BIOGRAPHY

René Descartes was born into the family of a minor noble in the town of La Haye in Touraine, France. At ten, René began a nine-year course of studies at the Royal Jesuit College of La Flèche. There he studied the humanities, theology, and philosophy (which included morals, logic, mathematics, metaphysics, and science). Though he did well in school, he was disillusioned by the uncertainty of his studies and their contradictory conclusions. Like modern students, he felt overwhelmed by the many opinions he encountered. He later wrote in his Discourse on Method that upon completion of his course of study, "I found myself embarrassed with so many doubts and errors that it seemed to me that the effort to instruct myself had no effect other than the increasing discovery of my own ignorance."

However, there was one discipline in which he found the certainty he was seeking: mathematics. The truths of mathematics were assured regardless of one's metaphysical or epistemological assumptions: 2 + 2 = 4 whether one is a Platonist or an Aristotelian; 3 x 3 = 9 whether one is a Roman Catholic or a Protestant. Given mathematical certainty, Descartes found it odd that on such a firm basis "no loftier edifice had been reared."

Left a modest inheritance by his father, Descartes spent the rest of his life seeking the certainty not found in college. After receiving a law degree at Poitiers in 1616, he served as a gentleman volunteer in the army of Maurice of Nassau. While soldiering, he began to develop the idea of connecting mathematical certainty with philosophy. In 1619, he had a series of dreams convincing him that the "spirit of truth" was leading him and that he had divine approval for his studies. For the next ten years, while traveling and serving in the army, he developed his ideas. In 1628, he had a debate with Chandoux, a scientist who claimed that science could only be founded on probability. Descartes argued eloquently that knowledge must be based on certainty and that he had a system that provided that basis. Encouraged by others to develop his system, he retired to Holland, where he found a greater degree of intellectual freedom and spent the next twenty years writing and publishing his ideas. His major philosophical works include Rules for the Direction of the Mind (written 1628, but not published until 1701), Discourse on Method (published in 1637 as a preface to the essays Geometry, Dioptric, and Meteors), and Meditations on First Philosophy (1641). Descartes also published seven sets of Objections to the Meditations of such thinkers as Hobbes, Arnauld, and Gassendi, accompanied by his Reply to Objections. In addition to his work in philosophy, Descartes made major contributions to the fields of optics, anatomy, physiology, and mathematics (especially analytic geometry in which "Cartesian coordinates" are still used).

Descartes chose to write his works in French as well as Latin in order to reach beyond the academics to a wider audience. His writings did, indeed, reach learned people throughout Europe and that fact, unfortunately, led indirectly to his death. In 1649 Queen Christina of Sweden invited Descartes to join a circle of leading thinkers to instruct her in philosophy. Although he initially resisted the invitation, he finally felt compelled to accept. Upon arriving in Sweden, Descartes discovered that Queen Christina had time to see him only at five each morning. Descartes had been used to lying in bed until late in the morning, reflecting and philosophizing. Within a year the rigorous new schedule, together with Sweden's harsh weather, led to his death.

BASIC THOUGHT

Like Bacon before him, Descartes began his philosophy by sweeping away all the "errors of the past." Whereas Bacon turned to empirical observation to escape the "tyranny" of the past, Descartes turned to mathematics, specifically geometry. He began by establishing twenty-one Rules for the Direction of the Mind. He would begin by finding knowledge that he could "clearly and evidently intuit, or deduce with certainty." Then he would build from this knowledge deductively, one step at a time. This procedure would parallel the geometrical method of moving with deductive certainty from postulates to axioms. His Meditations on First Philosophy, reprinted here (complete) in the latest John Cottingham translation, chronicles this process.

The key was to find the knowledge that he could "clearly and evidently intuit" that could serve as his starting point. Although uncertainty and doubt were the enemies, Descartes hit upon the idea of using doubt as a tool or a weapon. Instead of fighting doubt, he would use it to find certainty. He would use doubt as an acid to pour over every "truth" to see if there was anything that would not be dissolved, any "truth" that could not be doubted. Some of his doubts may seem extreme (such as that the earth may not exist or that I may be dreaming all this), but in order to find one-hundred percent certainty he had to find a starting point with zero percent doubt.

