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René Descartes

2007 Schools Wikipedia Selection. Related subjects: Philosophers

   Western Philosophy
   17th-century philosophy
   René Descartes
   Name: René Descartes
   Birth: March 31, 1596 ( La Haye en Touraine (now Descartes),
   Indre-et-Loire, France)
   Death: February 11, 1650 (Stockholm, Sweden)
   School/tradition: Cartesianism, Rationalism, Foundationalism
   Main interests: Metaphysics, Epistemology, Science, Mathematics
   Notable ideas: Cogito ergo sum, method of doubt, Mathesis Universalis,
   Cartesian coordinate system, Cartesian dualism, ontological argument
   for God's existence; regarded as a founder of Modern philosophy
   Influences: Plato, Aristotle, Anselm, Aquinas, Ockham, Suarez,
   Mersenne, Pyrrho
   Influenced: Spinoza, Arnauld, Malebranche, Pascal, Locke, Leibniz,
   More, Kant, Husserl

   René Descartes ( March 31, 1596 – February 11, 1650), also known as
   Cartesius, was a noted French philosopher, mathematician, and
   scientist. Dubbed the "Founder of Modern Philosophy" and the " Father
   of Modern Mathematics," he ranks as one of the most important and
   influential thinkers of modern times. For good or bad, much of
   subsequent western philosophy is a reaction to his writings, which have
   been closely studied from his time down to the present day. Descartes
   was one of the key thinkers of the Scientific Revolution in the Western
   World. His influence in mathematics is also apparent, the Cartesian
   coordinate system used in plane geometry and algebra being named after
   him.

   Descartes frequently contrasted his views with those of his
   predecessors. In the opening section of the Passions of the Soul, he
   goes so far as to assert that he will write on his topic "as if no one
   had written on these matters before". Nevertheless many elements of his
   philosophy have precedents in late Aristotelianism, the revived
   Stoicism of the 16th century, or in earlier philosophers like
   Augustine. In his natural philosophy, he differs from the Schools on
   two major points: first, he rejects the analysis of corporeal substance
   into matter and form; second, he rejects any appeal to ends—divine or
   natural—in explaining natural phenomena. In his theology, he insists on
   the absolute freedom of God’s act of creation.

   Descartes was a major figure in 17th century continental rationalism,
   later advocated by Baruch Spinoza and Gottfried Leibniz, and opposed by
   the empiricist school of thought, consisting of Hobbes, Locke,
   Berkeley, and Hume. Leibniz, Spinoza and Descartes were all versed in
   mathematics as well as philosophy, and Descartes and Leibniz
   contributed greatly to science as well. As the inventor of the
   Cartesian coordinate system, Descartes founded analytic geometry, that
   bridge between algebra and geometry crucial to the invention of the
   calculus and analysis. Descartes' reflections on mind and mechanism
   began the strain of western thought that much later, impelled by the
   invention of the electronic computer and by the possibility of machine
   intelligence, blossomed into, e.g., the Turing test. His most famous
   statement is Cogito ergo sum (French: Je pense, donc je suis or in
   English: I think, therefore I am), found in §7 of Principles of
   Philosophy (Latin) and part IV of Discourse on Method (French).

Biography

   On March 31, 1596, Descartes was born in La Haye en Touraine (now
   Descartes), Indre-et-Loire, France. When he was 1 year old, his mother
   died of tuberculosis. His father was a judge in the High Court of
   Justice. At the age of ten, he entered the Jesuit Collège 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, in accordance with his father's wishes that he become a lawyer.

   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. His intention was to see the world and to discover
   the truth.

          "I entirely abandoned the study of letters. Resolving to seek no
          knowledge other than that which could be found in myself or else
          in the great book of the world, I spent the rest of my youth
          traveling, visiting courts and armies, mixing with people of
          diverse temperaments and ranks, gathering various experiences,
          testing myself in the situations which fortune offered me, and
          at all times reflecting upon whatever came my way so as to
          derive some profit from it. (Descartes, Discourse on the Method
          of Rightly Conducting One's Reason and Seeking the Truth in the
          Sciences)

   Here he met Isaac Beeckman, who sparked his interest in mathematics and
   the new physics, particularly the problem of fall of heavy bodies. On
   November 10, 1619, while traveling in Germany and thinking about using
   mathematics to solve problems in physics, Descartes had a vision in a
   dream through which he "discovered the foundations of a marvelous
   science" . This became a pivotal point in young Descartes' life and the
   foundation on which he develops analytical geometry. He dedicated the
   rest of his life to researching this connection between mathematics and
   nature.

