René Descartes was born in La Haye, known today as La Haye-Descartes in 1596. After studying classical literature, history, rhetoric, and philosophy at the collège des Jésuites de la Flèche, he obtained his law degree from the University of Poitiers. In 1618, he enrolled in the Dutch army commanded by the prince Maurice of Nassau. Upon invitation by Queen Christina of Sweden, Descartes moved to Sweden in 1649 in order to tutor her in philosophy. Shortly thereafter he became ill with pneumonia and died in early 1650.
René Descartes was born in La Haye, known today as La Haye-Descartes in 1596. After studying the humanities (classical literature, history, rhetoric) and philosophy at the collège des Jésuites de la Flèche, he obtained his law degree from the University of Poitiers. In 1618, he enrolled in the Dutch army commanded by the prince Maurice of Nassau. He met the Dutchman Isaac Beeckman, who encouraged his interest in mathematics and physics. Shortly after, in 1619, Descartes joined the Bavarian army, where he used his downtime to return to his interest in geometry.
Descartes soon began focusing on finding a general method, which would resolve all geometrical problems. In concentrating on this rather vast project, he soon conceived the possibility of discovering a methodthat could solve all the problems that the human spirit might present as he began to think of the sciences as all branches of one tree that together form one entity. After a series of dreams, he became convinced that God had personally chosen him to accomplish this task. He withdrew to Holland once more, where after nine months he had found the essential base to his theories, which would become the basis for his later Meditations. His work leading to le Monde (the World) was put aside, when he learned that the Inquisition had condemned Galileo for his teachings on the movement of the Earth (1633). Since Galileo's theories and in particular the heliocentric model first proposed by Copernicus were essential to his own physics, it seemed prudent to focus on another way to publish his own theories.
Meanwhile, Descartes was also the founder of analytical geometry and is greatly appreciated for his mathematical and other scientific contributions. He wrote a treatise on dioptrics (thus contributing to the science of optics) and another scientific treatise on meteorology. He later combined these two treatises with one on geometry, which he then prefaced with a short introduction, the Discourse on Method. While his writings were critiqued widely by the theologians of his time, the three studies had a major influence on science. It is, however, the preface which has received the most general notice. It has been translated into many, many languages, reprinted innumerable times, and is oft the subject of university courses worldwide.
Descartes's Discourse on Method summarizes his experience and studies that lead to his discovery of his method as well as the precepts which constitute it. By tracing his own experiences and development, he can show how the individual consciousness comes to know itself, its God, and its world. The first part of the Discourse on Method thus focuses on his academic training and his attraction to mathematics because of its use of reason and because of the clarity and certainty of its knowledge. He much appreciated how the mathematical model advances step by step from one indisputable conclusion to the next. He thus proposes to introduce into the fields of philosophy and physical science the clear and consistent deductive methods he had experienced in the field of mathematics. Only through such a systematic approach can knowledge be established. In addition, one should start with the most simple notions, building step by step toward the more complex. In so doing, it remains important to reject any statement that can be doubted, retaining only those that are self-evident and cannot be doubted. Only thus, proposes Descartes, can one build a solid base for knowledge. Descartes chooses, furthermore, to illustrate his method in action in the Discourse. The deductive or Cartesian method as it was often called becomes all the more compelling and convincing.
The second part of the Discourse reveals the four principal rules at the base of his method. First, he only accepts something as true when he has known it to be both evident and without doubt true. Second, he divides each difficulty he encounters into as many parts as necessary, which he then analyzes in order to better resolve any problems. Third, he orders his thoughts by progressing, step by step, from the most simple to the most complex. Fourth, he enumerates everything, making sure to omit nothing. Descartes's method rejects the overarching principle of authority, preferring the principle of rational evidence. For this reason, he defines the role of analysis, of synthesis, and of the experimental method, believing that his method teaches the "true order" and the importance of enumerating all the possible circumstances of what one seeks.
The third section of the Discourse presents the three rules governing his morality ("une morale par provision"). First, Descartes chooses to obey the laws and customs of his country, to respect his religion and to govern himself always in moderation. Second, he opts to remain as firm as possible in his actions. Third, he attempts to attain detachment for all that is outside of himself (e.g., worldly goods) in order to focus on "cultivating" his reason, and thus, by extension, using his method to further his knowledge of what is true. In following these precepts, Descartes aims to be the happiest he can be. His morality governs his behavior towards others, towards himself, and towards his world.
In the fourth section, Descartes uses his method of systematic doubt in order to arrive at the very core of his system. He thus confirms his own existence. This demonstration of his own existence as indisputable is elegantly simple. In short, he argues, man is often deceived by his senses and thus supposes something to be true which is not. Man, however, does not know that he is being deceived in supposing this non-true thing to be true. It is thus possible at any moment to be deceived. Yet, man cannot doubt that he is doubts - for if he were to doubt that, he would be doubting. From this doubt, which as Descartes notes is only one sort of thinking, he recognizes the potential to think the self. Once he recognizes this, he confirms his existence. After claiming himself to exist, he recognizes his own less than perfect state and thus the potential existence of a Perfect Being, and by extension, the indisputable existence of God.
Once he has used his method to prove the existence of God and by extension, the notion of infinity, he addresses questions of the physical in his fifth section, which offers conclusions related to the notion of the heart and other anatomical problems. His philosophy separates mind from body, although he aims to explain how they work together. In addition, he uses his detailed explanations of the heart to show that man and beast are different due to the ability of man to use his reason to formulate words which communicate his thoughts. The ability to reason confirms the existence of the soul.
The sixth and final section distinguishes between the philosopher's desire to seek clarity in his thoughts and actions and his need to publish them, which arises from the desire to improve humankind's material existence. Descartes outlines a program for a further investigation of nature and urges his fellow and future colleagues to continue in his path. His "new," more "practical" philosophy greatly influenced the many philosophers that followed him, whether they resisted or continued to apply his philosophical considerations.
Descartes's Méditations métaphysiques (Metaphysical Meditations), which further develops his system, appeared in 1641. In 1644, Descartes published, in Latin, the Principles of Philosophy in which he discussed Aristotle's works. In his last work, the Traité des passions de l'âme (The Passions of the Soul), published in 1649, Descartes argued that the mind is not directly affected by any part of the body but by the pineal gland in the brain. All sensations travel through the body, arriving to this gland, which then communicates to the mind. Thus mind and body are separate. One's reason and will can and should thus dominate over the passions for the betterment of one's soul. In short, according to Descartes, passions (admiration, love, hate, desire, joy, sadness) can be judged good or bad in relation to their link to reason. In 1649, upon invitation by Queen Christina of Sweden, Descartes moved to Sweden in order to tutor her in philosophy. Shortly thereafter he became ill with pneumonia and died in early 1650.
E. Nicole Meyer is Associate Professor of Humanities at the University of Wisconsin -- Green Bay.\