17 Things to Know About René Descartes

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The French polymath René Descartes (1596-1650) lived after the Renaissance, but he personified that age's interest in mathematics, philosophy, art, and the nature of humanity. He made numerous discoveries and argued for ideas that people continue to grapple with. (His dualist distinction between mind and the brain, for example, continues to be debated by psychologists.) Get to know him better!

1. NOBODY CALLED HIM RENÉ.

Descartes went by a nickname and often introduced himself as “Poitevin” and signed letters as “du Perron.” Sometimes, he went so far to call himself the “Lord of Perron.” That’s because he had inherited a farm from his mother’s family in Poitou, in western France.

2. SCHOOL MADE HIM FEEL DUMBER.

From the age of 11 to 18, Descartes attended one of the best schools in Europe, the Jesuit College of Henry IV in La Flèche, France. In his later work Discourse on the Method, Descartes wrote that, upon leaving school, “I found myself involved in so many doubts and errors, that I was convinced I had advanced no farther in all my attempts at learning, than the discovery at every turn of my own ignorance."

3. HIS DAD WANTED HIM TO BE A LAWYER.

Descartes’s family was chock-full of lawyers, and the budding intellectual was expected to join them. He studied law at the University of Poitiers and even came home with a law degree in 1616. But he never entered the practice. In 1618, a 22-year-old Descartes enlisted as a mercenary in the Dutch States Army instead. There, he would study military engineering and become fascinated with math and physics.

4. HE CHANGED CAREER PATHS THANKS TO A SERIES OF DREAMS.

In 1618, the Emperor of the Holy Roman Empire, Ferdinand II, attempted to impose Catholicism on anybody living within his domain. The result of this policy would be the Thirty Years' War. It would also prompt Descartes, a Catholic, to switch allegiances to a Bavarian army fighting for the Catholic side. But on his travels, he stopped in the town of Ulm. There, on the night of November 10, he had three dreams that convinced him to change his life’s path. “Descartes took from them the message that he should set out to reform all knowledge,” philosopher Gary Hatfield writes in the Stanford Encyclopedia of Philosophy.

5. HE COULD BE EASILY DISTRACTED BY BRIGHT AND SHINY OBJECTS.

In 1628, Descartes moved to the Netherlands and spent nine months doggedly working on a theory of metaphysics. Then he got distracted. In 1629, a number of false suns—called parhelia, or “sun dogs”—were seen near Rome. Descartes put his beloved metaphysics treatise on the back burner and devoted his time to explaining the phenomenon. It was a lucky distraction: It led to his work The World, or Treatise on Light.

6. HE LAID THE GROUNDWORK FOR ANALYTIC GEOMETRY ...

In 1637, Descartes published his groundbreaking Discourse on the Method, where he took the revolutionary step of describing lines through mathematical equations. According to Hatfield, “[Descartes] considered his algebraic techniques to provide a powerful alternative to actual compass-and-ruler constructions when the latter became too intricate.” You might have encountered his system in high school algebra: They’re called Cartesian coordinates.

7. ... AND THE REST OF WESTERN PHILOSOPHY.

Everybody knows Descartes for his phrase Cogito, ergo sum (which originally appeared in French as "Je pense, donc je suis"), or "I think, therefore I am." The concept appeared in many of his texts. To understand what it means, some context is helpful: At the time, many philosophers claimed that truth was acquired through sense impressions. Descartes disagreed. He argued that our senses are unreliable. An ill person can hallucinate. An amputee can feel phantom limb pain. People are regularly deceived by their own eyes, dreams, and imaginations. Descartes, however, realized that his argument opened a door for "radical doubt": That is, what was stopping people from doubting the existence of, well, everything? The cogito argument is his remedy: Even if you doubt the existence of everything, you cannot doubt the existence of your own mind—because doubting indicates thinking, and thinking indicates existing. Descartes argued that self-evident truths like this—and not the senses—must be the foundation of philosophical investigations.

8. HE'S THE REASON YOUR MATH TEACHER MAKES YOU CHECK YOUR WORK.

Descartes was obsessed with certainty. In his book Rules for the Direction of the Mind, “he sought to generalize the methods of mathematics so as to provide a route to clear knowledge of everything that human beings can know,” Hatfield writes. His advice included this classic chestnut: To solve a big problem, break it up into small, easy-to-understand parts—and check each step often.

