===== Scientific Revolution - History =====

This article traces the historical development of the [[scientific-revolution|Scientific Revolution]], the period roughly spanning the mid-16th through the late 17th century during which European natural philosophy was transformed by new methods of inquiry, institutional forms, and cosmological frameworks. For contested interpretations of this period, see [[scientific-revolution-debate|Scientific Revolution - Debate]]. For assessments of its legacy, see [[scientific-revolution-history-of-science-consensus|Scientific Revolution - History of Science Consensus]].

==== Background: Medieval Natural Philosophy ====

Medieval European natural philosophy rested primarily on the recovery and synthesis of ancient Greek texts, above all Aristotle, filtered through Islamic scholarship and Latin scholasticism. Institutions such as the University of Paris and the University of Oxford provided structured curricula in which natural knowledge was subordinated to theology and grounded in textual authority. Ptolemy's geocentric model of the cosmos, as elaborated in the //Almagest//, governed astronomical teaching. Galenic medicine, derived from the 2nd-century Greek physician Galen of Pergamon, dominated university medical faculties.

Challenges to this synthesis appeared before the 16th century. The Oxford Calculators of the 14th century, including Thomas Bradwardine and William Heytesbury, developed mathematical analyses of motion that departed from Aristotle's qualitative physics. Jean Buridan at Paris proposed the concept of //impetus// to explain projectile motion, a precursor to later inertial thinking. Nicole Oresme, also at Paris, entertained the hypothesis of a rotating Earth, though he did not advance it as a physical claim.

==== Early 16th Century: Humanist Recovery and Anatomical Reform ====

Renaissance humanism contributed to natural philosophy primarily through the recovery and critical editing of Greek and Roman texts. Humanist scholars sought more accurate versions of Aristotle, Galen, and Archimedes, which in some cases undermined rather than reinforced received doctrines by revealing errors in medieval Latin translations.

Andreas Vesalius, a Flemish physician working at the University of Padua, published //De humani corporis fabrica// in 1543, the same year as Copernicus's heliocentric treatise. Vesalius conducted systematic human dissections and found numerous errors in Galen's anatomy, which had been based largely on animal dissection. The //Fabrica// established direct observation of the body as methodologically prior to textual authority, and its detailed illustrations set a new standard for anatomical representation.

==== Copernicus and Heliocentrism ====

Nicolaus Copernicus, a Polish canon and mathematician, circulated a manuscript summary of his heliocentric hypothesis, the //Commentariolus//, among correspondents around 1514. He published the full account, //De revolutionibus orbium coelestium//, in 1543, reportedly receiving a printed copy on the day of his death.

Copernicus relocated the Sun to the center of the planetary system and treated the Earth as a planet orbiting it. His system resolved certain anomalies in the Ptolemaic model, particularly the looping retrograde motions of the outer planets, which Copernicus explained as a consequence of Earth's own motion rather than epicyclic mechanisms. However, his model retained circular orbits and epicycles, and historians have debated whether it offered substantially improved predictive accuracy over the Ptolemaic system as then practiced.

The Lutheran theologian Andreas Osiander, who oversaw the printing, inserted an unsigned preface characterizing the heliocentric model as a mathematical device rather than a physical claim. This preface was not written by Copernicus and was later identified as Osiander's addition. The book was not placed on the Catholic Index of Forbidden Books until 1616, decades after publication.

Reception among astronomers was gradual and mixed. Erasmus Reinhold used Copernican parameters to produce the Prutenic Tables (1551), which improved on the existing Alfonsine Tables without requiring acceptance of heliocentrism as a physical reality.

==== Tycho Brahe and Observational Astronomy ====

Tycho Brahe, a Danish nobleman, established the observatory of Uraniborg on the island of Hven under the patronage of King Frederick II of Denmark, operating it from 1576 until 1597. Working without a telescope, Tycho systematically measured planetary positions with an accuracy far exceeding his predecessors, reducing angular error to approximately one arcminute.

