René Descartes ( or ; ; Latinized:
31 March 1596 – 11 February 1650) was a French-born philosopher
, and scientist
who spent a large portion of his working life in the Dutch Republic
, initially serving the Dutch States Army
of Maurice of Nassau
, Prince of Orange
and the Stadtholder
of the United Provinces
. One of the most notable intellectual figures of the Dutch Golden Age
, Descartes is also widely regarded as one of the founders of modern philosophy
Many elements of Descartes's philosophy have precedents in late Aristotelianism
, the revived Stoicism
of the 16th century, or in earlier philosophers like Augustine
. In his natural philosophy
, he differed from the schools
on two major points: first, he rejected the splitting of corporeal substance
into matter and form; second, he rejected any appeal to final ends
, divine or natural, in explaining natural phenomena. In his theology, he insists on the absolute freedom of God's act of creation
. 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 " la|link=no|cogito, ergo sum
|label=none" ("I think, therefore I am"; french: link=no|Je pense, donc je suis), found in ''Discourse on the Method
'' (1637; in French and Latin) and ''Principles of Philosophy
'' (1644, in Latin).
Descartes has often been called the father of modern philosophy
, and is largely seen as responsible for the increased attention given to epistemology
in the 17th century.
[Bertrand Russell (2004]
''History of western philosophy''
pp. 511, 516–17
He laid the foundation for 17th-century continental rationalism
, later advocated by Spinoza
, and was later opposed by the empiricist
school of thought consisting of Hobbes
, and Hume
. In the 17th-century Dutch Republic, the rise of early modern rationalism – as a highly systematic school of philosophy in its own right for the first time in history – exerted an immense and profound influence on modern Western thought in general, with the birth of two influential rationalistic philosophical systems of Descartes (who spent most of his adult life and wrote all his major work in the United Provinces of the Netherlands) and Spinoza – namely Cartesianism
. It was the 17th-century arch-rationalists like Descartes, Spinoza and Leibniz who have given the "Age of Reason
" its name and place in history. Leibniz, Spinoza, and Descartes were all well-versed in mathematics as well as philosophy, and Descartes and Leibniz contributed greatly to science as well.
Descartes's ''Meditations on First Philosophy
'' (1641) continues to be a standard text at most university philosophy departments. Descartes's influence in mathematics is equally apparent; the Cartesian coordinate system
was named after him
. He is credited as the father of analytical geometry
, the bridge between algebra
—used in the discovery of infinitesimal calculus
. Descartes was also one of the key figures in the Scientific Revolution
thumb|Graduation registry for Descartes at the University of Poitiers
René Descartes was born in La Haye en Touraine, Province of Touraine
, on 31 March 1596.
His mother, Jeanne Brochard, died soon after giving birth to him, and so he was not expected to survive.
Descartes' father, Joachim, was a member of the Parlement of Brittany
. René lived with his grandmother and with his great-uncle. Although the Descartes family was Roman Catholic, the Poitou
region was controlled by the Protestant Huguenots
. In 1607, late because of his fragile health, he entered the Jesuit Collège Royal Henry-Le-Grand
at La Flèche
where he was introduced to mathematics and physics, including Galileo
After graduation in 1614, he studied for two years (1615–16) at the University of Poitiers
, earning a ''Baccalauréat
'' and ''Licence
'' in canon
and civil law
in accordance with his father's wishes that he should become a lawyer. From there, he moved to Paris.
In ''Discourse on the Method
'', Descartes recalls:
I entirely abandoned the study of letters. Resolving to seek no knowledge other than that of 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 to derive some profit from it.
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
[Gaukroger, Stephen. 1995. ]
Descartes: An Intellectual Biography
'. Oxford: Clarendon Press.
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). Together, they worked on free fall
, conic section
, and fluid statics
. Both believed that it was necessary to create a method that thoroughly linked mathematics and physics.
[Durandin, Guy. 1970. ''Les Principes de la Philosophie. Introduction et notes''. Paris: Librairie Philosophique J. Vrin.]
While in the service of the Catholic
Duke Maximilian of Bavaria
since 1619, Descartes was present at the Battle of the White Mountain
, in November 1620.
According to Adrien Baillet
, on the night of 10–11 November 1619 (St. Martin's Day
), while stationed in Neuburg an der Donau
, Descartes shut himself in a room with an "oven" (probably a cocklestove
) to escape the cold. While within, he had three dreams,
and believed that a divine spirit revealed to him a new philosophy. However, it is likely that what Descartes considered to be his second dream was actually an episode of exploding head syndrome
Upon exiting, he had formulated analytical geometry
and the idea of applying the mathematical method to philosophy. He concluded from these visions 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. Descartes also saw very clearly that all truths were linked with one another, so that finding a fundamental truth and proceeding with logic would open the way to all science. Descartes discovered this basic truth quite soon: his famous "I think, therefore I am
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: ''Regulae ad Directionem Ingenii'' (''Rules for the Direction of the Mind
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
[Shea, William R. 1991. ''The Magic of Numbers and Motion''. Science History Publications.]
