No single thinker has had a more decisive influence on the course of modern philosophy - and general intellectual inquiry - than Rene Descartes (1596-1650). On the 400th anniversary of Descartes's birth, Anthony Grafton considers the forces that shaped the man and his thought.
All philosophers have theories. Good philosophers have students and critics. But great philosophers have primal scenes. They play the starring roles in striking stories, which their disciples and later writers tell and retell, over the decades and even the centuries. Thales, whom the Greeks remembered as their first philosopher, tumbled into a well while looking up at the night sky, to the accompanying mockery of a serving maid. His example showed, more clearly than any argument could, that philosophy served no practical purpose. Those who take a different view of philosophy can cite a contrasting anecdote, also ancient, in their support: after drawing on his knowledge of nature to predict an abundant harvest, Thales rented out all the olive presses in Miletus and Chios. He made a fortune charging high rates for them; better still, he showed that scholar rhymes with dollar after all.
At the other end of Western history, in the 20th century, Ludwig Wittgenstein held that propositions are, in some way, pictures of the world: that they must have the same "logical form" as what they describe. He did so, at least, until he took a train ride one day with Piero Sraffa, an Italian economist at Cambridge. Making a characteristic Italian gesture, drawing his hand across his throat, Sraffa asked, "What is the logical form of that?" He thus set his friend off on what became the vastly influential Philosophical Investigations, that fascinating, endlessly puzzling text which the American philosophers of my youth took as their bible, and to the exegesis of which they brought a ferocious cleverness that would do credit to any seminarian. If Helen's face launched a thousand ships, Sraffa's gesture launched at least a hundred careers.
In each case - and in dozens of others - the story has passed from books to lectures to articles and back, becoming as smooth and shiny in the process as a pebble carried along by a swift-flowing stream. In fact, these stories have become talismans of sorts: evidence that the most profound ideas, the most rigorous analyses, have their origins in curious, human circumstances and strange, all-too-human people. Such anecdotes accessibly dramatize the heroic originality and rigor of philosophers - qualities that one cannot always appreciate only by studying their texts, slowly and carefully.
It seems appropriate, then, that no philosopher in the Western tradition has left a more fascinating - or more puzzling - trail of anecdote behind him than the Frenchman Rene Descartes. Like Wittgenstein's philosophy, Descartes's began from curious experiences; but in his case the provocation was - or was remembered as - nothing so banal as a train ride.
Early in his life, Descartes became a soldier, serving two years in the Dutch army, before joining the Bavarian service. He writes that in the late fall of 1619, while stationed in the German city of Ulm, he "was detained by the onset of winter in quarters where, having neither conversation to divert me nor, fortunately, cares or passions to trouble me, I was completely free to consider my own thoughts." He refused all company, went on solitary walks, and dedicated himself to an exhausting search for . . . he did not quite know what. Suddenly he stumbled on what he called "the foundations of a marvellous science." After an almost mystical experience of deep joy, Descartes fell asleep, in his close, stove-heated room. He then dreamed, three times.
In the first dream, terrible phantoms surrounded him. His efforts to fight them off were hindered by a weakness in his right side, which made him stagger in a way that struck him as terribly humiliating. Trying to reach a chapel that belonged to a college, he found himself pinned to the wall by the wind - only to be addressed by someone who called him by name, promising that one "M. …