René Descartes 1596–1650
French philosopher and mathematician.
Descartes is considered the father of modern philosophy and one of the seminal figures of French thought. In his philosophical program, as presented in such important works as Discourse on Method and Meditations on First Philosophy, he "brought together," as Wilhelm Windelband wrote, "the scientific movement of his time to establish rationalism anew, by filling the scholastic system of conceptions with the rich content of Galilean research." Descartes argued that philosophy must be based on a clear, rational method of inquiry. In order to establish a firm basis for this method, he subjected popularly-held assumptions concerning the nature of the self and the universe to a process of rigorous doubt. Descartes effectively reduced verifiable reality to the thinking self, though he eventually accepted the objective reality of the external world and the existence of God. Critics affirm that the most significant result of Descartes' methodological skepticism was his radical separation of the thinking subject from the physical world, which he viewed in purely scientific, mechanistic terms, suggesting the modern metaphor of the world conceived as an intricate machine.
Descartes was born in 1596 at La Haye in Touraine. His family belonged to the noblesse de robe, or juridical nobility, as attested by his father's position as councilor of the parlement of Rennes in Brittany. Like his mother, who died of a lung infection a few days after his birth, Descartes suffered from a delicate constitution, and his health was a subject of great concern for his doctors. Nonetheless, in 1604 he was sent to the Jesuit college of La Flèche in Anjou, where he received a largely classical education, but also familiarized himself with new discoveries in optics and astronomy. After graduating from La Flèche in 1612, he studied law at the University of Poitiers until 1616, though he appears never to have practiced. Weary of studying, Descartes finally decided on a military career and served under the banners of Maurice of Nassau and the German emperor Ferdinand during the early phases of the Thirty Years War. During 1618–19 at Breda, Holland,
Descartes became acquainted with the famous mathematician Isaac Beeckman, who encouraged him to return to the study of science and mathematics.
In April, 1619, Descartes began travelling, settling in Neuberg, Germany, where he secluded himself "dans un poêle" ["in a heated room"] for the winter. On November 10, 1619, Descartes experienced a series of extraordinary dreams that led him to believe that he was destined to found a universal science based on mathematics. During the next few years Descartes continued travelling in Europe. He returned to France in 1622, eventually establishing himself in Paris, where he continued to refine his philosophy in the company of mathematicians and scientists. In 1628 Descartes publicly presented his philosophical ideas in a confrontation with the chemist Chandoux, who upheld a probabilistic view of science. Demonstrating to the audience through brilliant argumentation that any philosophical system not grounded in certainty would inevitably fail, Descartes was taken aside after the lecture by Cardinal de Bérulle, who urged him to fully elaborate on his method, explaining that it was God's will for him to do so. Shortly afterward Descartes completed his first substantial work, Regulae ad directionem ingenii (1701; Rules for the Direction of the Mind), explicating the methodological foundations of the new system.
At the beginning of 1629 Descartes moved to Holland, where he was able to work in an atmosphere of tranquility and intellectual freedom. In 1633 Descartes completed Le monde de M. Descartes, ou le traité de la lumière (1644; The World), in which he supported the Copernican theory of the earth's movement around the sun. However, he suppressed publication of this work after hearing from his friend Marin Marsenne of Galileo's condemnation by the Roman Catholic church for upholding the same thesis. Four years later, Descartes published Discours de la méthode de bien conduire sa raison et chercher la vérité dans les sciences; plus la dioptrique; les météores; et la géométrie, qui sont des essais de cette méthode (1637; Discourse on the Method of Properly Guiding the Reason in the Search for Truth in the Sciences; also the Dioptric, the Meteors and the Geometry, which are Essays in This Method). The four-part treatise defined the principles of modern scientific method and applied them to matters of current academic interest. Written in French in order to reach a wider audience, the work caused a critical uproar and was immediately challenged by a number of prominent mathematicians. The years 1641 and 1642 marked the appearance of two editions of the Meditations: Meditationes de prima philosophia in qua Dei existentia et animae immortalitas demonstratur (1641; "Meditations on First Philosophy, in which the Existence of God and the Immortality of the Soul are Demonstrated") and Meditationes de prima philosophia, in quibus Dei existentia et animae humanae a corpore distinctio demonstrantur (1641–42; Meditations on First Philosophy, in which the Existence of God and the Distinction between Mind and Body are Demonstrated), a comprehensive exposition of his epistemological and metaphysical theories. The work did much to augment Descartes' influence in Europe's intellectual circles. However, many of Descartes' positions were attacked by such notable scholars as Pierre Gassendi and Gysbertus Voetius, president of the University of Utrecht, who accused the author of atheism. Throughout the controversy, Descartes was supported by his many friends and admirers, including the refugee Princess Elizabeth of the Palatinate, to whom Descartes dedicated the Principia philosophia (1644; Principles of Philosophy), a four-part treatise that provided further explanation of the principal ideas of the Meditations. Descartes visited Paris in 1647, where he met Blaise Pascal and attended court, securing the promise of a pension from the crown. However, the rebellion of the Fronde in 1648 promptly rendered the promised stipend unavailable, and Descartes again returned to Holland. The following year Queen Christina of Sweden, who decided to found an academy of scholars, requested Descartes to come to Sweden and instruct her in philosophy. After overseeing the publication of Traité des passions de l'âme (1649; The Passions of the Soul), which sought to explain psychological events in mechanistic terms, Descartes left Amsterdam on September 1, 1649, and reached Stockholm a month later. Descartes was required to tutor the queen in philosophy at five o'clock each morning, a schedule he found extremely taxing. Returning to his lodging one bitter January morning in 1650, he caught pneumonia and died within a fortnight.