In the fall of the same 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, Nicolas de Villiers, Sieur de Chandoux, on the principles of a supposed new philosophy, Cardinal Bérulle
urged him to write an exposition of his new philosophy in some location beyond the reach of the Inquisition.
Descartes returned to the Dutch Republic
In April 1629, he joined the University of Franeker
, studying under Adriaan Metius
, either living with a Catholic family or renting the Sjaerdemaslot
. The next year, under the name "Poitevin", he enrolled at Leiden University
to study both mathematics with Jacobus Golius
, who confronted him with Pappus's hexagon theorem
, and astronomy
with Martin Hortensius
. 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 died of scarlet fever at the age of 5.
Unlike many moralists of the time, Descartes did not deprecate the passions but rather defended them; he wept upon Francine's death in 1640. According to a recent biography by Jason Porterfield, "Descartes said that he did not believe that one must refrain from tears to prove oneself a man." 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.
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:
"Les Météores" (The Meteors), "La Dioptrique
" (Dioptrics) and ''La Géométrie
'' (''Geometry''), preceded by an introduction, his famous ''Discours de la méthode'' (''Discourse on the Method
In it, Descartes lays out four rules of thought, meant to ensure that our knowledge rests upon a firm foundation:
In ''La Géométrie'', Descartes exploited the discoveries he made with Pierre de Fermat
, having been able to do so because his paper, ''Introduction to Loci'', was published posthumously in 1679. 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, ''Meditationes de Prima Philosophia'' (''Meditations on First Philosophy''), written in Latin and thus addressed to the learned. It was followed in 1644 by ''Principia Philosophiae'' (''Principles of Philosophy
''), 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, settling in Egmond-Binnen
posits that the most influential ideas in ''Meditations on First Philosophy'' were lifted from Spanish author and Roman Catholic nun Teresa of Ávila
, who, fifty years earlier, published ''The Interior Castle
'', concerning the role of philosophical reflection in intellectual growth.
"Descartes' debt to Teresa of Ávila, or why we should work on women in the history of philosophy"
''Philosophical Studies'' 174, 2017.
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. Connected with this correspondence, in 1649 he published ''Les Passions de l'âme'' (''Passions of the Soul''), which he dedicated to the Princess. In 1647, he was awarded a pension by King Louis XIV of France
, though it was never paid.
[Descartes, René. (2009). ''Encyclopædia Britannica 2009 Deluxe Edition''. Chicago: Encyclopædia Britannica.]
A French translation of ''Principia Philosophiae'', 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.
By 1649, Descartes had become one of Europe's most famous philosophers and scientists.
That year, Queen Christina of Sweden
invited him to her court to organize a new scientific academy and tutor her in his ideas about love. She was interested in and stimulated Descartes to publish the ''Passions of the Soul
'', a work based on his correspondence with Princess Elisabeth.
Descartes accepted, and moved to Sweden in the middle of winter.
He was a guest at the house of Pierre Chanut
, living on Västerlånggatan
, less than 500 meters from Tre Kronor
. 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.
Descartes arranged to give lessons to Queen Christina after her birthday, three times a week at 5 am, in her cold and draughty castle. It soon became clear they did not like each other; she did not care for his mechanical philosophy
, nor did he share her interest in Ancient Greek
. By 15 January 1650, Descartes had seen Christina only four or five times. On 1 February, he contracted pneumonia
and died on 11 February. The cause of death was pneumonia according to Chanut, but peripneumonia
according to Christina's physician Johann van Wullen who was not allowed to bleed him. (The winter seems to have been mild, except for the second half of January which was harsh as described by Descartes himself; however, "this remark was probably intended to be as much Descartes' take on the intellectual climate as it was about the weather.")
has questioned this account, based on a letter by the Doctor van Wullen; however, Descartes had refused his treatment, and more arguments against its veracity have been raised since. In a 2009 book, German philosopher Theodor Ebert argues that Descartes was poisoned by a Catholic missionary who opposed his religious views.
As a Catholic
in a Protestant nation, he was interred in a graveyard used mainly for orphans in Adolf Fredriks kyrka
in Stockholm. His manuscripts came into the possession of Claude Clerselier
, Chanut's brother-in-law, and "a devout Catholic who has begun the process of turning Descartes into a saint by cutting, adding and publishing his letters selectively." In 1663, the Pope
placed Descartes' works on the ''Index of Prohibited Books''
. In 1666, sixteen years after his death, his remains were taken to France and buried in Saint-Étienne-du-Mont
. In 1671, Louis XIV
prohibited all the lectures in Cartesianism
. Although the National Convention
in 1792 had planned to transfer his remains to the Panthéon
, he was reburied in the Abbey of Saint-Germain-des-Prés
in 1819, missing a finger and the skull. His skull is on display in the Musée de l'Homme
Initially, Descartes arrives at only a single first principle: I think. Thought cannot be separated from me, therefore, I exist (''Discourse on the Method'' and ''Principles of Philosophy''). Most notably, this is known as ''cogito ergo sum'' (English: "I think, therefore I am"). Descartes concluded, if he doubted, then something or someone must be doing the doubting; therefore, the very fact that he doubted proved his existence. "The simple meaning of the phrase is that if one is skeptical of existence, that is in and of itself proof that he does exist." These two first principles—I think and I exist—were later confirmed by Descartes' clear and distinct perception (delineated in his ''Third Meditation''
): that I clearly and distinctly perceive these two principles, Descartes reasoned, ensures their indubitability.