After subjecting all his knowledge to the acid of doubt, he concluded that there was one thing he could not doubt: that he was doubting. The one fact the acid of doubt could not dissolve was doubt itself. This meant there had to be an "I" who was doing the doubting. Even if he were deceived about everything else, he had to exist in order to be deceived. This led Descartes to his famous statement, Cogito ergo sum, meaning "I think, therefore I am" (although these exact words do not appear in the Meditations). Here was the "clearly and evidently intuited" knowledge, the starting point, that Descartes had been seeking.

Like Bacon before him, Descartes began his philosophy by sweeping away all the "errors of the past." Whereas Bacon turned to empirical observation to escape the "tyranny" of the past, Descartes turned to mathematics, specifically geometry. He began by establishing twenty-one Rules for the Direction of the Mind. He would begin by finding knowledge that he could "clearly and evidently intuit, or deduce with certainty." Then he would build from this knowledge deductively, one step at a time. This procedure would parallel the geometrical method of moving with deductive certainty from postulates to axioms. His Meditations on First Philosophy chronicles this process.

The key was to find the knowledge that he could "clearly and evidently intuit" that could serve as his starting point. Although uncertainty and doubt were the enemies, Descartes hit upon the idea of using doubt as a tool or a weapon. Instead of fighting doubt, he would use it to find certainty. He would use doubt as an acid to pour over every "truth" to see if there was anything that would not be dissolved, any "truth" that could not be doubted. Some of his doubts may seem extreme (such as that the earth may not exist or that I may be dreaming all this), but in order to find one-hundred percent certainty he had to find a starting point with zero percent doubt.

After subjecting all his knowledge to the acid of doubt, he concluded that there was one thing he could not doubt: that he was doubting. The one fact the acid of doubt could not dissolve was doubt itself. This meant there had to be an "I" who was doing the doubting. Even if he were deceived about everything else, he had to exist in order to be deceived. This led Descartes to his famous statement, Cogito ergo sum, meaning "I think, therefore I am" (although these exact words do not appear in the Meditations). Here was the "clearly and evidently intuited" knowledge, the starting point, that Descartes had been seeking.

Having established that there is an "I," a self, a starting point, Descartes began to explore the nature of this "I":

But what then am I? A thing that thinks. What is that? A thing that doubts, understands, affirms, denies, is willing, is unwilling, and also imagines and has sensory perceptions.

Among the ideas of this "thinking thing" called the "I" is the idea of a perfect God. Descartes went on to argue that nothing less than God could have caused the idea of God. He therefore concluded with a second certainty: that God exists.

From here Descartes moved to his third certainty: We have a strong tendency to believe in the existence of a reality beyond our consciousness. If there is no such external world, then we are terribly deceived. But a perfect God would not allow us to be unavoidably deceived, since deceit implies imperfection. Accordingly, we can conclude that we are not misled about those natural beliefs, such as the existence of an external world, so long as they can withstand the scrutiny of reason and are not willfully disregarded.

Descartes had now established a basis for accepting the "obvious" truths he had thrown out earlier by his method of doubt. He had at the same time identified the criterion needed to distinguish the foundational truths upon which his knowledge rested, namely, the criterion that a truth must be "clearly and distinctly perceived." An example of his rationalistic dependence upon such intuitions is his claim that the essential nature of a material object can only be known intuitively, not through sense perceptions.

This drawing from Descartes' Optics illustrates the problem of mind body interaction. The woman points at the arrow she sees because her muscles contract. But where exactly is the mind in all of this?

One final point needs to be noted. The "I" that Descartes found at the end of his methodological doubting was "entirely distinct from the body." This "I" was an immaterial mind, a "spiritual" thing. The body is an "extended, non-thinking thing." As such, it is part of the material world, subject to the same laws of motion as a billiard ball. The "I," or the mind, on the other hand, is not bound by physical laws. This Cartesian distinction leads to a problem about the relationship between body and mind-- a problem with which we still struggle today. (For a reading on this issue, click here.)