9. HE LIKED TO HIDE.

Descartes had a motto, which he took from Ovid: “Who lives well hidden, lives well.” When he moved to the Netherlands, he regularly changed apartments and deliberately kept his address a secret. Some say it's because he simply desired privacy for his philosophical work, or that he was avoiding his disapproving family. In his book titled Descartes, philosopher A. C. Grayling makes another suggestion: "Descartes was a spy."

10. HE WASN'T AFRAID OF CRITICS. IN FACT, HE RE-PUBLISHED THEM.

When Descartes was revising his Meditations on First Philosophy [PDF], he planned to send the manuscript to “the 20 or 30 most learned theologians” for criticism—a sort of proto-peer review. He collected seven objections and published them in the work. (Descartes, of course, had the last word: He responded to each criticism.)

11. HE COULD THROW SHADE WITH THE BEST OF THEM.

In the 1640s, Descartes’s pupil and friend Henricus Regius published a broadsheet that distorted Descartes’s theory of the mind. (Which, put briefly, posits that the material body and immaterial mind are separate and distinct.) The two men had a falling out, and Descartes wrote a rebuttal with a barbed title that refused to even acknowledge Regius’s manifesto by name: It was simply called “Comments on a Certain Broadsheet.”

12. HE NEVER BELIEVED MONKEYS COULD TALK.

There’s a “fun fact” parading around that suggests Descartes believed monkeys and apes could talk. He believed no such thing. According to the Stanford Encyclopedia of Philosophy, Descartes denied that animals were even conscious, let alone capable of speech. The factoid comes from a misreading of a letter Descartes had written in 1646, in which he attributed the belief to “savages.”

13. HE TOTALLY HAD THE HOTS FOR CROSS-EYED WOMEN.

In a letter to Queen Christina of Sweden, Descartes explained that he had a cross-eyed playmate as a child. “I loved a girl of my own age ... who was slightly cross-eyed; by which means, the impression made in my brain when I looked at her wandering eyes was joined so much to that which also occurred when the passion of love moved me, that for a long time afterward, in seeing cross-eyed women, I felt more inclined to love them than others.”

14. WHEN HE MET BLAISE PASCAL, THEY GOT INTO AN ARGUMENT ... ABOUT VACUUMS.

In 1647, a 51-year-old Descartes visited the 24-year-old prodigy and physicist Blaise Pascal. Their meeting quickly devolved into a heated argument over the concept of a vacuum—that is, the idea that air pressure could ever be reduced to zero. (Descartes said it was impossible; Pascal disagreed.) Later, Descartes wrote a letter that, depending on your translation, said that Pascal had “too much vacuum in his head.”

15. HIS WORK WAS BANNED BY THE CATHOLIC CHURCH.

Back in the late 1630s, the theologian Gisbert Voetius had convinced the academic senate of the University of Utrecht to condemn the philosopher’s work. (Descartes was Catholic, but his suggestion that the universe began as a “chaotic soup of particles in motion,” in Hatfield's words, was contrary to orthodox theology.) In the 1660s, his works were placed on the church’s Index of Prohibited Books.

16. HE REGULARLY SLEPT UNTIL NOON (AND TRYING TO BREAK THE HABIT MIGHT HAVE KILLED HIM).

Descartes was not a morning person. He often snoozed 12 hours a night, from midnight until lunchtime. In fact, he worked in bed. (Sleep, he wisely wrote, was a time of “nourishment for the brain.”) But according to the Journal of Historical Neuroscience, he may have had a sleep disorder that helped end his life. A year before his death, Descartes had moved to Stockholm to take a job tutoring Queen Christina, a devoted early-riser who forced Descartes to change his sleep schedule. Some believe the resulting sleep deprivation weakened his immune system and eventually killed him.

17. HIS SKELETON HAS TRAVELED FAR AND WIDE.

Descartes died in Stockholm in 1650 and was buried outside the city. Sixteen years later, his corpse was exhumed and taken to Paris. During the French Revolution, his bones were moved to an Egyptian sarcophagus at the Museum of French Monuments. Decades later, when plans were made to rebury Descartes in an abbey, officials discovered that most of his bones—including his skull—were missing. Shortly after, a Swedish scientist discovered a newspaper advertisement attempting to sell the polymath’s noggin [PDF]. Today, his head is in a collection at the Musée de l’Homme in Paris.