Descartes concludes that he can be certain that he exists because he thinks. But in what form? He perceives his body through the use of the senses; however, these have previously been unreliable. So Descartes determines that the only indubitable knowledge is that he is a ''thinking thing''. Thinking is what he does, and his power must come from his essence. 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 the person is immediately conscious
. He gave reasons for thinking that waking thoughts are distinguishable from dreams
, and that one's mind cannot have been "hijacked" by an evil demon
placing an illusory external world before one's senses.
In this manner, Descartes proceeds to construct a system of knowledge, discarding perception
as unreliable and, instead, admitting only deduction
as a method.
Descartes, influenced by the automaton
s on display throughout the city of Paris, began to investigate the connection between the mind and body, and how the two interact. His main influences for dualism
. The theory on the dualism of mind and body is Descartes' signature doctrine and permeates other theories he advanced. Known as Cartesian dualism
(or mind–body dualism), his theory on the separation between the mind and the body went on to influence subsequent Western philosophies. In ''Meditations on First Philosophy
'', Descartes attempted to demonstrate the existence of God
and the distinction between the human soul and the body. Humans are a union of mind and body; thus Descartes's dualism embraced the idea that mind and body are distinct but closely joined. While many contemporary readers of Descartes found the distinction between mind and body difficult to grasp, he thought it was entirely straightforward. Descartes employed the concept of ''modes'', which are the ways in which substances exist. In ''Principles of Philosophy
'', Descartes explained, "we can clearly perceive a substance apart from the mode which we say differs from it, whereas we cannot, conversely, understand the mode apart from the substance". To perceive a mode apart from its substance requires an intellectual abstraction,
which Descartes explained as follows:
The intellectual abstraction consists in my turning my thought away from one part of the contents of this richer idea the better to apply it to the other part with greater attention. Thus, when I consider a shape without thinking of the substance or the extension whose shape it is, I make a mental abstraction.
According to Descartes, two substances are really distinct when each of them can exist apart from the other. Thus, Descartes reasoned that God is distinct from humans, and the body and mind of a human are also distinct from one another. He argued that the great differences between body (an extended thing) and mind (an un-extended, immaterial thing) make the two ontologically distinct. But that the mind was utterly indivisible: because "when I consider the mind, or myself in so far as I am merely a thinking thing, I am unable to distinguish any part within myself; I understand myself to be something quite single and complete."
In ''Meditations'', Descartes invokes his causal adequacy principle
to support his trademark argument
for the existence of God, quoting Lucretius in defence: ''"Ex nihilo nihil fit"'', meaning "Nothing comes from nothing
). Granted, neither Descartes nor Lucretius originated the philosophical claim, appearing as it does in the classical metaphysics of Plato
Moreover, in ''Meditations'', Descartes discusses a piece of wax
and exposes the single most characteristic doctrine of Cartesian dualism: that the universe contained two radically different kinds of substances—the mind or soul defined as thinking
, and the body defined as matter and unthinking. The Aristotelian philosophy
of Descartes' days held that the universe was inherently purposeful or teleological. Everything that happened, be it the motion of the star
s or the growth of a tree
, was supposedly explainable by a certain purpose, goal or end that worked its way out within nature. Aristotle called this the "final cause," and these final causes were indispensable for explaining the ways nature operated. Descartes' theory of dualism supports the distinction between traditional Aristotelian science and the new science of Kepler
and Galileo, which denied the role of a divine power and "final causes" in its attempts to explain nature. Descartes' dualism provided the philosophical rationale for the latter by expelling the final cause from the physical universe (or ''res extensa'') in favor of the mind (or ''res cogitans''). Therefore, while Cartesian dualism paved the way for modern physics
, it also held the door open for religious beliefs about the immortality of the soul
Descartes' dualism of mind and matter implied a concept of human beings. A human was, according to Descartes, a composite entity of mind and body. Descartes gave priority to the mind and argued that the mind could exist without the body, but the body could not exist without the mind. In ''Meditations'', Descartes even argues that while the mind is a substance, the body is composed only of "accidents". But he did argue that mind and body are closely joined:
Nature also teaches me, by the sensations of pain, hunger, thirst and so on, that I am not merely present in my body as a pilot in his ship, but that I am very closely joined and, as it were, intermingled with it, so that I and the body form a unit. If this were not so, I, who am nothing but a thinking thing, would not feel pain when the body was hurt, but would perceive the damage purely by the intellect, just as a sailor perceives by sight if anything in his ship is broken.
Descartes' discussion on embodiment raised one of the most perplexing problems of his dualism philosophy: What exactly is the relationship of union between the mind and the body of a person?
