Historians and sociologists have remarked the occurrence in science of "multiple independent discovery".Merton, R.K. (1961), "Singletons and Multiples in Scientific Discovery: A Chapter in the Sociology of Science", Vol.105, No.5, (13 October 1961), pp. 470-486. Robert K. Merton defined such "multiples" as instances in which similar discoveries are made by scientists working independently of each other. Reprinted in: "Sometimes", writes Merton, "the discoveries are simultaneous or almost so; sometimes a scientist will make a new discovery which, unknown to him, somebody else has made years before."
Commonly cited examples of multiple independent discoveries are the independent formulation of calculus by Isaac Newton and Gottfried Wilhelm Leibniz in the 17th century; the independent discovery of oxygen by Carl Wilhelm Scheele, Joseph Priestley, Antoine Lavoisier and others in the 18th century; and the theory of the evolution of species by natural selection, which was independently proposed by Charles Darwin and Alfred Russel Wallace in the 19th century.
Multiple independent discovery, however, is not limited to such famous historic instances. Merton believed that multiple discoveries in science are more commonly the rule rather than the exception: the discovery or elucidation of novel ideas or technologies by multiple people working independently represents a "common" pattern in science, while unique discoveries, on the contrary, are relatively rare.Robert K. Merton, "Singletons and Multiples in Scientific Discovery: a Chapter in the Sociology of Science", Proceedings of the American Philosophical Society, 105: 470–486, 1961. Reprinted in Robert K. Merton, The Sociology of Science: Theoretical and Empirical Investigations, Chicago, University of Chicago Press, 1973, pp. 343–370. Merton contrasted a "multiple" with a "singleton"—a discovery that has been made uniquely by a single scientist or group of scientists working together.Robert K. Merton, On Social Structure and Science, p. 307. Others have observed that this distinction may blur as science becomes increasingly collaborative.Sarah Lewin Frasier and Jen Christiansen, "Nobel Connections: A deep dive into science's greatest prize", Scientific American, vol. 331, no. 3 (October 2024), pp. 72–73.
A distinction is sometimes drawn between a discovery and an invention, as discussed for example by Bolesław Prus.Bolesław Prus, O odkryciach i wynalazkach (On Discoveries and Inventions): A Public Lecture Delivered on 23 March 1873 by Aleksander Głowacki [Bolesław Prus], Passed by the [Russian] Censor (Warsaw, 21 April 1873), Warsaw, Printed by F. Krokoszyńska, 1873, p. 12. However, discoveries and inventions are inextricably related, in that discoveries lead to inventions, and inventions facilitate discoveries; and since the same phenomenon of multiplicity occurs in relation to both discoveries and inventions, this article lists both multiple discoveries and multiple inventions.
3rd century BCE Aristarchus of Samos (c. 310 – c. 230 BCE) was the first known originator of a heliocentric (solar) system. Such a system was formulated again some 18 centuries later by Nicolaus Copernicus (1473–1543).Owen Gingerich, "Did Copernicus Owe a Debt to Aristarchus?" Journal for the History of Astronomy, vol. 16, no. 1 (February 1985), pp. 37–42. Dava Sobel, A More Perfect Heaven: How Copernicus Revolutionized the Cosmos, New York, Walker & Company, 2011, , pp. 18–19, 179–82.
13th century CE 1242: Arab polymath Ibn al-Nafis was the first to describe the function of pulmonary circulation. This aspect of the vertebrate circulatory system was independently rediscovered by Michael Servetus in 1553 and by William Harvey in 1616.
14th century
Gresham's (Copernicus') law was proposed by French philosopher Nicole Oresme 1370, and independently by Polish polymath Nicolaus Copernicus in 1519,"Copernicus seems to have drawn up some notes [on the displacement of good coin from circulation by debased coin] while he was at Olsztyn in 1519. He made them the basis of a report on the matter, written in German, which he presented to the Prussian Diet held in 1522 at Grudziądz .... He later drew up a revised and enlarged version of his little treatise, this time in Latin, and setting forth a general theory of money, for presentation to the Diet of 1528." Angus Armitage, The World of Copernicus, 1951, p. 91. English merchant Thomas Gresham in the 16th century, and Scottish economist Henry Dunning Macleod in 1857. Ancient references to the same concept include one in Aristophanes' comedy The Frogs (405 BCE), which compares bad politicians to bad coin (bad politicians and bad coin, respectively, drive good politicians and good coin out of circulation).
16th century
Simon Stevin and Galileo Galilei each independently described the hydrostatic paradox, Stevin 1585 and Galileo 1610. They also both performed an experiment comparing heavy and light balls falling together (contra Aristotle). Scipione dal Ferro in 1520 and Niccolò Tartaglia in 1535 independently developed a method for solving cubic equations. Olbers' paradox (the "dark-night-sky paradox") was independently described by Thomas Digges in the 16th century, by Johannes Kepler in 1610, by Edmond Halley and by Jean-Philippe de Chéseaux in the 18th century, by Heinrich Wilhelm Matthias Olbers in 1823, and definitively by Lord Kelvin in 1901. Some aspects of Kelvin's argument had been anticipated in the poet and short story writer Edgar Allan Poe's essay Eureka: A Prose Poem (1848), which also presaged by three-quarters of a century the Big Bang theory of the universe.* Marilynne Robinson, "On Edgar Allan Poe", The New York Review of Books, vol. LXII, no. 2 (5 February 2015), pp. 4, 6. Continental drift, in varying independent iterations, was proposed by Abraham Ortelius in , Theodor Christoph Lilienthal in 1756, Alexander von Humboldt in 1801 and again in 1845, Antonio Snider-Pellegrini in , Alfred Russel Wallace, Charles Lyell, Franklin Coxworthy between 1848 and 1890, Roberto Mantovani between 1889 and 1909, William Henry Pickering in 1907,, Frank Bursley Taylor in 1908, and Alfred Wegener in 1912. In addition, in 1885 Eduard Suess proposed the former existence of a supercontinent named GondwanaEduard Suess, Das Antlitz der Erde (The Face of the Earth), vol. 1 (Leipzig, (Germany): G. Freytag, 1885), page 768. From p. 768: "Wir nennen es Gondwána-Land, nach der gemeinsamen alten Gondwána-Flora, … " (We name it Gondwána-Land, after the common ancient flora of Gondwána ... ) and in 1893 the Tethys Ocean, assuming a land-bridge between the present continents submerged in the form of a geosyncline. In 1895 John Perry proposed that the Earth's interior was fluid and notably disagreed with Lord Kelvin on the age of the Earth.
