Rene Descartes

Western Philosophers 17th-century philosophy (Modern Philosophy)
Name: René Descartes
Birth: {{{birth}}}
Death: {{{death}}}
School/tradition: Cartesianism, Continental rationalism
Main interests
Metaphysics, Epistemology, Science, Mathematics
Notable ideas
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Influences	Influenced
Plato, Aristotle, Anselm, Aquinas, Ockham, Suarez, Mersenne, Augustine of Hippo, Michel de Montaigne	Baruch Spinoza, Thomas Hobbes, Immanuel Kant, Gottfried Leibniz

René Descartes (IPA: /deˈkaʁt/, March 31, 1596– February 11, 1650), also known as Cartesius, was a French philosopher, mathematician and part-time mercenary in the opening phases of the Thirty Years' War. He is noted equally for his groundbreaking work in philosophy and mathematics. As the inventor of the Cartesian coordinate system, he formulated the basis of modern geometry (analytic geometry), which in turn influenced the development of modern calculus.

Descartes, dubbed the "Founder of Modern Philosophy" and the "Father of Modern Mathematics," ranks as one of the most important and influential thinkers in modern western history. He inspired his contemporaries and subsequent generations of philosophers, leading them to form what we know today as continental rationalism, a philosophical position which developed in 17th and 18th century Europe.

His most famous statement is "Cogito ergo sum" ("I think, therefore I am").

Biography

Descartes was born in La Haye en Touraine, Indre-et-Loire, France, a town later renamed for him: "La Haye-Descartes" (1802) and simply "Descartes" (1967). At the age of eight, he entered the Jesuit College Royal Henry-Le-Grand at La Flèche. After graduation, he studied at the University of Poitiers, earning a Baccalauréat and Licence in law in 1616.

Descartes never actually practiced law, however, and in 1618 he entered the service of Prince Maurice of Nassau, leader of the United Provinces of the Netherlands, with the intention of following a military career. Here he met Isaac Beeckman and composed a short treatise on music entitled Compendium Musicae. In 1619, Descartes travelled in Germany, and on November 10 had a vision of a new mathematical and scientific system. In 1622 he returned to France, and during the next few years spent time in Paris and other parts of Europe. Descartes was present at the siege of La Rochelle by Cardinal Richelieu in 1627.

In 1628, Descartes composed Rules for the Direction of the Mind and left for Holland, where he lived, changing his address frequently, until 1649. In 1629 he began work on The World. In 1633, Galileo was condemned, and Descartes abandoned plans to publish The World. In 1635, Descartes' daughter Francine was born. She was baptized on August 7, 1635 and died in 1640. Descartes published Discourse on Method, with Optics, Meteorology and Geometry in 1637. In 1641, Meditations on First Philosophy was published, with the first six sets of Objections and Replies. In 1642, the second edition of Meditations was published with all seven sets of Objections and Replies, followed by Letter to Dinet. In 1643, Cartesian philosophy was condemned at the University of Utrecht, and Descartes began his long correspondence with Princess Elizabeth of Bohemia. Descartes published Principles of Philosophy and visited France in 1644. In 1647, he was awarded a pension by the King of France, published Comments on a Certain Broadsheet, and began work on The Description of the Human Body. Descartes was interviewed by Frans Burman at Egmond-Binnen in 1648, resulting in Conversation with Burman. In 1649, Descartes went to Sweden on invitation of professor Eitan Olevsky; Descartes' Passions of the Soul, which he dedicated to Princess Elizabeth of Bohemia, was published.

René Descartes died on February 11, 1650 in Stockholm, Sweden, where he had been invited as a teacher for Queen Christina of Sweden. The cause of death was said to be pneumonia - accustomed to working in bed till noon, he may have suffered a detrimental effect on his health due to Christina's demands for early morning study. However, letters to and from the doctor Eike Pies have recently been discovered which indicate that Descartes may have been poisoned using arsenic.

In 1667, after his death, the Roman Catholic Church placed his works on the Index of Prohibited Books.

As a Catholic in a Protestant nation, he was interred in a graveyard mainly used for unbaptized infants, in Adolf Fredrikskyrkan in Stockholm, Sweden. Later, his remains were taken to France and buried in the Church of St. Genevieve-du-Mont in Paris. A memorial erected in the 18th century remains in the Swedish church.

During the French Revolution, his remains were disinterred for burial in the Panthéon among the great French thinkers. The village in the Loire Valley where he was born was renamed La Haye - Descartes. Currently his tomb is in the church Saint Germain-des-Pres in Paris.