Therefore, Cartesian dualism set the agenda for philosophical discussion of the mind–body problem
for many years after Descartes' death. Descartes was also a rationalist
and believed in the power of innate ideas
Descartes argued the theory of innate knowledge
and that all humans were born with knowledge through the higher power of God. It was this theory of innate knowledge that later led philosopher John Locke
(1632–1704) to combat the theory of empiricism
, which held that all knowledge is acquired through experience.
Physiology and psychology
In ''The Passions of the Soul'', written between 1645 and 1646, Descartes discussed the common contemporary belief that the human body contained animal spirits. These animal spirits were believed to be light and roaming fluids circulating rapidly around the nervous system between the brain and the muscles, and served as a metaphor for feelings, like being in high or bad spirit. These animal spirits were believed to affect the human soul, or passions of the soul. Descartes distinguished six basic passions: wonder, love, hatred, desire, joy and sadness. All of these passions, he argued, represented different combinations of the original spirit, and influenced the soul to will or want certain actions. He argued, for example, that fear is a passion that moves the soul to generate a response in the body. In line with his dualist teachings on the separation between the soul and the body, he hypothesized that some part of the brain served as a connector between the soul and the body and singled out the pineal gland
as connector. Descartes argued that signals passed from the ear and the eye to the pineal gland, through animal spirits. Thus different motions in the gland cause various animal spirits. He argued that these motions in the pineal gland are based on God's will and that humans are supposed to want and like things that are useful to them. But he also argued that the animal spirits that moved around the body could distort the commands from the pineal gland, thus humans had to learn how to control their passions.
Descartes advanced a theory on automatic bodily reactions to external events, which influenced 19th-century reflex
theory. He argued that external motions, such as touch and sound, reach the endings of the nerves and affect the animal spirits. Heat from fire affects a spot on the skin and sets in motion a chain of reactions, with the animal spirits reaching the brain through the central nervous system, and in turn, animal spirits are sent back to the muscles to move the hand away from the fire.
Through this chain of reactions, the automatic reactions of the body do not require a thought process.
Above all, he was among the first scientists who believed that the soul should be subject to scientific investigation. He challenged the views of his contemporaries that the soul was divine
, thus religious authorities regarded his books as dangerous. Descartes' writings went on to form the basis for theories on emotion
s and how cognitive
evaluations were translated into affective processes. Descartes believed that the brain resembled a working machine and unlike many of his contemporaries, he believed that mathematics and mechanics could explain the most complicated processes of the mind. In the 20th century, Alan Turing
advanced computer science
based on mathematical biology
as inspired by Descartes. His theories on reflexes also served as the foundation for advanced physiological theories
, more than 200 years after his death. The physiologist Ivan Pavlov
was a great admirer of Descartes.
For Descartes, ethics
was a science, the highest and most perfect of them. Like the rest of the sciences, ethics had its roots in metaphysics.
In this way, he argues for the existence of God, investigates the place of man in nature, formulates the theory of mind–body dualism, and defends free will
. However, as he was a convinced rationalist, Descartes clearly states that reason is sufficient in the search for the goods that we should seek, and virtue
consists in the correct reasoning that should guide our actions. Nevertheless, the quality of this reasoning depends on knowledge, because a well-informed mind will be more capable of making good choices
, and it also depends on mental condition. For this reason, he said that a complete moral philosophy should include the study of the body. He discussed this subject in the correspondence with Princess Elisabeth of Bohemia
, and as a result wrote his work ''The Passions of the Soul'', that contains a study of the psychosomatic
processes and reactions in man, with an emphasis on emotions or passions.
[Blom, John J., Descartes. His moral philosophy and psychology. New York University Press. 1978. ]
His works about human passion and emotion would be the basis for the philosophy of his followers (see Cartesianism
), and would have a lasting impact on ideas concerning what literature and art should be, specifically how it should invoke emotion.
Humans should seek the sovereign good
that Descartes, following Zeno
, identifies with virtue, as this produces a solid blessedness
. For Epicurus
, the sovereign good was pleasure, and Descartes says that, in fact, this is not in contradiction with Zeno's teaching, because virtue produces a spiritual pleasure, that is better than bodily pleasure. Regarding Aristotle
's opinion that happiness depends on the goods of fortune, Descartes does not deny that this good contributes to happiness but remarks that they are in great proportion outside one's own control, whereas one's mind is under one's complete control.
The moral writings of Descartes came at the last part of his life, but earlier, in his ''Discourse on the Method'', he adopted three maxims to be able to act while he put all his ideas into doubt. This is known as his "Provisional Morals"
In the third and fifth ''Meditation'', Descartes offers ontological proof
of a benevolent God (through both the ontological argument and trademark argument
). Because God is benevolent, Descartes 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. From this supposition, however, Descartes finally establishes the possibility of acquiring knowledge about the world based on deduction ''and'' perception. Regarding epistemology
, therefore, Descartes 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. Descartes, however, was very much aware that experimentation was necessary to verify and validate theories.
