John Sutton, December 1999

According to Rene Descartes, the great French natural philosopher, memories are not fixed items permanently written into our brains. Instead, memories are motions, the flow of nervous fluids and animal spirits through the folds of the brain, or in a musician's hands.

Descartes died in 1650, at the age of 53. A lifetime habit of staying in bed till noon had been disrupted by a move to Stockholm. His new patron Queen Christina was celebrating the end of the Thirty Years' War. She wanted her philosophy lessons at five o'clock in the morning, and in the long Swedish winter Descartes contracted pneumonia. This amused his theological opponents, because Descartes had hoped that advances in medical theory would allow him to live more than a hundred years.

At the end of the millennium we usually remember Descartes as the 'father of modern philosophy'. Isn't he the dualist who separated mind from body? We are meant to trust Descartes when he tells us to throw our books away, to be suspicious of authority, to educate ourselves afresh. By tearing down the house of traditional belief, Descartes recommends, we can construct new and certain foundations on which to build up our knowledge.

But Descartes also knew that no-one can choose to forget, that we can't just blissfully escape our origins, or the limitations of our time. We are all marked by memory, by history. And Descartes advised his correspondents, like Princess Elizabeth of Bohemia, not to spend too much time in deep metaphysical speculations. Observation and imagination, in the midst of life, are more important than thinking.

In Amsterdam Descartes dissected the heads of various animals in order to explain memory and imagination. Beasts are machines, living statues driven only by the complex organization of their organs. It sounds like the death of nature, the technological urge to master and possess. Geometry and violence.

But in Descartes' fables, these automata are self-moving machines which dream, eat, remember, feel. Our bodies too are full of fluids, full of animal spirits which never stop in any place. As in the whirling vortices which compose the cosmos, the fluids inside us circulate endlessly. What seems to be solid is really fluid. What seems to be empty is really full.

So how does memory work? For Descartes, there are no little images, pictures of the past somehow stored inside our skulls. Life's marks are not indelible, to be recollected later at will. Our experiences only bend, rearrange, and refold the fibres of the brain through which nervous fluids trace their paths. The pineal gland in the centre of the brain sways and dances on its network of arteries. It drives the rushing animal spirits down the particular pores which happen to hold our flickering memory traces.

Descartes' daughter, Francine, was conceived in Amsterdam on a Sunday, in October 1634. Her mother Helene was a maid in the household. He was studying the formation of the foetus. Was Francine just an experiment, nothing more? He called her his niece.

Hair turns white. Even machines decay. Once set in motion, Descartes knew, bodies move themselves. Some things won't stay still to be measured. Memories churn away, beyond conscious control. So it's not easy to live well. Morality is a change of habit: we must learn our own bodies and their games, applying intelligence to the reflexes.

Why love one person, not another? As a boy, Descartes loved a little girl who had a slight squint. As he later wrote, in the folds of memory, his traces mixed cross-eyes and love. The streams of animal spirits fused in his brain. This, he explained, was why he had always desired cross-eyed women without knowing why. But on realising that this was a trick of memory, a mere habit of the brain, the desire disappeared. So, maybe, you can control your own brain?

Death, according to Descartes, is not due to the soul leaving the body. Death is only the decay of the organs.

He planned to bring his daughter to France in late 1640, to give her a good education. But Francine died of scarlet fever, in September, on the third day of her illness, her five-year-old body completely covered with sores. Descartes said it was the greatest sorrow of his life. You can't just decide to forget.

Previous piece: The Arts of Memory.
Next piece: Animal Spirits.

Last updated 28 May 2000.