DESCARTES, RENÉ

René Descartes (1596–1650) was born in La Haye (now Descartes), France, on March 31, and he died in Stockholm, Sweden, on February 11. Although of Roman Catholic heritage, he lived in a region controlled by Protestant Huguenots at a time when Protestants and Catholics were frequently at war. His inherited wealth allowed him freedom to study and travel around Europe. He made important contributions to metaphysics, mathematics, and physiology. In mathematics, he invented coordinate geometry, which combines algebra and geometry into a powerful tool for the mathematical study of the physical world. Although he offered proofs for the existence of God and the immortality of the soul, he was suspected of being an atheistic materialist, and lived in fear of persecution. When Galileo Galilei (1564–1642) was condemned in 1633 as a heretic for teaching that the earth revolved around the sun, Descartes suppressed any publication of his agreement with Galileo. After Descartes's death, his books were put on the Catholic Church's Index of Prohibited Books.

Because he broke away from scholastic Aristotelianism and thought through the philosophic implications of a new science of nature, Descartes is often called the founder of modern philosophy. Using six ideas—doubt, method, morality, certainty, mechanism, and mastery—he set the stage for modern science in a way that has had lasting impact while being subject to continuous debate.

Doubt and Method

Descartes's most famous book is the Discourse on Method (1637), which is divided into six parts, each developing one of the key ideas that run throughout his writing. In Part One, he presents the idea of doubt. He rejects all traditional thinking because it does not produce proven conclusions that can guide life. The traditional liberal arts education promotes philosophical disputes that are never resolved. Similarly, the moral customs of people around the world are contradictory, and there is no reliable way to resolve this confusion. So Descartes decides to turn inward, to seek within himself some source of conclusive knowledge.

Although modern science often seems to require doubting all traditional beliefs and customs, historians of science have noticed that modern science depends on intellectual traditions. Scientists tend to work within what Thomas S. Kuhn (1922–1996) called "paradigms," broad intellectual frameworks that organize research. To doubt everything received from one's society would deprive one of any starting point for inquiry. And insofar as science is a collective enterprise, it requires that scientists share social norms of thought and conduct. When scientists challenge a traditional belief, it is because they have found resources within their inherited traditions for doing so. Even Galileo's challenge to the traditional idea that the earth was the center of the universe arose from his appeal to an alternative, heliocentric theory that was thousands of years old.

In Part Two, Descartes presents the idea of method. He summarizes his method for scientific inquiry in four rules:

1. accept only those ideas that are so clearly and distinctly present to the mind as to be self-evident,
2. divide difficult problems into simple parts that are manageable,
3. solve problems by moving in small steps from simple to complex,
4. survey every part of the reasoning so that nothing is overlooked.

Descartes has formulated these rules of scientific method by generalizing from the procedures in geometrical demonstrations, in which one moves from self-evident principles (definitions and axioms) to solve complex problems by moving step by step from simple ideas to more complex propositions.

Many philosophers of science question the adequacy of the Cartesian method for explaining modern science. Michael Polanyi (1891–1976), for example, argued that there is always a personal judgment in scientific discovery that cannot be reduced to the formalized procedures demanded by such a method. The insight for grasping fruitful ideas in scientific research does not arise from an impersonal method. Jacques Hadamard (1865–1963) surveyed the lives of some famous mathematicians to show that even mathematical reasoning depends on personal, intuitive judgments that go beyond formal logic.

Morality and Certainty

In Part Three, Descartes presents the idea of morality. He admits that his scientific method could not give him moral knowledge to guide his conduct. So he had to adopt a "provisional morality" by which he could live while working to complete his intellectual project. His provisional moral code consists of four rules:

1. accept whatever customs, laws, and religious beliefs prevail in one's country;
2. act decisively according to the most probable opinions as if they were absolutely certain;
3. change desires rather than the world;
4. realize that the pursuit of truth is the best life for an intellectual person such as himself.

If Cartesian scientists cannot derive morality from their science, then they have to accept whatever moral and religious customs happen to be traditional in their society. This suggests a fundamental problem with modern science—that progress in scientific knowledge does not bring progress in moral knowledge. Cartesian scientists cannot even provide a scientific argument for the moral worth of a life devoted to science. The life of Cartesian science is incoherent. On the one hand, Cartesian scientists doubt everything and refuse to accept anything that is not proven true. On the other, they must accept the moral and religious prejudices of their society because their science cannot produce moral and religious knowledge. Ultimately, this could lead to moral nihilism with the thought that moral value is beyond scientific knowledge and must be left to unexamined prejudice. One must wonder, therefore, whether a scientifically grounded morality is possible.

In Part Four, Descartes presents the idea of certainty. "I think, therefore I am." This most famous claim of Descartes captures his thought that while doubting everything, he cannot doubt his existence, because this is confirmed by his very act of doubting. To doubt is to think, and to think presupposes his existence as a thinker. Beyond this, another idea comes to him—the idea of a perfect being—and this leads him to infer that God's existence is a self-evident certainty. From having the idea of God as a perfect being, Descartes concludes that God must exist, because if he did not exist, he would not be perfect. Descartes derives this ontological argument for God's existence from Anselm of Canterbury (1033 or 1034–1109).

Few people have found the ontological argument a persuasive proof for God's existence, and Descartes's restatement of the argument is weak. This has led some readers to suspect that he is not serious about the argument, and that it is part of his provisional morality to profess belief in the religion of his country to protect himself from persecution. Some readers see this as an indication that modern science as Descartes conceives of it is inherently atheistic.