In his ''Meditations on First Philosophy'', Descartes sets forth two proofs for God's existence. One of these is founded on the possibility of thinking the "idea of a being that is supremely perfect and infinite," and suggests that "of all the ideas that are in me, the idea that I have of God is the most true, the most clear and distinct." Descartes considered himself to be a devout Catholic,
and one of the purposes of the ''Meditations'' was to defend the Catholic faith. His attempt to ground theological beliefs on reason encountered intense opposition in his time. Pascal
regarded Descartes' views as a rationalist and mechanist, and accused him of deism
: "I cannot forgive Descartes; in all his philosophy, Descartes did his best to dispense with God. But Descartes could not avoid prodding God to set the world in motion with a snap of his lordly fingers; after that, he had no more use for God," while a powerful contemporary, Martin Schoock
, accused him of atheist
beliefs, though Descartes had provided an explicit critique of atheism in his ''Meditations''. The Catholic Church prohibited his books in 1663.
Descartes also wrote a response to external world skepticism
. Through this method of scepticism, he does not doubt for the sake of doubting but to achieve concrete and reliable information. In other words, certainty. He argues that sensory perception
s 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 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. Descartes also believes a substance is something that does not need any assistance to function or exist. Descartes further explains how only God can be a true "substance". But minds are substances, meaning they need only God for it to function. The mind is a thinking substance. The means for a thinking substance stem from ideas.
Descartes steered clear of theological questions, restricting his attention to showing that there is no incompatibility between his metaphysics and theological orthodoxy. He avoided trying to demonstrate theological dogmas metaphysically. When challenged that he had not established the immortality of the soul merely in showing that the soul and the body are distinct substances, for example, he replied, "I do not take it upon myself to try to use the power of human reason to settle any of those matters which depend on the free will of God."
Descartes is often regarded as the first thinker to emphasize the use of reason to develop the natural science
s. For him, philosophy was a thinking system that embodied all knowledge, as he related in a letter to a French translator:
In his ''Discourse on the Method'', 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 hyperbolical/metaphysical doubt, also sometimes referred to as methodological skepticism
: he rejects any ideas that can be doubted and then re-establishes them in order to acquire a firm foundation for genuine knowledge. Descartes built his ideas from scratch. He relates this to architecture: the top soil is taken away to create a new building or structure. Descartes calls his doubt the soil and new knowledge the buildings. To Descartes, Aristotle's foundationalism is incomplete and his method of doubt enhances foundationalism.
Descartes denied that animals had reason or intelligence. He argued that animals did not lack sensations or perceptions, but these could be explained mechanistically. Whereas humans had a soul, or mind, and were able to feel pain
, animals by virtue of not having a soul could not feel pain or anxiety. If animals showed signs of distress then this was to protect the body from damage, but the innate state needed for them to suffer
was absent. Although Descartes' views were not universally accepted, they became prominent in Europe and North America, allowing humans to treat animals with impunity. The view that animals were quite separate from humanity and merely machine
s allowed for the maltreatment of animals
, and was sanctioned in law and societal norms until the middle of the 19th century. The publications of Charles Darwin
would eventually erode the Cartesian view of animals. Darwin argued that the continuity between humans and other species opened the possibilities that animals did not have dissimilar properties to suffer.
Emancipation from Church doctrine
Descartes has often been dubbed the father of modern Western philosophy
, the thinker whose approach has profoundly changed the course of Western philosophy and set the basis for modernity
The first two of his ''Meditations on First Philosophy'', those that formulate the famous methodic doubt
, represent the portion of Descartes's writings that most influenced modern thinking. It has been argued that Descartes himself did not realize the extent of this revolutionary move. In shifting the debate from "what is true" to "of what can I be certain?", Descartes arguably shifted the authoritative guarantor of truth from God to humanity (even though Descartes himself claimed he received his visions from God)—while the traditional concept of "truth" implies an external authority, "certainty" instead relies on the judgment of the individual.
In an anthropocentric
revolution, the human being is now raised to the level of a subject, an agent, an emancipated
being equipped with autonomous reason. This was a revolutionary step that established the basis of modernity, the repercussions of which are still being felt: the emancipation of humanity from Christian revelation
al truth and Church doctrine
; humanity making its own law and taking its own stand.
[Martin Heidegger 938(2002) ''The Age of the World Picture'' quotation: ] [Ingraffia, Brian D. (1995]
''Postmodern theory and biblical theology: vanquishing God's shadow''
In modernity, the guarantor of truth is not God anymore but human beings, each of whom is a "self-conscious shaper and guarantor" of their own reality.
In that way, each person is turned into a reasoning adult, a subject and agent,
[Lovitt, Tom (1977) introduction to Martin Heidegger's ''The question concerning technology, and other essays'', pp. xxv–xxvi]
as opposed to a child obedient to God. This change in perspective was characteristic of the shift from the Christian medieval period to the modern period, a shift that had been anticipated in other fields, and which was now being formulated in the field of philosophy by Descartes.