During the seventeenth century, Descartes was as famous for his scientific treatises as he was for his philosophical works. However, he is known today primarily for the Discourse on Method and the Meditations, which are numbered among the principal works of modern philosophy. The Discourse on Method amplified Descartes' projects for a universal methodology adumbrated in his Rules for the Direction of the Mind. The Discourse on Method is actually an extended preface to a much larger treatise comprising three separate works—Dioptrics, Meteors, and Geometry, all of which are technical discussions of scientific subjects.
The Discourse itself is divided into six chapters. The first three are primarily autobiographical, touching on Descartes' early education as well as the three dreams of November 10, 1619. Chapter four is concerned with traditional metaphysical questions about the nature of reality and contains the formula "cogito, ergo sum" ("I think, therefore I am"). The fifth chapter investigates the subjects of physics and biology, while the final chapter serves as a general conclusion. The six-part Discourse is generally upheld as an indispensable introduction to the Cartesian system. Commentators agree that the cornerstone of the work is Descartes' presentation, in Chapter Two, of the four methodological principles that establish the frame for his scientific method. Here Descartes demonstrates that useful knowledge must be founded on clear and distinct judgments which should be as irrefutable as mathematical formulae based on pure intuition and deductive reasoning.
The second edition of the Meditations of First Philosophy appeared in 1642 with a compendium of "objections" by such notable thinkers as Thomas Hobbes, Antoine Arnauld, and Pierre Gassendi. Whereas Descartes' previous works were essentially theoretical discussions on methodology, the Meditations address specific philosophical issues: skepticism, the nature of God, the metaphysical foundation of truth, and knowledge of the physical world. The work is divided into six separate Meditations, each of which focuses on a particular problem. The First Meditation invokes Descartes' principle of methodological doubt, which he saw as indispensable to creating a positive foundation for knowledge. Beginning with the assumption that all knowledge derives from sensory perception or rational intuition, Descartes purports that sensory perception is questionable. He demonstrates, for example, that in our dreams we perceive objects as clearly as when we are awake. On the other hand, purely intuitive ideas such as those pertaining to mathematics would appear to be irrefutably true, yet Descartes maintains that their relation to objective reality cannot be verified through reason alone. The Second Meditation elaborates on the relation of the thinking subject to objective reality. Descartes maintains that while sensory perceptions and pure intuitions are possibly illusory, the thinking subject cannot be doubted because the "I" accompanies every thought. Therefore, existence must be seen as a predicate of thought, as expressed in the formula "I think, therefore I am." Descartes defines man as a thinking being whose mental operations are separate and distinct from the existence of the external world. In the Third Meditation Descartes attempts to establish formal proof of the existence of God. He reasons that as God is an infinitely perfect being and is not a deceiver, there is no reason to doubt that clear and distinct perceptions correspond to objective reality. In the Fourth and Fifth Meditations, Descartes provides further proofs for the existence of God and contends that the external world can be known with absolute certainly as long as we operate in the realm of clear and distinct ideas. The Sixth Meditation is considered by many critics Descartes' most original contribution to modern philosophy. Here he methodically analyzes the relation between the human soul and the body. Descartes defines the mind (or soul) as a purely volitional and indivisible thinking substance. However, he views the body as a passive object for sensations and says that it is no different than any other physical object, whose essence is extension. Although he later suggests that the mind and body are closely related, he maintains a clear distinction between the two, explaining that he can imagine the mind existing independently of the body. This distinction is seen by many commentators as the starting point of modern philosophy, and is the basis for Cartesian dualism.
The Meditations suggested new ways of conceiving of the rational universe, both physical and spiritual. Although some of his ideas were strongly opposed by contemporary religious thinkers, they were very influential in directing the course of the scientific revolution of the seventeenth century as well as the rationalism of the eighteenth-century French Enlightenment. Descartes' dualism was eventually eclipsed by the monistic systems of Benedictus de Spinoza, Gottfried Wilhelm von Leibniz, and Georg Wilhelm Friedrich Hegel. However, as late-nineteenth-century philosophy turned away from grand systems and focused its attention on the thinking subject, Descartes' ideas elicited renewed interest among philosophers and scientists. For example, the influence of Cartesian rationalism can be discerned in such important modern schools of thought as phenomenology and structuralism. Cartesian thinking has affected researchers in a variety of fields, including psychology and linguistics, as evidenced by Noam Chomsky's strong emphasis on innate, mental, non-empirical factors operant in the process of language acquisition. So, the Discourse on Method and the Meditations continue to be central to the Western intellectual tradition.