"I think, therefore I am." Is this an immediately self-certifying truth? Or does it rather, as Friedrich Nietzsche (1844–1900) argued in Beyond Good and Evil (1886), illustrate "the prejudices of philosophers"? How does Descartes know that if there is thinking, there must be an "I" to do the thinking? How does he even know what thinking is? Has he perhaps confused thinking with feeling or willing? One could easily continue asking such questions to point out the numerous assumptions buried in Descartes's seemingly simple intuition, assumptions that are not self-evident, assumptions in need of proof if the Cartesian method is to be upheld. One might conclude that even the most rigorous science cannot attain complete certainty, because every proof depends ultimately on some fundamental assumptions that cannot themselves be proven.

Mechanism and Mastery

In Part Five, Descartes presents the idea of mechanism. He expresses reluctance to fully state his mechanistic view of the world, because it would be unpopular. He sketches his physics, explaining how the universe could have emerged through purely mechanical laws. He explains how all life, including the human body, can be explained as governed by mechanical causes. He declares, however, that the "rational soul" of a human being cannot be derived from the mechanical laws of nature, and therefore it must have been specially created by God.

Historians of science have identified Cartesian mechanism as fundamental for modern science. Prior to the seventeenth century, people generally understood nature through the metaphor of the world as a living organism. The Earth was a nurturing Mother. But modern Cartesian science understood nature through the metaphor of the world as a dead machine. The earth was matter in motion.

This mechanical view of the world was criticized as atheistic materialism, because it seemed to deny the immaterial and immortal reality of God and the soul. Descartes defended himself against such criticisms by affirming his belief in God and the soul. He insisted that material body and immaterial soul were two utterly different substances. In his Treatise of Man (1664), Descartes explained the physiology of the human body and brain as matter in motion determined by mechanical forces. This was not published until after his death, because he feared it would be too unpopular. Later, Julien Offray de La Mettrie (1709–1751) argued in his book Man a Machine (1748) that Descartes had shown that all living beings—including human beings—were merely machines. La Mettrie suggested that Descartes's dualistic separation between body and soul was only a trick to protect himself against persecution from the theological authorities.

The view of the human mind as a computational mechanism has been a powerful influence in the modern science of the brain. This has led some computer scientists to the thought that sufficiently complex computers will eventually replicate or surpass human intelligence. In some stories by Isaac Asimov (1920–1992), robots become Cartesian thinkers, declaring "I think, therefore I am!" But some prominent scientists such as John C. Eccles (1903–1997) argue that human self-conscious thought manifests the uniquely human power of an immaterial soul. So the debate continues over whether science can fully explain the human soul as a material mechanism.

In Part Six, Descartes presents the idea of mastery. The general aim of scientific research should be conquering nature for human benefit. The specific aim should be making such advances in medical science that human health would be improved dramatically, perhaps even to the point of prolonging life and thus conquering death. In this way, human beings would become "the masters and possessors of nature."

Descartes thus joins the project of Francis Bacon (1561–1626) for directing modern science and technology to the mastery of nature for relieving human suffering and enhancing human life. In support of this project, Descartes offers a distinctly modern vision of human beings scientifically constructing and technologically manipulating nature so that they can become like God.

LARRY ARNHART

SEE ALSO Nature;Newton, Isaac;Scientific Revolution.

BIBLIOGRAPHY

Asimov, Isaac. (1950). I, Robot. New York: Doubleday.

Descartes, René. (1988). Descartes: Selected Philosophical Writings, trans. John Cottingham, Robert Stoothoff, and Dugald Murdoch. Cambridge, UK: Cambridge University Press.

Descartes, René. (2003). Treatise of Man, trans. Thomas Steele Hall. Amherst, NY: Prometheus Books. Originally published, 1664.

Hadamard, Jacques. (1954). An Essay on the Psychology of Invention in the Mathematical Field. New York: Dover.

Kuhn, Thomas S. (1996). The Structure of Scientific Revolutions, 3rd edition. Chicago: University of Chicago Press.

Lachterman, David Rapport. (1989). The Ethics of Geometry. New York: Routledge. Study of Descartes' modern idea that mathematics is a god-like activity of construction.

La Mettrie, Julien Offray de. (1994). Man a Machine, trans. Richard A. Watson and Maya Rybalka. Indianapolis, IN: Hackett. Originally published, 1748.

Lampert, Laurence. (1993). Nietzsche and Modern Times: A Study of Bacon, Descartes, and Nietzsche. New Haven, CT: Yale University Press. Shows how Descartes contributed to modern break from Socratic philosophy and biblical religion.

Lange, Frederick Albert. (1925). The History of Materialism, 3rd edition, trans. Ernest Chester Thomas. London: Routledge and Kegan Paul. Demonstrates the importance of Cartesian mechanism in the history of materialism.

Merchant, Carolyn. (1980). The Death of Nature: Women, Ecology, and the Scientific Revolution. San Francisco: Harper and Row.

Nietzsche, Friedrich. (1968). Basic Writings of Nietzsche, trans. and ed. Walter Kaufmann. New York: Random House.

Polanyi, Michael. (1958). Personal Knowledge. Chicago: University of Chicago Press.

Popper, Karl R., and John C. Eccles. (1977). The Self and Its Brain: An Argument for Interactionism. New York: Springer International. Scientific and philosophical arguments for immaterial soul interacting with material brain.

Watson, Richard A. (2002). Cogito, Ergo Sum: The Life of René Descartes. Boston: David R. Godine.