This anthropocentric perspective of Descartes's work, establishing human reason as autonomous, provided the basis for the Enlightenment
's emancipation from God and the Church. According to Martin Heidegger, the perspective of Descartes's work also provided the basis for all subsequent anthropology
[Heidegger 938(2002), p. 75 quotation: ]
Descartes's philosophical revolution is sometimes said to have sparked modern anthropocentrism
One of Descartes's most enduring legacies was his development of Cartesian or analytic geometry
, which uses algebra to describe geometry. Descartes "invented the convention of representing unknowns in equations by ''x'', ''y'', and ''z'', and knowns by ''a'', ''b'', and ''c''". He also "pioneered the standard notation" that uses superscripts
to show the powers or exponents; for example, the 2 used in x2
to indicate x squared. He was first to assign a fundamental place for algebra in the system of knowledge, using it as a method to automate or mechanize reasoning, particularly about abstract, unknown quantities. European mathematicians had previously viewed geometry as a more fundamental form of mathematics, serving as the foundation of algebra. Algebraic rules were given geometric proofs by mathematicians such as Pacioli
. Equations of degree
higher than the third were regarded as unreal, because a three-dimensional form, such as a cube, occupied the largest dimension of reality. Descartes professed that the abstract quantity ''a2
'' could represent length as well as an area. This was in opposition to the teachings of mathematicians such as François Viète
, who insisted that a second power must represent an area. Although Descartes did not pursue the subject, he preceded Gottfried Wilhelm Leibniz
in envisioning a more general science of algebra or "universal mathematics," as a precursor to symbolic logic
, that could encompass logical principles and methods symbolically, and mechanize general reasoning.
Descartes's work provided the basis for the calculus
developed by Newton
and Leibniz, who applied infinitesimal calculus to the tangent line problem
, thus permitting the evolution of that branch of modern mathematics. His rule of signs
is also a commonly used method to determine the number of positive and negative roots of a polynomial.
The beginning to Descartes's interest in physics is accredited to the amateur scientist and mathematician Isaac Beeckman
, who was at the forefront of a new school of thought known as mechanical philosophy
. With this foundation of reasoning, Descartes formulated many of his theories on mechanical and geometric physics
Descartes discovered an early form of the law of conservation of momentum
(a measure of the motion of an object), and envisioned it as pertaining to motion in a straight line, as opposed to perfect circular motion, as Galileo had envisioned it.
[ He outlined his views on the universe in his ''Principles of Philosophy'', where he describes his three laws of motion. (Newton's own laws of motion would later be modeled on Descartes' exposition.] [)
Descartes also made contributions to the field of optics. He showed by using geometric construction and the law of refraction (also known as Descartes's law, or more commonly Snell's law outside France) that the angular radius of a rainbow is 42 degrees (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°). He also independently discovered the law of reflection, and his essay on optics was the first published mention of this law.
Influence on Newton's mathematics
Current popular opinion holds that Descartes had the most influence of anyone on the young Newton, and this is arguably one of his most important contributions. Decartes's influence extended not directly from his original French edition of ''La Géométrie'', however, but rather from Frans van Schooten's expanded second Latin edition of the work. Newton continued Descartes's work on cubic equations, which will free the subject from fetters of the Greek perspectives. The most important concept was his very modern treatment of single variables.
In commercial terms, ''Discourse'' appeared during Descartes's lifetime in a single edition of 500 copies, 200 of which were set aside for the author. Sharing a similar fate was the only French edition of ''Meditations'', which had not managed to sell out by the time of Descartes's death. A concomitant Latin edition of the latter was, however, eagerly sought out by Europe's scholarly community and proved a commercial success for Descartes.
Although Descartes was well known in academic circles towards the end of his life, the teaching of his works in schools was controversial. Henri de Roy (Henricus Regius, 1598–1679), Professor of Medicine at the University of Utrecht, was condemned by the Rector of the University, Gijsbert Voet (Voetius), for teaching Descartes's physics.
* Cartesian plane
* Cartesian product
* Cartesian product of graphs
* Cartesian theater
* Cartesian tree
* Descartes number
* Descartes' rule of signs
* Descartes's theorem (4 tangent circles)
* Descartes' theorem on total angular defect
* Folium of Descartes
* Bucket argument
* Cartesian circle
* Cartesian doubt
* 3587 Descartes, asteroid
* Descartes crater and Highlands on the Moon (Apollo 16 landing site)
* Cartesian materialism (not a view that was held by or formulated by Descartes)
* Paris Descartes University
A treatise on music theory and the aesthetics of music, which Descartes dedicated to early collaborator Isaac Beeckman (written in 1618, first published—posthumously—in 1650).
* 1626–1628. ''Regulae ad directionem ingenii'' (''Rules for the Direction of the Mind''). Incomplete. First published posthumously in Dutch translation in 1684 and in the original Latin at Amsterdam in 1701 (''R. Des-Cartes Opuscula Posthuma Physica et Mathematica''). The best critical edition, which includes the Dutch translation of 1684, is edited by Giovanni Crapulli (The Hague: Martinus Nijhoff, 1966).
* c. 1630. ''De solidorum elementis''. Concerns the classification of Platonic solids and three-dimensional figurate numbers. Said by some scholars to prefigure Euler's polyhedral formula. Unpublished; discovered in Descartes' estate in Stockholm 1650, soaked for three days in the Seine in a shipwreck while being shipped back to Paris, copied in 1676 by Leibniz, and lost. Leibniz's copy, also lost, was rediscovered circa 1860 in Hannover.