Significance

Philosophical Legacy & the 'Meditations'

Descartes is often regarded as the first modern thinker to provide a philosophical framework for the natural sciences as these began to develop. In his Meditations on First Philosophy he attempts to arrive at a fundamental set of principles that one can know as true without any doubt. To achieve this, he employs a method called methodological skepticism, or hyperbolic doubt: he denies any claim to be true that can at any time or in the least bit be doubted. Descartes himself likens this to a bushel of apples. If you find one rotten apple in the bushel, you must throw them all out first and then inspect the rest one by one to see if they've been ruined by this first rotten apple.

Descartes' methodological doubt is not arbitrary though. Descartes was educated in a time when what had been considered infallibly/absolutely true, namely in physics and astronomy, was now demonstrated to be completely false. The principal case of this being that the geocentric view of the solar system originating from Ptolemy was now debunked in favor of the heliocentric view. In other words, after approximately fifteen-hundred years of believing the Sun and other planets revolved around the Earth, it was discovered by Nicolaus Copernicus and further promulgated by Galileo Galilei that in fact, the Earth revolved around the Sun as did all other planets. Further findings by Copernicus also dealt a blow to the accepted Aristotelian physics of the time, and especially the hylomorphic view of form and matter. To say the least, this was very disturbing for the academic community and Descartes is very much a product of this disturbance. This is why Descartes pursues his methodological doubt; if the new natural sciences are to succeed, they must be built on a foundation that would never break as it did for the previous views in the natural sciences. Descartes wants science's theoretical claims to not just work, but also be true infallibly, so that fifteen-hundred years in the future man would not find out he was mistaken. Therefore, Descartes' rotten apple is the geocentric view of the solar system and Aristotelian physics.

First Meditation

The reason Descartes' doubt goes further than just scientific claims in his Meditations on First Philosophy, is that if he and the world could have been wrong about things that seemed so obvious and true (such as the sun revolving around the earth, which if we were to look at sunrise and sunset everyday makes fairly good sense), then he and the world could be wrong about a great deal more.

He gives the example of dreaming: in a dream, one's senses perceive things that seem real, but do not actually exist. Some dreams are fantastic and we are quick to dismiss them as not possibly true. But, there are also dreams that are very realistic, in which nothing extraordinary happens, and it is in these cases that Descartes argues that we cannot distinguish between dreaming and reality. And, if we cannot distinguish between dreaming and reality, then how do we know when we are dreaming and when we are not?

Descartes' doubt goes even further though, as he explains that even in dreams two plus two equals four. Therefore, what if there were some malicious, omnipotent demon whose whole purpose was to deceive me in everything I perceive or think. If we suppose this demon to exist, then we cannot even know if two plus two equals four since the demon could even be deceiving us about this. And, for Descartes, we must suppose this demon to exist, otherwise we have not thrown out all of the rotten apples from the bushel.

Another way to interpret Descartes' call upon the malicious demon is that Descartes is trying to argue that our very human nature may be constructed in such a way that even in such seemingly obvious things as simple math, we err.

Descartes' ultimate goal then, is to move from this doubt into an infallible foundation of knowledge if it is at all possible. In doing so, he must eliminate the possibility that we are being deceived by a malicious demon (or that our nature is such that it is given to error), that we cannot distinguish between dreaming and being awake, and that we have within us the power to avoid future error while accepting only truth.

Second Meditation

After all of this doubt in the first Meditation Descartes arrives at a single principle: if I am being deceived, then surely "I" must exist. Literally, he writes, "I am; I exist—this is certain." The more commonly known phrasing is the Latin, cogito ergo sum, ("I think, therefore I am"). This formulation though is from the Discourse on Method and should not be utilized when considering the Meditations.

The reason Descartes finds this idea indubitable is because even if there were a malicious demon deceiving me at every step, the "me," or "I," must exist at all of those steps in order to be deceived. In the very process of doubting everything, including whether I exist or not, I must affirm that "I" exist, or else there would be no doubting even going on. Therefore, Descartes concludes that he can be certain that he exists. But in what form?

Descartes looks at his hands and body and decides that at this point he cannot conclude that he is these things, as he perceives he has hands and a body through the senses and these are still doubtable. Descartes only wants to claim knowledge of what he can clearly and distinctly understand. And, at this point, since his senses are doubtful, he concludes only that he is a thinking thing. A thing that, "...doubts, understands, affirms, denies, wills, refuses, and that also imagines and senses" (AT 28). Thinking is his essence as it is the only thing about him that cannot be doubted.

It may seem curious at this point, but Descartes proceeds in his second 'Meditation' with a consideration of a piece of wax. Descartes' senses inform him that it has certain characteristics, such as shape, texture, size, color, smell, and so forth. However, when he brings the wax towards a flame, these characteristics change completely. However, it seems that it is still the same thing: it is still a piece of wax, even though the data of the senses inform him that all of its characteristics are different. Furthermore, hypothetically speaking then, the wax could exhibit an almost infinite number of characteristics that my imagination could never come up with (especially concerning size and shape). This means that regardless of whether Descartes really is holding any wax, he can clearly and distinctly perceive it insomuch as it is an extended thing which is understood by the mind. In other words, in order to properly grasp the nature of the wax, he cannot use the senses: he must use his mind. Descartes concludes:

"Thus what I thought I had seen with my eyes, I actually grasped solely with the faculty of judgment, which is in my mind" (AT 31).