Tycho observed a new star in 1572 - what would later be classified as a supernova - and demonstrated through its lack of measurable parallax that it lay beyond the Moon, contradicting the Aristotelian doctrine of an unchanging celestial sphere. He similarly analyzed the comet of 1577 and concluded it moved through the planetary region, further undermining crystalline sphere cosmology.

Tycho rejected the Copernican system on physical and scriptural grounds but found the Ptolemaic system incompatible with his observational data. He proposed a compromise, the Tychonic system, in which the planets orbit the Sun while the Sun orbits a stationary Earth. This model was mathematically equivalent to the Copernican system in its predictions and was adopted by Jesuit astronomers as a means of accommodating new observations without affirming heliocentrism.

Following a dispute with his Danish patrons, Tycho relocated to Prague under the patronage of Holy Roman Emperor Rudolf II, where he hired Johannes Kepler as an assistant in 1600.

==== Kepler and the Laws of Planetary Motion ====

Johannes Kepler, a German mathematician and Protestant, gained access to Tycho's observational archive after Tycho's death in 1601. Using Tycho's precise data on the orbit of Mars, Kepler abandoned circular orbits after years of calculation and announced in //Astronomia Nova// (1609) that Mars follows an elliptical orbit with the Sun at one focus - his first law - and that a line from the Sun to a planet sweeps equal areas in equal times - his second law.

In //Harmonices Mundi// (1619), Kepler stated his third law: the square of a planet's orbital period is proportional to the cube of its mean distance from the Sun. This relationship held across all known planets and provided a precise mathematical structure connecting planetary motion to solar distance.

Kepler believed planetary motion was governed by a force emanating from the Sun, anticipating later gravitational theory, though he did not formulate that force mathematically. He also designed an improved refracting telescope, described in //Dioptrice// (1611), and wrote the //Somnium//, an early work of speculative fiction depicting an observer on the Moon.

==== Galileo and the Telescope ====

Galileo Galilei, an Italian mathematician and philosopher of nature, learned of the Dutch invention of the telescope in 1608 and rapidly constructed his own instruments of increasing power. Beginning in late 1609, he turned the telescope to the sky and published his findings in //Sidereus Nuncius// (1610).

Galileo reported four moons orbiting Jupiter - now called the Galilean moons - mountains and craters on the lunar surface, and a vast number of stars invisible to the naked eye. The Jovian moons demonstrated that not all celestial bodies orbited Earth. The lunar surface contradicted the Aristotelian distinction between a perfect, unchanging celestial realm and a corruptible terrestrial one.

Galileo subsequently observed the phases of Venus, which are explicable under a heliocentric or Tychonic model but not under the standard Ptolemaic system, and sunspots, which he tracked to argue the Sun rotates. He was appointed Mathematician and Philosopher to the Grand Duke of Tuscany in 1610, leaving the University of Padua.

Galileo's //Dialogo sopra i due massimi sistemi del mondo// (1632), a dialogue comparing the Ptolemaic and Copernican systems, was read by Church authorities as advocacy for heliocentrism in violation of the 1616 injunction. He was tried by the Inquisition in 1633, required to abjure the Copernican system, and placed under house arrest at his villa in Arcetri, where he continued to work until his death in 1642.

During his house arrest, Galileo composed //Discorsi e dimostrazioni matematiche intorno a due nuove scienze// (1638), published in Leiden. This work laid foundations for the mathematical analysis of motion, establishing that freely falling bodies accelerate uniformly and that projectile trajectories are parabolic.

==== Francis Bacon and Method ====

Francis Bacon, Lord Chancellor of England, did not contribute to specific scientific discoveries but articulated an influential program for the reform of natural knowledge. In //The Advancement of Learning// (1605) and //Novum Organum// (1620), Bacon argued that existing natural philosophy had produced no practical results because it relied on scholastic disputation and premature generalization from limited observation.

Bacon proposed systematic induction from carefully gathered, organized observations as the correct method for generating reliable knowledge of nature. He emphasized the elimination of what he called //idols// - systematic errors arising from human nature, individual habit, language, and received philosophical systems. He envisioned a collaborative, institutional enterprise of natural inquiry supported by the state, sketched in the posthumously published //New Atlantis// (1627).