* 1630–1631. ''La recherche de la vérité par la lumière naturelle'' (''The Search for Truth'') unfinished dialogue published in 1701.
* 1630–1633. ''Le Monde'' (''The World'') and ''L'Homme'' (''Man''). Descartes's first systematic presentation of his natural philosophy. ''Man'' was published posthumously in Latin translation in 1662; and ''The World'' posthumously in 1664.
* 1637. ''Discours de la méthode'' (''Discourse on the Method''). An introduction to the ''Essais'', which include the ''Dioptrique'', the ''Météores'' and the ''Géométrie''.
* 1637. ''La Géométrie'' (''Geometry''). Descartes's 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 second edition, published the following year, included an additional objection and reply, and a ''Letter to Dinet''. A French translation by the Duke of Luynes, probably done without Descartes's supervision, was published in 1647. Includes six Objections and Replies.
* 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 Princess Elisabeth of Bohemia.
* 1647. ''Notae in programma'' (''Comments on a Certain Broadsheet''). A reply to Descartes's one-time disciple Henricus Regius.
* 1648. ''La description du corps humain'' (''The Description of the Human Body''). Published posthumously by Clerselier in 1667.
* 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 Elisabeth of the Palatinate.
* 1657. ''Correspondance'' (three volumes: 1657, 1659, 1667). Published by Descartes's literary executor Claude Clerselier. The third edition, in 1667, was the most complete; Clerselier omitted, however, much of the material pertaining to mathematics.
In January 2010, a previously unknown letter from Descartes, dated 27 May 1641, was found by the Dutch philosopher Erik-Jan Bos when browsing through Google. Bos found the letter mentioned in a summary of autographs kept by Haverford College in Haverford, Pennsylvania. The college was unaware that the letter had never been published. This was the third letter by Descartes found in the last 25 years.
File:Handwritten letter by Descartes December 1638.jpg|Handwritten letter by Descartes, December 1638
File:René Descartes 1644 Principia philosophiae.jpg|''Principia philosophiae'', 1644
* ''Oeuvres de Descartes'' edited by Charles Adam and Paul Tannery, Paris: Léopold Cerf, 1897–1913, 13 volumes; new revised edition, Paris: Vrin-CNRS, 1964–1974, 11 volumes (the first 5 volumes contains the correspondence). his edition is traditionally cited with the initials ''AT'' (for Adam and Tannery) followed by a volume number in Roman numerals; thus ''AT'' VII refers to ''Oeuvres de Descartes'' volume 7.* ''Étude du bon sens, La recherche de la vérité et autres écrits de jeunesse (1616–1631)'' edited by Vincent Carraud and Gilles Olivo, Paris: PUF, 2013.
* Descartes, ''Œuvres complètes'', new edition by Jean-Marie Beyssade and Denis Kambouchner, Paris: Gallimard, published volumes:
** I: ''Premiers écrits. Règles pour la direction de l'esprit'', 2016.
** III: ''Discours de la Méthode et Essais'', 2009.
** VIII.1: ''Correspondance, 1'' edited by Jean-Robert Armogathe, 2013.
** VIII.2: ''Correspondance, 2'' edited by Jean-Robert Armogathe, 2013.
* ''René Descartes. Opere 1637–1649'', Milano, Bompiani, 2009, pp. 2531. Edizione integrale (di prime edizioni) e traduzione italiana a fronte, a cura di G. Belgioioso con la collaborazione di I. Agostini, M. Marrone, M. Savini .
* ''René Descartes. Opere 1650–2009'', Milano, Bompiani, 2009, pp. 1723. Edizione integrale delle opere postume e traduzione italiana a fronte, a cura di G. Belgioioso con la collaborazione di I. Agostini, M. Marrone, M. Savini .
* ''René Descartes. Tutte le lettere 1619–1650'', Milano, Bompiani, 2009 IIa ed., pp. 3104. Nuova edizione integrale dell'epistolario cartesiano con traduzione italiana a fronte, a cura di G. Belgioioso con la collaborazione di I. Agostini, M. Marrone, F.A. Meschini, M. Savini e J.-R. Armogathe .
* ''René Descartes, Isaac Beeckman, Marin Mersenne. Lettere 1619–1648'', Milano, Bompiani, 2015 pp. 1696. Edizione integrale con traduzione italiana a fronte, a cura di Giulia Beglioioso e Jean Robert-Armogathe .
Early editions of specific works
''Discours de la methode''
''Renati Des-Cartes Principia philosophiæ''
''Le monde de Mr. Descartes ou le traité de la lumiere''
''Meditationes de prima philosophia''
Collected English translations
* 1955. ''The Philosophical Works'', E.S. Haldane and G.R.T. Ross, trans. Dover Publications. This work is traditionally cited with the initials ''HR'' (for Haldane and Ross) followed by a volume number in Roman numerals; thus ''HR'' II refers to volume 2 of this edition.
