Descartes, Ren (1596–1650)

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DESCARTES, REN (1596–1650)

DESCARTES, RENÉ (1596–1650), French philosopher, mathematician, and scientist. Descartes was one of the most important intellectual figures of seventeenth-century Europe. His thought, often regarded as ushering in the "modern" period of philosophy, represented a revolutionary attempt to break from the restrictive and tradition-bound medieval Scholastic model that governed the universities and that was dominated by the method and categories of Aristotelian philosophy. By the time of his death, Descartes's influence extended across Europe and into various intellectual domains, including theology, medicine, and even rhetoric.

In 1633 Descartes, who had already written a treatise on method, Regulae ad Directionem Ingenii (Rules for the direction of the mind), was ready to publish a book on cosmology and physics, Le Monde (The world). But Galileo's condemnation that year by the church for propounding scientific ideas very much like what Descartes was about to present, including a heliocentric picture of the universe and a purely mechanistic account of nature's operations, caused him to withhold the work. He first came to public attention with the publication of his Discours de la méthode pour bien conduire sa raison et chercher la verité dans les sciences (1637; Discourse on the method of rightly conducting one's reason and reaching the truth in the sciences) and the ground-breaking essays in geometry, optics, and meteorology that it accompanied. The Meditationes de Prima Philosophiae (1641; Meditations on first philosophy), often regarded as Descartes's philosophical masterpiece, is a short work in epistemology and metaphysics. It was not until his magisterial Principia Philosophiae (1644; Principles of philosophy) that Descartes offered a complete and systematic presentation of his metaphysical and scientific views; he hoped that the work would become a standard textbook in university curricula and supplant the Aristotelian Scholastic works then in use.

Descartes lived most of his adult life in the Netherlands, having left France in search of peace and solitude to pursue his inquiries. His fame led to an invitation to Sweden by Queen Christina in 1649; with misgivings about giving up his quiet, familiar life in the Dutch countryside, he reluctantly joined her court. It was not long, however, before he fell ill from the rigors of the routine imposed upon him in the harsh Swedish winter and died of pneumonia.

Philosophy, for Descartes, encompasses the whole of human knowledge, systematically ordered, and can be compared to a tree. Its roots are metaphysics, or "first philosophy" (including the theory of knowledge); its trunk is physics; and its branches are all of the particular sciences (medicine, ethics, mechanics) that depend on the most general physical principles. Certainty in philosophy or science can be achieved only if one proceeds methodically from well-established first principles to explanations in the particular disciplines by means of a proven method.

In the Meditations, Descartes begins by taking the reader on a journey of intellectual self-discovery. His goal is to determine what exactly can be known for certain, not just about the world around us but especially about ourselves. Even under the most adverse skeptical assumptions about the reliability of our senses and our rational faculties, we can always be absolutely certain of our own existence. As he so famously expresses it in the Discourse on Method, the reasoning represented by the proposition "I think, therefore I am" (Cogito ergo sum) can never be doubted. This single epistemological nugget can serve as the foundation for a host of other certainties. For once I know my own existence and my nature as a thinking being—endowed with certain thoughts or clear and distinct ideas—I can establish not only that God, an absolutely perfect being, exists and cannot be a deceiver, but also that this benevolent God created me with my rational faculties. Thus, to the extent that I use those faculties properly and give my assent only to what I clearly and distinctly perceive, I cannot go wrong and will obtain true beliefs about myself and about the external world.

Among the truths I will thereby discover is the real distinction between mind and matter. One of Descartes's most important and lasting legacies to philosophy is the doctrine that has come to be known as "dualism." Mind and matter (or body), according to Descartes, are two essentially and radically different kinds of substance. Mind is unextended, indivisible, simple thinking; its modes or properties are ideas or thoughts. Matter, on the other hand, is nothing but extension or dimensional space, and is therefore divisible; its modes are shape, size, and mobility. There is nothing materialistic about the mind, and nothing mental or spiritual about the body.

This doctrine is of great importance not only for understanding the nature of the human being, who is a composite—or, to use Descartes's phrase, a "substantial union"—of these two substances, but also for science. According to Descartes, the physical world is nothing but passive matter or extension, divisible ad infinitum into material parts. The active, spiritlike "forms" of the Aristotelian world picture have been banished from nature. All natural phenomena, no matter how complex, and regardless of whether they are terrestrial or celestial, are henceforth to be explained solely in terms of matter and the motion, rest and impact of its parts. Descartes's separation of mind and matter was a crucial step in the scientific revolution of the seventeenth century and laid the metaphysical foundations for the mechanical philosophy that dominated the period until Isaac Newton (1642–1727).

See also Aristotelianism ; Cartesianism ; Galileo Galilei ; Philosophy ; Scholasticism ; Scientific Revolution .

BIBLIOGRAPHY

Primary Sources

Descartes, René. Oeuvres de Descartes. Edited by Charles Adam and Paul Tannery. 12 vols. Paris, 1964–1976.

——. The Philosophical Writings of Descartes. Translated by John Cottingham, Robert Stoothoff, and Dugald Murdoch. 2 vols. Cambridge, U.K., 1984–1985.

——. The Philosophical Writings of Descartes. Vol. 3, The Letters. Translated by John Cottingham, Robert Stoothoff, Dugald Murdoch, and Anthony Kenny. Cambridge, U.K., 1991.