In this blog post, I will summarize the structure and main content of Descartes’ “Discourse on the Method,” as well as the author’s life and intellectual context.

Publication and Basic Information

“Discourse on the Method” was first published anonymously in 1637 by the Dutch publisher Jan Maire when Descartes was 41 years old.
This was Descartes’ first published work; its original full title is ‘Discourse on the Method for Leading the Mind Correctly and for Seeking Truth in the Sciences, and an Attempt at Applying This Method to Refractive Optics, Meteorology, and Geometry’.
Of the book’s more than 500 pages, the first 78 pages constitute the “Discourse on the Method” itself, followed by brief prefaces to the three scientific treatises that follow.

The Six Parts and Key Content of the “Discourse on the Method”

As Descartes briefly outlines in the preface, the book is divided into six parts. Part I examines various disciplines, including traditional school education and Scholastic philosophy, and concludes that they lack certainty and are of little practical use in real life.
As a result, Descartes presents the background of how, after completing his studies, he set out on a journey, leaving behind books and lectures, to begin a new course of reflection.
In Part II, through his reflections in a German parlour, he presents a “method” for academic reform. This method is organized into four rules—evidence, analysis, synthesis, and enumeration—and is expected to serve as a universal procedure useful not only for solving mathematical problems but also for studying natural phenomena.
Part III deals with practical guidelines regarding morality (morals) and proposes three rules that can be applied to everyday life. This moral code is presented as a provisional and tentative ethics with Stoic overtones, and Descartes himself was unable to devise a new moral system that transcended it in the future.
Part IV deals with the foundations of metaphysics. Through methodological doubt, the “thinking self (mind),” “God,” and “the existence of the external world” are presented in succession. Here, the famous proposition “I think, therefore I am’ is adopted as the first principle and serves as the starting point for certain knowledge.
In this process, Descartes advocates mind-body dualism and develops an argument to prove the existence of God using Scholastic terminology and concepts. The key insight is that while the content of consciousness may be doubted, the very existence of the “I” that is conscious cannot be doubted.
Part 5 briefly outlines the core ideas of his “Treatise on the World,” which he ultimately never published. It describes his attempts to explain the universe and natural phenomena mechanically, his discussion of the differences between humans and animals, and his perspective on understanding the human body as a machine.
Part 6 depicts Descartes’ reaction upon hearing the shocking news of Galileo’s condemnation. It discusses the meaning of the study of nature, the philosophical attitude of humans seeking to dominate nature, the reasons for halting the publication of ‘The World’, and his motivation for preserving this text for posterity.
What emerges through these six parts is that Descartes’ method is both cautious and resolute. While he studied existing scholarship extensively and acknowledged its merits, he fundamentally subjected it to radical criticism and, as an alternative, proposed a new method composed of concise rules.
The “thinking self” as the starting point of his method, the dualism that forms the foundation of his system, and the metaphysical discussions on the mind and God together constitute the pillars of Descartes’ thought.
Each section of this book possesses genre-specific characteristics that differ from today’s academic classifications. It encompasses diverse fields—including the theory of knowledge, mathematics and methodology, ethics, metaphysics, astronomy, anatomy, and medicine—all of which demonstrate the prototype and orientation of modern scholarship, distinctly different from the traditions of the time.
Furthermore, the work reveals a highly polished autobiographical quality, as Descartes directly weaves his life story and thought process into the narrative through first-person narration; its status as an exceptional work written in French also establishes it as a model of the modern French spirit.

The Context of Descartes’ Life and the Formation of His Method

René Descartes was born in 1596 in La Haye, in the Touraine region of central-western France. This region was famous for its fertile farmland, and La Haye (now known as Descartes) was a sunny rural town.
His father served as a magistrate in the local court, and Descartes grew up as the son of a member of the legal nobility. Descartes enrolled at the Collège de La Flèche, a prestigious Jesuit school, where he spent eight years studying the humanities and Scholastic philosophy.
He then studied medicine and law for one year at the University of Poitiers, where he earned a bachelor’s degree in law. In 1618, he traveled to the Netherlands and enlisted as a cadet officer in the army of Maurice of Nassau.
During his stay in the Netherlands, he met the scientist Becke, from whom he gained the idea of applying mathematics to natural philosophy; they also conducted joint research on topics such as fluid pressure and the laws of falling bodies.
In 1619, amid news of the outbreak of the Thirty Years’ War, he joined the Catholic army under the Bavarian government in Germany. That winter, while sitting in a heated room in Neuburg and engaging in continuous reflection, he became convinced that he would be able to discover a universal method of inquiry. These reflections are later reflected verbatim in Parts II and III of his work.
After completing his military service, he traveled through Northern and Eastern Europe; following a brief return to France in 1622, he spent two years in Italy beginning in 1623. Upon his return to Paris, he interacted with scientists such as Mersenne and focused his attention on research in optics, geometric optics, the refraction of light, and explanations of rainbows.
In 1628, seeking an environment where he could devote himself to research and contemplation, he moved to the Netherlands. At first, he immersed himself in metaphysics; subsequently, prompted by reports of a solar halo observed in Rome, he began writing ‘The World’ in an effort to systematically organize the natural sciences as a whole.
However, upon hearing of Galileo’s condemnation, he abandoned plans to publish ‘The World’ and instead published three scientific treatises in 1637, prefaced by the ‘Discourse on the Method’.
He subsequently published his major work on metaphysics, ‘Meditations’ (1641); ‘Principles of Philosophy’ (1644), which presented his complete system, including natural philosophy; and ‘Treatise on the Passions’ (1649), which dealt with the union of mind and body and ethics.
In early 1649, he received an invitation from Queen Christina of Sweden; after some hesitation, he eventually traveled to Stockholm that fall. There, he worked on plans to establish an academic institution and wrote plays, but his health deteriorated due to early-morning lectures during the cold winter, and he died of pneumonia in February 1650.
Descartes’ method is of great significance in that it recognized the merits of existing scholarship while fundamentally reexamining its core and proposing simple yet rigorous rules, thereby charting the course for modern scholarship.