* 1988. ''The Philosophical Writings of Descartes'' in 3 vols. Cottingham, J., Stoothoff, R., Kenny, A., and Murdoch, D., trans. Cambridge University Press. This work is traditionally cited with the initials ''CSM'' (for Cottingham, Stoothoff, and Murdoch) or ''CSMK'' (for Cottingham, Stoothoff, Murdoch, and Kenny) followed by a volume number in Roman numeral; thus ''CSM'' II refers to volume 2 of this edition.
* 1998. ''René Descartes: The World and Other Writings.'' Translated and edited by Stephen Gaukroger. Cambridge University Press. (This consists mainly of scientific writings, on physics, biology, astronomy, optics, etc., which were very influential in the 17th and 18th centuries, but which are routinely omitted or much abridged in modern collections of Descartes's ''philosophical'' works.)
Translation of single works
''Regulae ad directionem ingenii. Rules for the Direction of the Natural Intelligence. A Bilingual Edition of the Cartesian Treatise on Method''
ed. & trans. G. Heffernan (Amsterdam/Atlanta: Rodopi, 1998).
tr. by Michael S. Mahoney.
* 1633. ''Treatise of Man'', tr. by T. S. Hall. Cambridge, MA: Harvard University Press, 1972.
* 1637. ''Discourse on the Method, Optics, Geometry and Meteorology'', trans. P. J. Olscamp, Revised edition (Indianapolis: Hackett, 2001).
''The Geometry of René Descartes''
trans. D. E. Smith & M. L. Latham (Chicago: Open Court, 1925).
* 1641. ''Meditations on First Philosophy'', tr. by J. Cottingham, Cambridge: Cambridge University Press, 1996. Latin original. Alternative English title: ''Metaphysical Meditations''. Includes six ''Objections and Replies''. A second edition published the following year, includes an additional ''Objection and Reply'' and a ''Letter to Dinet''
HTML Online Latin-French-English Edition
''Principles of Philosophy''
trans. V. R. Miller & R. P. Miller: (Dordrecht/Boston/London: Kluwer Academic Publishers, 1982).
* 1648. ''Descartes' Conversation with Burman'', tr. by J. Cottingham, Oxford: Clarendon Press, 1989.
''Passions of the Soul''
trans. S. H. Voss (Indianapolis: Hackett, 1989). Dedicated to Elisabeth of the Palatinate.
* 1619–1648. ''René Descartes, Isaac Beeckman, Marin Mersenne. Lettere 1619–1648'', ed. by Giulia Beglioioso and Jean Robert-Armogathe, Milano, Bompiani, 2015 pp. 1696.
* ; (2009) Third Edition, edited with a new introduction by James McGilvray, Cambridge University Press,
* Farrell, John. "Demons of Descartes and Hobbes." ''Paranoia and Modernity: Cervantes to Rousseau'' (Cornell UP, 2006), chapter 7.
* Gillespie, A. (2006)
Descartes' demon: A dialogical analysis of 'Meditations on First Philosophy.'
Theory & Psychology, 16, 761–781.
* Heidegger, Martin 938(2002) ''The Age of the World Picture'' i
''Off the beaten track''
* Monnoyeur, Françoise (November 2017), ''Matière et espace dans le système cartésien'', Paris, Harmattan, 266 pages. .
* Moreno Romo, Juan Carlos, ''Vindicación del cartesianismo radical'', Anthropos, Barcelona, 2010.
* Moreno Romo, Juan Carlos (Coord.), ''Descartes vivo. Ejercicios de hermenéutica cartesiana'', Anthropos, Barcelona, 2007
* Negri, Antonio (2007) ''The Political Descartes'', Verso.
* Sasaki Chikara (2003)
''Descartes's Mathematical Thought''
(Boston Studies in the Philosophy of Science, 237.) xiv + 496 pp., bibl., indexes. Dordrecht/Boston/London: Kluwer Academic Publishers.
* Serfati, Michel, 2005, "Géometrie" in Ivor Grattan-Guinness, ed., ''Landmark Writings in Western Mathematics''. Elsevier: 1–22.
* Watson, Richard A. (2007). Cogito, Ergo Sum: a life of René Descartes. David R Godine. 2002, reprint 2007. . Was chosen by the New York Public library as one of "25 Books to Remember from 2002"
The Correspondence of René Descartes
* ttp://digitalcommons.unl.edu/modlangfrench/20/ René Descartes (1596–1650)Published in ''Encyclopedia of Rhetoric and Composition'' (1996)
A site containing Descartes's main works, including correspondence, slightly modified for easier reading
Descartes Philosophical Writings tr. by Norman Kemp Smith
Studies in the Cartesian philosophy (1902) by Norman Kemp Smith
The Philosophical Works Of Descartes Volume II (1934)
Centro Interdipartimentale di Studi su Descartes e il Seicento
* Livre Premier, ''La Géométrie'', online and analyzed by A. Warusfel
small>lick "à télécharger" for English analysis/small>
''Bibliografia cartesiana/Bibliographie cartésienne on-line (1997–2012)''
''Stanford Encyclopedia of Philosophy''
Life and works
Theory of Ideas
''Internet Encyclopedia of Philosophy''
Descartes: Mind-Body Distinction
Descartes: Scientific Method
Bernard Williams interviewed about Descartes on ''Men of ideas''
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