Rene Descartes Being Thought Of 400 Years After Birth

PARIS - Cogito, ergo sum. "I think, therefore I am."

Four hundred years after Rene Descartes was born, it's a common phrase explaining rational thought as humankind's defining characteristic. When the 17th century French philosopher penned those words, it was revolutionary.

Symposiums, books, plays, exhibits, concerts and a commemorative stamp are planned this year to honor the great philosopher, mathematician and scientist born March 31, 1596.

Those celebrations range from Alain Simon's one-man-show dramatizing Descartes' "Discourse on Method"; to an essay contest for students around the philosopher's hometown of La Haye, rechristened Descartes in 1967; to a "Philosophy Night" in Poitiers, where residents will prove they exist, pontificating in cafes around the city.

Considered the founder of modern philosophy, Descartes went beyond the medieval focus on faith and established rational thought as the starting point for all reflection.

`A philosophy of common sense'

It was, according to contemporary French philosopher Andre Glucksmann, "a philosophy of common sense."

Much admired by his contemporaries, Descartes' multifaceted works left a lasting influence on generations of philosophers, including Voltaire, who said that Descartes gave sight to the blind.

Descartes is remembered for his "Cartesian doubt" and "Cartesian logic," a method that seeks to explain matter through a so-called objective search for reliable evidence leading to a conclusion.

For Descartes, body and mind were separate entities - like two parallel but independent clocks ticking at the same time.

Now, however, the adjective `Cartesian' has come to have some negative connotations.

"For some, `Cartesian' means stiff, while for others it means downright conservative or petit-bourgeois," wrote Francois Azouvi in the daily Le Monde. "In any case, for everybody it means `French.' "

Other philosophers point to Descartes' gifts.

"One of Descartes' greatest legacies was his insistence on evidence, clarity and the necessity of doubt before any real certainty can be acquired," said Jean-Jacques Demorest, historian and professor emeritus at the University of Arizona.

"Descartes also established the notion of modern science as we know it today, with the emphasis on research and reliable evidence as essential in the quest for truth," Demorest said in a telephone interview.

Huge contribution to math

Though his name is plastered on streets, schools and public buildings all over France, few non-mathematicians know that Descartes also made major contributions to geometry, algebra and calculus. Thanks to his notion of coordinates, forms and shapes can be mathematically represented.

"The impact of his reasoning was felt in all disciplines hinging on math - physics, chemistry, economics, engineering and biology," said Chaim Levendel, a mathematician and computer engineer based in Chicago.

The son of a low-ranked nobleman, Descartes was born in the village of La Haye in the Loire Valley. He studied at a prestigious Jesuit school and participated in celebrations of Galileo's discovery of Jupiter's moons in 1611.

Fame came early. In Paris, he was a celebrity, harassed and interrupted by visitors from around the world. Fleeing the hubbub, he spent most of his life in Holland.

"Descartes would work in bed, never emerging until noon, but the Parisian socialites would just barge in on him," Demorest said. "He was a real curiosity."

Descartes was in contact with the great scientific minds of his day and traveled extensively. He spent most of his time in arduous meditation, to "learn to distinguish the true from the false," as he put it in his famed "Discourse On Method" in 1637.

Though lambasted as inciting atheism, Descartes was not anti-religious and in fact believed a higher being existed to keep man on the straight and narrow.

Queen Christina of Sweden, who insisted he become her private tutor, was his undoing.

Descartes suffered from Stockholm's bitter cold and the long hours (lessons began at 5 a.m.). He died of pneumonia in 1650 at 54.

Even in death, everyone wanted a piece of him.

His mutilated body was finally buried in 1819 at the church of Saint Germain-des-Pres in Paris, while his head was donated later to the Musee de l'Homme.