   In 1622 he returned to France, and during the next few years spent time
   in Paris and other parts of Europe. He arrived in La Haye in 1623,
   selling all of his property, investing this remuneration in bonds which
   provided Descartes with a comfortable income for the rest of his life.
   Descartes was present at the siege of La Rochelle by Cardinal Richelieu
   in 1627. He left for Holland in 1628, where he lived and changed his
   address frequently until 1649.

   In 1633, Galileo was condemned by the Roman Catholic Church, and
   Descartes abandoned plans to publish Treatise on the World, his work of
   the previous four years.

   Although Descartes never married, he fathered a daughter, the issue of
   an affair with a woman named Helene; Francine, born in 1635 and
   baptized on August 7 of the same year. Much to Descartes' distress, she
   died in 1640 at the age of 5.

   Descartes continued to publish works concerning mathematics and
   philosophy for the rest of his life. In 1643, Cartesian philosophy was
   condemned at the University of Utrecht, and Descartes began his long
   correspondence with Princess Elizabeth of Bohemia. In 1647, he was
   awarded a pension by the King of France. Descartes was interviewed by
   Frans Burman at Egmond-Binnen in 1648.

   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. Others believe that
   Descartes may have contracted pneumonia as result of nursing a French
   ambassador, ill with aforementioned disease, back to health. However,
   letters to and from the doctor Eike Pies have recently been discovered
   which indicate that Descartes may have been poisoned using arsenic.

   In 1663, the Pope placed his works on the Index of Prohibited Books.

   As a Roman Catholic in a Protestant nation, he was interred in a
   graveyard mainly used for unbaptized infants in Adolf Fredrikskyrkan in
   Stockholm. Later, his remains were taken to France and buried in the
   church of Sainte-Geneviève-du-Mont in Paris. His 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 in 1802,
   which was shortened to "Descartes" in 1967. Currently his tomb is in
   Saint-Germain-des-Prés' church in Paris.

Philosophical work

   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: he doubts any idea that can be doubted.

   He gives the example of dreaming: in a dream, one's senses perceive
   stimuli that seem real, but do not actually exist. Thus, one cannot
   rely on the data of the senses as necessarily true. Or, perhaps an
   "evil demon" exists: a supremely powerful and cunning being who sets
   out to try to deceive Descartes from knowing the true nature of
   reality. Given these possibilities, what can one know for certain?

   Initially, Descartes arrives at only a single principle: thought
   exists. Thought cannot be separated from me, therefore, I exist
   (Meditations on First Philosophy). Most famously, this is known as
   cogito ergo sum, ("I think, therefore I am"). (These words do not
   appear in the Meditations, although he had written them in his earlier
   work Discourse on Method).

   Note; Descartes was also skeptical of memory, as that has also been
   known to be manipulated, and can be doubted, so the 'cogito' argument
   can only apply to the present. The phrase is therefore more accurately
   (but less famously) translated as; "I am thinking, therefore I exist"

   Therefore, Descartes concludes that he can be certain that he exists.
   But in what form? He perceives his body through the use of the senses;
   however, these have previously been proven unreliable. So Descartes
   concludes that the only undoubtable knowledge is that he is a thinking
   thing. Thinking is his essence as it is the only thing about him that
   cannot be doubted. Descartes defines "thought" (cogitatio) as "what
   happens in me such that I am immediately conscious of it, insofar as I
   am conscious of it". Thinking is thus every activity of a person of
   which he is immediately conscious.

   To further demonstrate the limitations of the senses, Descartes
   proceeds with what is known as the Wax Argument. He considers a piece
   of wax: his senses inform him that it has certain characteristics, such
   as shape, texture, size, colour, smell, and so forth. 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. Therefore, 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."

   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 offers an
   ontological proof of a benevolent God (through both the ontological
   argument and trademark argument). Because God is benevolent, he can
   have some faith in the account of reality his senses provide him, for
   God has provided him with a working mind and sensory system and does
   not desire to deceive him; however, this is a contentious argument, as
   his very notion of a benevolent God from which he developed this
   argument is easily subject to the same kind of doubt as his
   perceptions. From this supposition, however, he finally establishes the
   possibility of acquiring knowledge about the world based on deduction
   and perception. In terms of epistemology therefore, he can be said to
   have contributed such ideas as a rigorous conception of foundationalism
   and the possibility that reason is the only reliable method of
   attaining knowledge, as others said before him, though not as clearly
   as he did, and the rationalist answer to skepticism which other
   rationalists have elaborated on.