Bacon's influence on the later Royal Society and on rhetoric about experimental method was substantial, though historians have debated how closely actual scientific practice followed Baconian prescription.

==== Descartes and Mechanical Philosophy ====

René Descartes, a French mathematician and philosopher, proposed a comprehensive alternative to Aristotelian natural philosophy grounded in the idea that all natural phenomena could be explained by matter and motion alone. He published //Le Monde// in 1633 but withheld it upon learning of Galileo's condemnation, releasing portions later. His //Principia Philosophiae// (1644) presented a systematic mechanical cosmology.

Descartes held that the universe consists of matter subdivided into three types and set in motion by God at creation, subsequently governed by laws of motion and organized into vortices that carry planets around the Sun. He denied the existence of void space and attributed gravity and magnetism to mechanical interactions of subtle matter.

Descartes also made foundational contributions to mathematics, developing analytic geometry in //La Géométrie// (1637), which unified algebraic and geometric methods and provided tools subsequently used throughout natural philosophy.

His strict substance dualism - distinguishing an extended material world from thinking substance - raised questions about the interaction of mind and body that occupied subsequent philosophers. His mechanical program, particularly its rejection of occult qualities and Aristotelian forms, was widely adopted even by those who rejected his specific physical theories.

==== The English Context: Experiment and Institutions ====

In England, natural philosophy became increasingly associated with experimental practice and organized sociability. The Oxford Philosophical Club, an informal grouping meeting in the 1650s and including Robert Boyle, John Wilkins, and Christopher Wren, was among the precursors to the Royal Society of London, chartered by Charles II in 1662.

Robert Boyle conducted systematic experiments on air using an air pump built with Robert Hooke's assistance, publishing //New Experiments Physico-Mechanical// (1660). Boyle articulated what became known as Boyle's Law - the inverse relationship between the pressure and volume of a gas at constant temperature - and advocated a corpuscular natural philosophy in which chemical and physical phenomena are explained by the size, shape, and motion of invisible particles. He was also a prominent advocate for the compatibility of experimental natural philosophy with Christian faith.

Robert Hooke, curator of experiments at the Royal Society, made contributions across optics, mechanics, biology, and engineering. His //Micrographia// (1665) presented detailed microscopic observations and introduced the word "cell" for the compartments he observed in cork.

==== Newton and Synthesis ====

Isaac Newton, an English mathematician and natural philosopher, achieved the period's most comprehensive synthesis. Working during the plague years of 1665-1666 at his family home in Lincolnshire, Newton made foundational advances in mathematics - developing what he called the method of fluxions, later known as calculus - and began investigations into optics and gravitation.

In optics, Newton demonstrated through prism experiments that white light is composed of rays of different refrangibility corresponding to different colors, published in the //Opticks// (1704), though the core experiments date to the 1660s.

Newton's //Philosophiae Naturalis Principia Mathematica// (1687), published under the sponsorship of Edmond Halley, presented three laws of motion - inertia, the proportionality of force and acceleration, and the equality of action and reaction - and the law of universal gravitation, which held that every body attracts every other with a force proportional to the product of their masses and inversely proportional to the square of their distance. Newton demonstrated mathematically that Kepler's three laws of planetary motion follow from universal gravitation and that terrestrial and celestial mechanics are governed by the same principles.

Newton declined to offer a physical mechanism for gravity, famously writing //hypotheses non fingo// - "I frame no hypotheses" - regarding its cause. His mathematical treatment of gravitation as action at a distance troubled some contemporaries, including Leibniz and Huygens, who regarded it as reintroducing occult qualities.

A priority dispute with Gottfried Wilhelm Leibniz over the invention of calculus occupied the later careers of both men and divided European mathematicians for decades, with British mathematicians generally supporting Newton and Continental mathematicians following Leibniz's notation, which ultimately prevailed.

