The Founder of the Modern Mind

By Gabriel Blanchard

If all philosophy can be called a footnote to Plato, all modern philosophy can be called a footnote to Descartes.

From a time traveler’s perspective, the seventeenth century might seem like a good time to go somewhere other than Europe. Besides multiple decades-long religious wars, fresh eruptions of the Black Death—which had not disappeared, but merely became dormant after the infamous plague of 1347-1351—took place across the continent, claiming the lives of tens of millions. On the other hand, a number of exciting developments took place in European culture, including major advances in technology (such as the telescope and microscope), the sciences (led by figures like Boyle and Galileo), and mathematics (including two independent discoveries of calculus); nor, even apart from the upheavals of the Reformation, was philosophy any exception. Just a few years before the turn of the century, a man was born to a Catholic family living in a Protestant-dominated province of France; he would go on to initiate a change in western philosophy more overwhelming than any since the Christianization of European civilization. That man was René Descartes.

Descartes did not at first take much interest in philosophy. After obtaining a degree in law, he became a mercenary in the service of the Dutch Republic (where he would later settle for about twenty years and achieve much of his most important work), then at war with the Holy Roman Empire. While thus employed, he also did extensive work on physics and mathematics. Many modern conventions in the latter subject are of Descartes’ coinage, like the Cartesian coordinate system or “x-y graph.”

But in the November of 1619, his life was radically altered. He had a series of three dreams in which he believed a spirit unveiled to him a new philosophy, or philosophic method. This included convictions of the unity of all truth and the universal applicability of mathematical reasoning, such that by taking any one truth and analyzing it logically and scientifically enough, one could thereby arrive at all truth. This should not be taken too literally—Descartes did not mean that all truth can literally be measured in numbers! Rather, he established a four-step process that he considered a universal guide to all topics of thought:

  1. Begin with what is self-evident and clear.
  2. Divide each problem into its simplest parts.
  3. Solve each problem by going from simpler parts to the more complex.
  4. Go back and check the reasoning.

This was the beginning of modern rationalism—a school of thought (or more properly, a group of such schools) that treats reasoning, in contrast to sense experience or authority, as the principal or best or most important source of human knowledge.

No more useful inquiry can be proposed than that which seeks to determine the nature and scope of human knowledge.

This leads us to his most celebrated work, the Discourse on the Method. Though not his only book on philosophy, or even his first, the Discourse lays out the general basis and character of Cartesian philosophy from the ground up. Perhaps inspired by the contentious world in which he lived, Descartes begins with a stance of radical doubt, in the hope of eliminating all errors caused by flawed assumptions. Our senses can be fooled or faulty, authorities can lie, our preconceptions are often wrong or incomplete. Is there anything that simply cannot be doubted? Descartes answered that there was, namely one’s own existence; the famous remark Cogito ergo sum or “I think, therefore I exist,” comes from this book. From here, he proceeded step by step to reconstruct all of reality—up to and including his Catholic faith—on the basis of unaided reason.

That is, Descartes succeeded in this project to his own satisfaction. Others were less convinced: his contemporary Blaise Pascal accused him of deism, and the Catholic Church placed Descartes’ writings on the Index of Forbidden Books. (However, this only took place thirteen years after his death, and he was not called upon to retract any of his ideas while alive.) Cartesian philosophy also made little headway in England, where both its Catholicism and its rationalism were met with distaste by the prevailingly Anglican, pragmatic culture.

But what was truly dramatic in Cartesianism was a shift in focus. Philosophy has always been about truth—its name literally means “the love of wisdom”—and this did not change with or after Descartes. The characteristic question posed by philosophers, however, did; where a North African librarian or a Byzantine monk would probably ask “What is true?”, René Descartes asked instead “What can I be certain of?” This changes the locus of the question, so to speak, from reality to human knowledge. Where the first way of asking about truth prevails, it leads naturally to treating metaphysics* as the chief or controlling branch of philosophy, while where the second is dominant, epistemology** tends to become the controlling branch. Many thinkers, both religious and otherwise, interpret this as a transition from an essentially religious framework rooted in divine authority to an anthropocentric one, rooted in the individual. Be that as it may, it certainly accompanied and perhaps caused such a shift in the general culture of Europe; this shift has been credited with, or blamed for, a multitude of upheavals in western history, from the scientific revolution to the rise of secular democracy.

*Metaphysics is the kind of philosophy that deals with what is real (this sub-branch is called ontology) and how reality works (which used to be what the word physics meant, though now of course it strictly refers to how the material world works).
**Epistemology is the kind of philosophy that deals with knowledge, especially with how we know things, what kinds of knowledge there are, and what confidence we can have in our knowledge.


Gabriel Blanchard is (for all he knows to the contrary) CLT’s editor at large and a freelance author. He lives in Baltimore, MD.

If you enjoyed this piece, you might like some of our other media on “Great Books” education, like our podcast, Anchored. Here at the Journal, we have an ongoing series on the history of ideas and periodic posts from our highest-scoring students; this post is one among many profiles of the men and women of our Author Bank.

Published on 28th November, 2022. Page image of a sixteenth-century line drawing of an ore-crushing machine, powered by a water wheel.

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