One of my favourite biographies is a life of Pepys by Claire Tomalin. Pepys lived in the 17th century and was a child during the English Civil War, of which Tomalin said something quite remarkable: the intellectual revolution accompanying it was so profound that it is difficult to understand how people thought before it occurred.
That remark was much in my mind as I read this new biography of Descartes, who also lived in the 17th century. It was a time when religion and science were closely linked, and science itself based upon the discoveries of the ancient Greeks, filtered through centuries of Scholastic thought.
People believed the sun revolved around the earth, and that angels, humans, and animals were linked in a “great chain of being.” There were four elements in the universe (earth, air, fire, and water), and four humours in the body (blood, phlegm, black bile, and yellow bile), the balancing of which was necessary to maintain good health. Vying with this traditional approach to knowledge was “a heady mixture of notions, beliefs and practices from cabalistic, occult, astrological, alchemical, hermetic and magical sources.”
Into this array of the hidebound and the bizarre stepped Descartes, whose great contribution to science was the assumption that "the natural world can be examined and understood as a system of matter in motion obeying natural laws, without the need for any invocation of supernatural forces or agencies."
He proposed to do this by jettisoning the past and starting anew, basing all science on what could be known for certain – hence his starting point, Cogito ergo sum. He promulgated this approach in his famous Discourse on Method, and applied it in his own investigation of the natural world, which included the grinding of his own lenses and the dissection of cadavers.
His Life
Descartes lived a rather adventurous life for an intellectual barely five feet tall. He spent several years wandering about the continent when it was embroiled in the Thirty Years War (1614-1648), which began as a religious conflict and devastated central Europe. He was, for a period, a mercenary, first joining the Protestant army of the Prince of Orange, and then the Catholic army of Maximilian of Bavaria. He was with the latter at the Battle of the White Mountain (near Prague) where the Protestant forces of Frederick of the Palatinate were routed. [Other sources have also placed him at the infamous siege of La Rochelle, where Cardinal Richelieu starved to death 20,000 Huguenots.]
The author of this bio, A.C. Grayling, has an interesting theory for why Descartes so often turned up in contentious areas in Europe. He may have been a Jesuit intelligence agent. Descartes was educated by Jesuits, who in turn encouraged the Habsburg rulers of the Holy Roman Empire to reclaim Catholic territories lost to Protestant forces during the Reformation.
If true, it may explain why Descartes spent the remaining portion of his life in the Protestant Netherlands. His pro-Habsburg Jesuit interests would not have endeared him to France, which had reasons of its own for opposing Habsburg ambitions. The need for caution was further underlined when in 1633 Galileo was tried for heresy by the Inquisition, and required to remain under house arrest for the remainder of his life. Descartes immediately abandoned plans to publish his masterwork, Le Monde, and changed residences frequently.
Whether or not Descartes was a spy, it was a good time to be in the Netherlands, which was not only wealthy and tolerant, but also enjoying the Dutch Golden Age. Descartes wrote all of his major works there, and shared with Rembrandt the patronage of Christiaan Huygens's father. It was there he met Princess Elizabeth of Bohemia, with whom he struck up a close intellectual relationship.
When he finally did venture back to France, he supped with Thomas Hobbes and met Blaise Pascal, who showed him the calculating machine he had made (“the first ever computer, based on the technology of knitting machines”). Improbably his life came to an end in Sweden, where he was enticed by Queen Christina to serve as her personal tutor.
Grayling points out several ironies here. Princess Elizabeth was the daughter of Frederick, the Elector Palatine, whom Descartes helped to overthrow at the Battle of the White Mountain. Christina of Sweden was her cousin, and daughter of the great Gustavus Adolphus, who brought Sweden into the Thirty Years War on the Protestant side. Christina was instrumental in ending the war, and after Descartes died she abdicated and converted to Catholicism.
His Legacy
Many of Descartes’s scientific notions were wrong. Indeed, some of them sound as unlikely as other crackpot ideas of the time. He believed that the pineal gland was the seat of the soul, that the motion of the planets is explained by vortices in a universal fluid, and that vision results from "pressure on the eye" by that fluid.
Despite these missteps, Descartes is today considered the “Father of Modern Philosophy.” Among other achievements he discovered the law of refraction and created analytic geometry, which is taught in high schools today. His Discourse on Method is one of the seminal texts of the modern world. After four centuries the book is still in print and taught in universities around the world.
