathematically calculate from natural laws an empirical prediction, and then evaluate how exactly the prediction matched the observed reality. Using these principles, Newton was able to derive the law The methodologists of universal gravity in the context of his method. In the Cartesian mosaicearly nineteenth century, the centripetal force had already been defined as the agent that pulled the moon towards the Earth, keeping its orbit circular rather than linear. Newton applied rules 1William Whewell (1794-1866) and 2John Hershel (1792-1871) to determine that the centripetal force, and the force recognized that compelled objects to move downwards towards the Earth, were merely two different expressions actual practice of the same thing. Newton then went on science did not conform to apply the third rule, prescribed Newtonian methodology and argue that this force, which he called gravity, must be a universal property of all material objects. From here, he went on to argue for openly advocated the unification of superlunary and sublunary phenomenahypothetico-deductive method.[[CiteRef::Harper Laudan (20021984a)|pp. 18356-18460]]|Related Topics=Methodology,|Page Status=Editor Approved}}{{YouTube VideoAlthough not all of the ontological changes to the mosaic described in The ''Principia'' were immediately accepted, the new experimental philosophy that he described influenced contemporary scientists within the same century of it’s publication. [Newtons philosophy] Both prominent 17th century natural philosophers Christiaan Huygens and John Locke are known to have taken the experimental philosophy, if not necessarily the full content of Newton’s theories, to heart.[[CiteRef::Janiak (2016)]] By 1700 the acceptance of “experimental philosophy” methodological structure had overtaken that of Cartesianism in England.[[CiteRef::Janiak (2016)]]|VideoID=ELbm5KUYMLM|CriticismVideoDescription=Although many natural philosophers in the 17th century were convinced by Newton’s views Hakob Barseghyan's lecture on the the proper method of conducting science, many were not willing to abandon the Cartesian mechanical philosophy. Contemporary philosopher Leibniz in particular was concerned that the theory of gravity as a regression in natural philosophy, as Newton could not account for the source of gravity. To the Cartesians, it was more important that all motion in the universe could be given a direct cause, which was only possible under the mechanical philosophy, even if this amounted to a larger gap between theory and experimental evidence.[[CiteRef::Janiak (2016)]]Newtonian Worldview|Page StatusVideoEmbedSection=Needs EditingMajor Contributions