As Descartes continues, he realizes that there is something unique about this extended "stuff": it is radically different than himself as a "thinking thing." At this point he does not call either a substance, but he has at least determined some essential differences between an extended thing and a thinking thing. And, Descartes counts this towards helping him better know what "I" a "thinking thing" am, as "I" can now know what I am not.

The idea that all material things are known through the mind and as extended things has a great impact on the scientific community as well, as it opens up the door for science to analyze "nature" in a mathematical way using the new Analytic Geometry Descartes helped formulate. Furthermore, it serves as a ground for science, so that it can be considered indubitable, as ultimately all calculations and observances are known through the deductive process of the mind, and hence not left to chance. Descartes mentions none of this in the Meditations, but as written earlier, this was always part of the goal in writing the Meditations.

In this manner, Descartes proceeds to construct a system of knowledge, discarding perception as unreliable and instead admitting only deduction as a method. Halfway through the Meditations, he also claims to prove the existence of a benevolent God, who, being benevolent, has provided him with a working mind and sensory system, and who cannot desire to deceive him, and thus, finally, he establishes the possibility of acquiring knowledge about the world based on deduction and perception.

Mathematical legacy

Rene Descartes said "Nature can be divined through numbers."

Mathematicians consider Descartes of the utmost importance for his discovery of analytic geometry. Up to Descartes's times, geometry, dealing with lines and shapes, and algebra, dealing with numbers, appeared as completely different subsets of mathematics. Descartes showed how to translate many problems in geometry into problems in algebra, by using a coordinate system to describe the problem.

Descartes's theory provided the basis for the calculus of Newton and Leibniz, by applying infinitesimal calculus to the tangent problem, thus permitting the evolution of that branch of modern mathematics ^[1]. This appears even more astounding when one keeps in mind that the work was just intended as an example to his Discours de la méthode pour bien conduire sa raison, et chercher la verité dans les sciences (Discourse on the Method to Rightly Conduct the Reason and Search for the Truth in Sciences, known better under the shortened title Discours de la méthode).

Descartes also made contributions in the field of Optics, for instance, he showed by geometrical construction using the Law of Refraction that the angular radius of a rainbow is 42° (i.e. the angle subtended at the eye by the edge of the rainbow and the ray passing from the sun through the rainbow's centre is 42°). ^[2]

Writings by Descartes

• Discourse on Method (1637): an introduction to "Dioptrique', on the "Météores' and 'La Géométrie'; a work for the grand public, written in French.
• La Géométrie (1637)
• Meditations on First Philosophy (1641), also known as 'Metaphysic meditations', with a series of six objections. This work was written in Latin, language of the learned.
• Les Principes de la philosophie (1644), work rather destined for the students.
• The Singing Epitaph (1646).

Trivia

It is claimed that during the 1640s Descartes travelled with an artificial female companion called Francine, named after his daughter. This may be a myth linked with his statements about the nature of the mind, or an early automaton, or Gynoid.

Descartes was ranked #49 on Michael H. Hart's list of the most influential figures in history.

References

ISBN links support NWE through referral fees

1. ^  Jan Gullberg (1997). Mathematics From The Birth Of Numbers. W. W. Norton & Company. ISBN 0-393-04002-X.
2. ^  P A Tipler, G Mosca (2004). Physics For Scientists And Engineers Extended Version. W H Freeman and Company. ISBN 0-7167-4389-2.

See also

• Dualistic interactionism
• Baruch Spinoza
• Asteroid 3587 Descartes, named after the philosopher
• Defect (geometry)
• Analytic geometry
• Cartesian coordinate system

External links

• A summary of his book "A Discourse On Method"
• (French) French Audio Book (mp3) : excerpt about animals/machines from Discourse On the Method
• Discourse On the Method – at Project Gutenberg
• Selections from the Principles of Philosophy – at Project Gutenberg
• Detailed biography of Descartes
• CATHOLIC ENCYCLOPEDIA: Rene Descartes
• READABLE versions of Descartes's Meditations and Discourse on the Method.
• Conscientia in Descartes
• descartes, an open source function plotter named after the inventor of Cartesian coordinates
• Biography, Bibliography, Analysis (in French)
• Stanford Encyclopedia of Philosophy:
  • Descartes' Epistemology
  • Descartes' Ethics
  • Descartes' Life and Works
  • Descartes' Modal Metaphysics
  • Descartes' Ontological Argument
  • Descartes and the Pineal Gland

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