17th century
Oxygen was first described by Michael Sendivogius in 1604. It was later independently described by Carl Wilhelm Scheele in 1771–1772, by Joseph Priestley in 1774, and, as a chemical element, by Antoine Lavoisier in 1777. Sunspots were first observed by Thomas Harriot in 1610, and later by Johannes and David Fabricius in 1611, Galileo Galilei in 1612, and Christoph Scheiner in 1612. Logarithms were first described by John Napier in 1614 and subsequently by Joost Bürgi in 1618. Analytic geometry was independently described by René Descartes and Pierre de Fermat. The problem of points was solved independently by both Pierre de Fermat and Blaise Pascal in 1654, and by Christiaan Huygens in 1657. Calculus was independently formulated by Isaac Newton and Gottfried Wilhelm Leibniz. Boyle's law (sometimes referred to as the "Boyle-Mariotte law") was first formulated by Anglo-Irish chemist Robert Boyle, who published the original law in 1662. The French physicist Edme Mariotte discovered the same law independently of Boyle in 1676. The Newton–Raphson method of finding roots in mathematics was originally described by Isaac Newton, whose work was written in 1669 and 1671 but not published until 1736. The same algorithm was independently described by Joseph Raphson in 1690. Determinants were described by Seki Takakazu in Japan in 1683 or earlier, and by Gottfried Wilhelm Leibniz in Germany in 1693. The brachistochrone problem was solved independently by Johann Bernoulli, Jakob Bernoulli, Isaac Newton, Gottfried Wilhelm Leibniz, Guillaume de l'Hôpital, and Ehrenfried Walther von Tschirnhaus. The problem was posed in 1696 by Johann Bernoulli and its solutions were published the next year. A patent for the steam engine was granted to Thomas Savery in 1698, though the invention has often been credited to Thomas Newcomen, who built the first practical device that harnessed steam to perform mechanical work, the atmospheric engine, in 1712. Other designers and inventors of early steam-powered devices have included Taqī al-Dīn in 1551, Jerónimo de Ayanz y Beaumont in 1606, Giambattista della Porta, Giovanni Branca in 1629, Cosimo de' Medici in 1641, Evangelista Torricelli in 1643, Otto Von Guericke in 1672, Denis Papin in 1679, and many others.
18th century
Stirling numbers were discovered by James Stirling in 1730 and independently by Masanobu Saka in 1782. Platinum was identified by both Antonio de Ulloa and Charles Wood in the 1740s. The Leyden jar was invented independently by Ewald Georg von Kleist in 1745 and Pieter van Musschenbroek in 1745–1746.Thomas S. Kuhn, The Structure of Scientific Revolutions, Chicago, The University of Chicago Press, 1996, p. 17. The lightning rod was invented by Benjamin Franklin in 1749 and by Prokop Diviš in 1754, though this has been debated: Diviš's apparatus is assumed to have been more effective than Franklin's lightning rod but was intended for a different purpose than lightning protection. The law of conservation of matter was independently formulated by Mikhail Lomonosov in 1756Vladimir D. Shiltsev, "Nov. 19, 1771: Birth of Mikhail Lomonosov, Russia's first modern scientist", APS [American Physical Society] News, November 2011 (vol. 20, no. 10) . and by Antoine Lavoisier in 1778.Anirudh, "10 Major Contributions of Antoine Lavoisier", 17 October 2017 . Black-hole theory was anticipated by John Michell in a 1783 paper in The Philosophical Transactions of the Royal Society when he wrote: "If the semi-diameter of a sphere of the same density as the Sun in the proportion of five hundred to one, and by supposing light to be attracted by the same force in proportion to its [mass] with other bodies, all light emitted from such a body would be made to return towards it, by its own proper gravity."Alan Ellis, "Black HolesPart 1History", Astronomical Society of Edinburgh, Journal 39, 1999 . A description of Michell's theory of black holes. A few years later, a similar idea was suggested independently by Pierre-Simon Laplace.Stephen Hawking, A Brief History of Time, Bantam, 1996, pp. 43–45. The concept of the Malthusian catastrophe was proposed by Thomas Robert Malthus in 1798 and independently by Hong Liangji in 1793."Hong's essential insight is the same as Malthus's". Wm Theodore de Bary, Sources of East Asian Tradition, vol. 2: The Modern Period, New York, Columbia University Press, 2008, p. 85. Methods for measuring the specific heat of a solid were devised independently by Benjamin Thompson, Count Rumford and by Johan Wilcke, who published his discovery first (apparently not later than 1796, when he died). The geometrical representation of complex numbers in the complex plane was discovered independently by Caspar Wessel in 1799, Jean-Robert Argand in 1806, John Warren in 1828, and Carl Friedrich Gauss in 1831.Roger Penrose, The Road to Reality, Vintage Books, 2005, p. 81.
19th century