While the great philosophical distinction between mind and body in western thought can be traced to the Greeks, it is to the seminal work of Ren Descartes (1596-1650) [see figure 1], French mathematician, philosopher, and physiologist, that we owe the first systematic account of the mind / body relationship. Descartes was born in Touraine, in the small town of La Haye and educated from the age of eight at the Jesuit college of La Flche. At La Flche, Descartes formed the habit of spending the morning in bed, engaged in systematic meditation. During his meditations, he was struck by the sharp contrast between the certainty of mathematics and the controversial nature of philosophy, and came to believe that the sciences could be made to yield results as certain as those of mathematics. From 1612, when he left La Flche, until 1628, when he settled in Holland, Descartes spent much of his time in travel, contemplation, and correspondence. From 1628 until his ill-fated trip to Sweden in 1649 he remained for the most part in Holland, and it was during this period that he composed a series of works that set the agenda for all later students of mind and body.

The first of these works, De hominem [1] was completed in Holland about 1633, on the eve of the condemnation of Galileo. When Descartes' friend and frequent correspondent, Marin Mersenne, wrote to him of Galileo's fate at the hands of the Inquisition, Descartes immediately suppressed his own treatise. As a result, the world's first extended essay on physiological psychology was published only well after its author's death. The year 1641 saw the appearance of Descartes' Meditations de prima philosophic, in qui bus Dei existential, & animal corpor e distinction, demonstrator In 1649, on the eve of his departure for Stockholm to take up residence as instructor to Queen Christina of Sweden, Descartes sent the manuscript of the last of his great works Les passions de l'ame[3], to press.

Les passions is Descartes' most important contribution to psychology proper.