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The Hidden Meanings Behind 11 Common Tombstone Symbols

Tombstone symbols can sometimes be hard to interpret.
Tombstone symbols can sometimes be hard to interpret.
Photo by Brett Sayles from Pexels

Walk through any cemetery in the world and you’ll find a solemn landscape that honors loved ones that have passed on. Accompanying the inscriptions of names, dates, and family crests are some common symbols that crop up repeatedly on tombstones. If you’ve ever wondered what they could mean, take a look at some of the explanations behind the graveyard graphics.

1. Eye

The eyes have it.Valerie Everett, Flickr // CC BY-SA 2.0

If you feel someone may be looking at you in the cemetery, you might be near a tombstone engraved with an eye. Often surrounded in a burst of sunlight or a triangle, an eye typically represents the all-seeing eye of God and could denote that the decedent was a Freemason.

2. Clasped Hands

Hands on a tombstone can mean several things.Christina Ramey, Flickr // CC BY-SA 2.0

Seeing two hands clasped together can illustrate shaking hands or holding hands, depending on the position of the thumbs. A handshake can mean a greeting to eternal life. If clasped hands have different cuffs, it could indicate a bond between the deceased and a spouse or relative. If one hand is higher than the other, it could also mean that a person is being welcomed by a loved one or a higher power. The hand engraving grew into wide use during the Victorian era.

3. Dove

Doves appear in a variety of poses on tombstones.Tim Green, Flickr // CC BY 2.0

A dove usually symbolizes peace and the Holy Spirit, but its specific meaning depends on how the bird is posed. If it’s flying upward, the soul is ascending to heaven. If it’s flying down, it represents the Holy Spirit arriving at the baptism of Jesus Christ. If it’s holding an olive branch in its mouth, it refers to an ancient Greek belief that olive branches could ward off evil spirits.

4. Broken Chain

Chains on tombstones can be linked or broken.Carl Wycoff, Flickr // CC BY 2.0

Medieval wisdom once held that a golden chain kept the soul in the body. In death, the chain is broken and the soul is freed. If the chain is unbroken and if it features the letters FLT (for Friendship, Love, and Truth), it probably means the deceased belonged to the Independent Order of Odd Fellows, a fraternal organization that seeks to promote charitable causes and offer aid.

5. Book

The meaning of a book on a tombstone isn't always easy to read.Carl Wycoff, Flickr // CC BY 2.0

Was the deceased an avid reader? Maybe, but not necessarily. An open book on a tombstone might refer to a sacred text like the Bible, the “book of life,” or the person’s willingness to learn. If you see a dog-earned corner on the right side, it could indicate the person’s life ended prematurely and before their “book” was finished.

6. Finger Pointing Up

An index finger pointing up can direct visitors to look up.Christina Ramey, Flickr // CC BY-SA 2.0

A hand with the index finger raised skyward is one of the more ambiguous symbols found in graveyards. It might be pointing to heaven, or indicate the fact that the decedent has risen from the land of the living.

7. Corn

Ears of corn could mean the deceased was a farmer.mike krzeszak, Flickr // CC BY 2.0

A corn stalk on a tombstone means the deceased could have been a farmer; it used to be a custom to send corn instead of floral arrangements to a farmer’s family. It might represent other kinds of grain. Alternately, corn seeds can symbolize rebirth.

8. Scroll

Scrolls on a tombstone can refer to an unknown future.Kelly Teague, Flickr // CC BY-SA 2.0

A scroll engraved on a tombstone with both ends rolled up can indicate that part of life has already unfolded while the future is hidden.

9. Lamp

Lamps can mean a love of knowledge.Sean, Flickr // CC BY-ND 2.0

A lamp on a tombstone could speak to a love of learning or knowledge, or it might refer to how the spirit is immortal.

10. Camel

Camels aren't something you'd expect to see on a tombstone.Glen, Flickr // CC BY 2.0

While this particular camel signifies the Imperial Camel Corps that occupied desert regions during World War I, a camel can also represent a long journey or a skilled guide—in this case, for the afterlife.

11. Hourglass

An hourglass can be a message to the living.justiny8s, Flickr // CC BY 2.0

As you may have guessed, the hourglass symbolizes the march of time. An hourglass on its end may mean the deceased died suddenly, while a winged hourglass communicates how quickly time flies. It may also be construed as a message to the living—time is short, so don’t waste it.