==== Other Developments ====

William Harvey, an English physician trained at Padua, published //Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus// (1628), demonstrating through quantitative argument and dissection that the blood circulates continuously driven by the heart, refuting the Galenic account in which blood is continuously produced and consumed.

Evangelista Torricelli, an Italian physicist and student of Galileo, invented the barometer in 1643, demonstrating that atmospheric pressure supports a column of mercury approximately 760 mm high and providing evidence for the existence of vacuum above the mercury.

Christiaan Huygens, a Dutch mathematician and physicist, developed the wave theory of light, built the first pendulum clock (1656) enabling more precise timekeeping, and contributed to the mathematical theory of probability and the mechanics of collision.

Antoni van Leeuwenhoek, a Dutch draper with no university training, ground lenses of exceptional quality and from the 1670s observed and described microorganisms - bacteria and protozoa - for the first time, reporting his findings to the Royal Society.

==== Controversies ====

Some historians argue the concept of a unified "Scientific Revolution" imposes an artificial coherence on disparate developments across different disciplines, nations, and decades; see [[scientific-revolution-debate|Scientific Revolution - Debate]].

The relative causal weight of Protestant versus Catholic institutional contexts in enabling or hindering new natural philosophy remains disputed among historians of science.

Whether Bacon's inductive program meaningfully shaped actual scientific practice or primarily provided post-hoc rhetorical justification for experimental natural philosophy is a matter of ongoing debate.

The degree to which the period's developments constituted a break from medieval natural philosophy, rather than a cumulative extension of it, is disputed; see [[scientific-revolution-continuity-debate|Scientific Revolution - Continuity Debate]].

The extent to which non-European scientific traditions - Islamic, Chinese, and Indian - contributed to the developments of this period, or were independently developing comparable knowledge, is an active area of historical investigation.

==== Footnotes ====

1. Copernicus, Nicolaus. //De revolutionibus orbium coelestium//. Nuremberg: Johannes Petreius, 1543.
2. Vesalius, Andreas. //De humani corporis fabrica libri septem//. Basel: Johannes Oporinus, 1543.
3. Kepler, Johannes. //Astronomia Nova//. Prague, 1609.
4. Kepler, Johannes. //Harmonices Mundi//. Linz, 1619.
5. Galileo Galilei. //Sidereus Nuncius//. Venice: Thomas Baglioni, 1610.
6. Galileo Galilei. //Dialogo sopra i due massimi sistemi del mondo//. Florence: Giovanni Battista Landini, 1632.
7. Galileo Galilei. //Discorsi e dimostrazioni matematiche intorno a due nuove scienze//. Leiden: Elsevier, 1638.
8. Bacon, Francis. //Novum Organum//. London: John Bill, 1620.
9. Descartes, René. //Principia Philosophiae//. Amsterdam: Louis Elsevier, 1644.
10. Boyle, Robert. //New Experiments Physico-Mechanical, Touching the Spring of the Air//. Oxford: H. Hall, 1660.
11. Hooke, Robert. //Micrographia//. London: Royal Society, 1665.
12. Newton, Isaac. //Philosophiae Naturalis Principia Mathematica//. London: Royal Society, 1687.
13. Newton, Isaac. //Opticks//. London: Royal Society, 1704.
14. Harvey, William. //Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus//. Frankfurt: Wilhelm Fitzer, 1628.
15. Dear, Peter. //Revolutionizing the Sciences: European Knowledge and Its Ambitions, 1500-1700//. Princeton: Princeton University Press, 2001.
16. Henry, John. //The Scientific Revolution and the Origins of Modern Science//. 3rd ed. London: Palgrave Macmillan, 2008.
17. Shapin, Steven. //The Scientific Revolution//. Chicago: University of Chicago Press, 1996.
18. Cohen, H. Floris. //The Scientific Revolution: A Historiographical Inquiry//. Chicago: University of Chicago Press, 1994.
19. Westfall, Richard S. //Never at Rest: A Biography of Isaac Newton//. Cambridge: Cambridge University Press, 1980.