René Descartes ( , ; ; 31 March 1596 – 11 February 1650) was a French philosopher, mathematician, and scientist whose work was foundational to mathematics and modern philosophy. He connected the previously separate fields of geometry and algebra into analytic geometry and introduced a systematic method of inquiry that became influential in early modern philosophy. He made major contributions to epistemology and philosophy of mind as well as metaphysics, and influenced the development of modern science.
Refusing to accept the authority of previous philosophers, Descartes frequently set his views apart from the philosophers who preceded him. In the opening section of the Passions of the Soul, an early modern treatise on emotions, Descartes goes so far as to assert that he will write on this topic "as if no one had written on these matters before". His best-known philosophical statement is " ("I think, therefore I am"; French: ").
He was one of the key figures in the Scientific Revolution, and his Meditations on First Philosophy and other philosophical works continue to be studied. His influence in mathematics is equally apparent: the Cartesian coordinate system is named after him. Descartes is also credited as the father of analytic geometry, which facilitated the discovery of infinitesimal calculus and analysis.
Biography
Early life
René Descartes was born in , Province of Touraine (now Descartes, ), France, on 31 March 1596. In May 1597, his mother, Jeanne Brochard, died a few days after giving birth to a still-born child. Descartes's father, Joachim, was a member of the Parlement of Rennes at Rennes. René lived with his grandmother and with his great-uncle. Although the Descartes family was Roman Catholic, the region was controlled by the Protestant Huguenots. In 1607, late because of his fragile health, he entered the Jesuit College of La Flèche, where he was introduced to mathematics and physics. After graduation in 1614, he studied for two years (1615–16) at the University of Poitiers, earning a and in canon and civil law in 1616, in accordance with his father's wishes that he should become a lawyer. From there, he moved to Paris.
Army service In accordance with his ambition to become a professional military officer in 1618, Descartes joined, as a mercenary, the Protestant Dutch States Army in Breda under the command of Maurice of Nassau, and undertook a formal study of military engineering, as established by Simon Stevin. Descartes, therefore, received much encouragement in Breda to advance his knowledge of mathematics. In this way, he became acquainted with Isaac Beeckman, the principal of a Dordrecht school, for whom he wrote the Compendium of Music (written 1618, published 1650).McQuillan, J. C. 2016. Early Modern Aesthetics. Lanham, MD: Rowman & Littlefield. p. 45 .
While in the service of the Catholic Duke Maximilian of Bavaria from 1619, Descartes was present at the Battle of the White Mountain near Prague, in November 1620.Parker, N. Geoffrey. 2007. "Battle of White Mountain " (revised). Encyclopædia Britannica.Jeffery, R. 2018. Princess Elisabeth of Bohemia: The Philosopher Princess. Lanham, MD: Lexington Books. p. 68 .
According to Adrien Baillet, on the night of 10–11 November 1619 (St. Martin's Day), while stationed in , Descartes shut himself in a room with an "oven" (probably a cocklestove)Rothkamm, J., Institutio Oratoria: Bacon, Descartes, Hobbes, Spinoza (Leiden & Boston: Brill, 2009), p. 40 . to escape the cold. While within, he had three dreams, and believed that a divine spirit revealed to him a new philosophy. The second dream may have been an episode of exploding head syndrome, in which loud noise is imagined. By the time he exited the room, Descartes had formulated analytic geometry and the idea of applying the mathematical method to philosophy. He concluded from these dreams that the pursuit of science would prove to be, for him, the pursuit of true wisdom and a central part of his life's work.
Career France In 1620, Descartes left the army. He visited Basilica della Santa Casa in Loreto, then visited various countries before returning to France, and during the next few years, he spent time in Paris. It was there that he composed his first essay on method: (Rules for the Direction of the Mind.Durandin, Guy. 1970. Les Principes de la Philosophie. Introduction et notes. Paris: Librairie Philosophique J. Vrin. He arrived in La Haye in 1623, selling all of his property to invest in bonds, which provided a comfortable income for the rest of his life. Descartes was present at the siege of La Rochelle by Cardinal Richelieu in 1627 as an observer.Shea, William R. 1991. The Magic of Numbers and Motion. Science History Publications. There, he was interested in the physical properties of the great dike that Richelieu was building and studied mathematically everything he saw during the siege. He also met French mathematician Girard Desargues. In the autumn of that year, in the residence of the papal nuncio Guidi di Bagno, where he came with Mersenne and many other scholars to listen to a lecture given by the alchemist, , on the principles of a supposed new philosophy,Matton, Sylvain, ed. 2013. Lettres sur l'or potable suivies du traité De la connaissance des vrais principes de la nature et des mélanges et de fragments d'un Commentaire sur l'Amphithéâtre de la Sapience éternelle de Khunrath, by Nicolas de Villiers. Paris: Préface de Vincent Carraud. Cardinal Bérulle urged him to write an exposition of his new philosophy in some location beyond the reach of the Inquisition.Moote, A. L. 1989. Louis XIII, the Just. Oakland: University of California Press. pp. 271–72 .