   In Descartes' system, knowledge takes the form of ideas, and
   philosophical investigation is the contemplation of these ideas. This
   concept would influence subsequent internalist movements as Descartes'
   epistemology requires that a connection made by conscious awareness
   will distinguish knowledge from falsity. As a result of his Cartesian
   doubt, he sought for knowledge to be "incapable of being destroyed", in
   order to construct an unshakable ground from which all other knowledge
   can be based on. The first item of unshakable knowledge that Descartes
   argues for is the aforementioned cogito, or thinking thing.

   Descartes also wrote a response to skepticism about the existence of
   the external world. He argues that sensory perceptions come to him
   involuntarily, and are not willed by him. They are external to his
   senses, and according to Descartes, this is evidence of the existence
   of something outside of his mind, and thus, an external world.
   Descartes goes on to show that the things in the external world are
   material by arguing that since God would not deceive him as to the
   ideas that are being transmitted, and that God has given him the
   "propensity" to believe that such ideas are caused by material things.
   Skeptics have responded to Descartes' proof for the external world by
   positing a brain in a vat thought experiment, in that Descartes' brain
   may be connected up to a machine which simulates all of these
   perceptions (though the vat itself would still be part of an external
   world, so this argument doesn't completely eliminate that outside the
   mind.)

Mathematical legacy

   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 .
   This appears even more astounding considering 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' rule of signs is also a commonly used method in modern
   mathematics to determine possible quantities of positive and negative
   zeros of a function.

   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°).

Writings by Descartes

     * 1618. Compendium Musicae. A treatise on music theory and the
       aesthetics of music written for Descartes' early collaborator Isaac
       Beeckman.
     * 1626–1628. Regulae ad directionem ingenii ( Rules for the Direction
       of the Mind). Incomplete. First published posthumously in 1684. The
       best critical edition, which includes an early Dutch translation,
       is edited by Giovanni Crapulli (The Hague: Martinus Nijhoff, 1966).
     * 1630–1633. Le Monde ( The World) and L'Homme (Man). Descartes'
       first systematic presentation of his natural philosophy. Man was
       first published in Latin translation in 1662; The World in 1664.
     * 1637. Discours de la méthode ( Discourse on Method). An
       introduction to the Essais, which include the Dioptrique, the
       Météores and the Géométrie.
     * 1637. La Géométrie (Geometry). Descartes' major work in
       mathematics. There is an English translation by Michael Mahoney
       (New York: Dover, 1979).
     * 1641. Meditationes de prima philosophia ( Meditations on First
       Philosophy), also known as Metaphysical Meditations. In Latin; a
       French translation, probably done without Descartes' supervision,
       was published in 1647. Includes six Objections and Replies. A
       second edition, published the following year, included an
       additional objection and reply, and a Letter to Dinet.
     * 1644. Principia philosophiae ( Principles of Philosophy). A Latin
       textbook at first intended by Descartes to replace the Aristotelian
       textbooks then used in universities. A French translation,
       Principes de philosophie by Claude Picot, under the supervision of
       Descartes, appeared in 1647 with a letter-preface to Queen
       Christina of Sweden.
     * 1647. Notae in programma (Comments on a Certain Broadsheet). A
       reply to Descartes' one-time disciple Henricus Regius.
     * 1647. The Description of the Human Body. Published posthumously.
     * 1648. Responsiones Renati Des Cartes… (Conversation with Burman).
       Notes on a Q&A session between Descartes and Frans Burman on 16
       April 1648. Rediscovered in 1895 and published for the first time
       in 1896. An annotated bilingual edition (Latin with French
       translation), edited by Jean-Marie Beyssade, was published in 1981
       (Paris: PUF).
     * 1649. Les passions de l'âme ( Passions of the Soul). Dedicated to
       Princess Elizabeth of Bohemia.
     * 1657. Correspondance. Published by Descartes' literary executor
       Claude Clerselier. The third edition, in 1667, was the most
       complete; Clerselier omitted, however, much of the material
       pertaining to mathematics.

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