Netherlands
Descartes returned to the Dutch Republic in 1628. In April 1629, he joined the University of Franeker, studying under Adriaan Metius, either living with a Catholic family or renting the . The next year, under the name "Poitevin", he enrolled at Leiden University, which at the time was a Protestant University. He studied both mathematics with Jacobus Golius, who confronted him with Pappus's hexagon theorem, and astronomy with Martin Hortensius.Grayling, A. C. 2006. Descartes: The Life of René Descartes and Its Place in His Times. Simon & Schuster. pp. 151–52. In October 1630, he had a falling-out with Beeckman, whom he accused of plagiarizing some of his ideas. In Amsterdam, he had a relationship with a servant girl, Helena Jans van der Strom, with whom he had a daughter, Francine, who was born in 1635 in Deventer. She was baptized a Protestant and died of scarlet fever at the age of 5.
Unlike many moralists of the time, Descartes did not deprecate the passions but instead defended them; he wept upon Francine's death in 1640. According to a 2018 biography by Jason Porterfield, "Descartes said that he did not believe that one must refrain from tears to prove oneself a man."Porterfield, J., René Descartes (New York: Rosen Publishing, 2018), p. 66 . Russell Shorto speculates that the experience of fatherhood and losing a child formed a turning point in Descartes's work, changing its focus from medicine to a quest for universal answers.Russell Shorto, Descartes' Bones: A Skeletal History of the Conflict Between Faith and Reason (New York: Random House, 2008)
Despite frequent moves, he wrote all of his major work during his 20-plus years in the Netherlands, initiating a revolution in mathematics and philosophy. In 1633, Galileo was condemned by the Italian Inquisition, and Descartes abandoned plans to publish Treatise on the World, his work of the previous four years. Nevertheless, in 1637, he published parts of this work in three essays: (The Meteors, (Dioptrics, and (Geometry, preceded by an introduction, his famous (Discourse on the Method. In it, Descartes lays out four rules of thought, meant to ensure that our knowledge rests upon a firm foundation:Descartes, Discourse on the Method (Zhubei: Hyweb Technology: 2011), p. 88 .
In , Descartes exploited the discoveries he made with Pierre de Fermat. This later became known as Cartesian geometry.
Descartes continued to publish works concerning both mathematics and philosophy for the rest of his life. In 1641, he published a metaphysics treatise, (Meditations on First Philosophy, written in Latin and thus addressed to the learned. It was followed in 1644 by (Principles of Philosophy, which was dedicated to Princess Elisabeth of Bohemia, a kind of synthesis of the Discourse on the Method and Meditations on First Philosophy.
In 1643, Cartesian philosophy was condemned at the University of Utrecht, and Descartes was obliged to flee to the Hague, then eventually to the north of Amsterdam, ultimately settling in Egmond-Binnen.
Between 1643 and 1649 Descartes lived with his girlfriend at Egmond-Binnen in an inn. Descartes became friendly with Anthony Studler van Zurck, lord of Bergen, and participated in the design of his mansion and estate. He also met Dirck Rembrantsz van Nierop, a mathematician and surveyor. He was so impressed by Van Nierop's knowledge that he even brought him to the attention of Constantijn Huygens and Frans van Schooten.
Descartes began (through Alfonso Polloti, an Italian general in Dutch service) a six-year correspondence with Princess Elisabeth of Bohemia, devoted mainly to moral and psychological subjects.Harth, E., Cartesian Women: Versions and Subversions of Rational Discourse in the Old Regime, (Ithaca: Cornell University Press, 1992), pp. 67–77 . Connected with this correspondence, in 1649 he published (The Passions of the Soul, which he dedicated to the Princess. A French translation of , prepared by Abbot Claude Picot, was published in 1647. This edition was also dedicated to Princess Elisabeth. In the preface to the French edition, Descartes praised true philosophy as a means to attain wisdom. He identifies four ordinary sources to reach wisdom and finally says that there is a fifth, better and more secure, consisting in the search for first causes.Blom, John J., Descartes, His Moral Philosophy and Psychology. New York University Press, 1978.
Sweden
By 1649, Descartes had become one of Europe's most famous philosophers and scientists. That year, Christina, Queen of Sweden invited him to her court to organize a new scientific academy and tutor her in his ideas about love. Descartes accepted, and moved to the Swedish Empire in the middle of winter. Christina was interested in and stimulated Descartes to publish The Passions of the Soul.
He was a guest at the house of Pierre Chanut, living on , less than 500meters from Castle Tre Kronor in Stockholm. There, Chanut and Descartes made observations with a Torricellian mercury barometer. Challenging Blaise Pascal, Descartes took the first set of barometric readings in Stockholm to see if atmospheric pressure could be used in forecasting the weather.Modern meteorology: a series of six lectures: delivered under the auspices of the Meteorological Society in 1878, 1879, p. 73.
Death Descartes agreed to tutor Christina three times weekly at 5 a.m. in her cold, draughty castle, but by 15 January 1650 they had met only four or five times. They disliked each other: she rejected his mechanical philosophy, and he did not share her passion for Ancient Greek language and literature.
He contracted pneumonia and died on 11 February,The Correspondence of Dirck Rembrantsz van Nierof, (1610–1682), pp. 61, 84 though other causes have been proposed, given Descartes's controversial reputation amid the European wars of religion.Pies Е., Der Mordfall Descartes, Solingen, 1996, and Ebert Т., Der rätselhafte Tod des René Descartes, Aschaffenburg, Alibri, 2009. French translation: L'Énigme de la mort de Descartes, Paris, Hermann, 2011 He was buried among orphans at what is now Adolf Fredrik Church in Stockholm. His papers passed to Chanut's Catholic brother-in-law Claude Clerselier, who selectively edited his letters to portray him as a saint.