René Descartes (1596-1650)
 

                            After receiving a sound education in mathematics,
                    classics, and law at La Flèche and Poitiers, René Descartes
                    embarked on a brief career in military service with Prince
                    Maurice in Holland and Bavaria. Unsatisfied with scholastic
                    philosophy and troubled by skepticism of the sort expounded
                    by Montaigne, Descartes soon conceived a comprehensive
                    plan for applying mathematical methods in order to achieve perfect certainty in
                    human knowledge. During a twenty-year period of secluded life in Holland, he
                    produced the body of work that secured his philosophical reputation. Descartes
                    moved to Sweden in 1649, but did not survive his first winter there.

                              Although he wrote extensively, Descartes chose not to publish his earliest
                    efforts at expressing the universal method and deriving its consequences. The
                    Regulae ad directionem ingenii (Rules for the Direction of the Mind) (1628)
                    contain his first full statement of the principles underlying the method and his
                    confidence in the success of their application. In Le Monde (The World) (1634),
                    Descartes clearly espoused a Copernican astronomy, but he withheld the book
                    from the public upon learning of Galileo's condemnation.

                              Descartes finally presented (in French) his rationalist vision of the progress of
                    human knowledge in the Discours de la méthode pour bien conduire sa Raison
                    et chercher la Vérité dans les Sciences   (Discourse on Method) (1637). In this
                    expository essay, Descartes assessed the deficient outcomes of a traditional
                    education, proposed a set of rules with which to make a new start, and described
                    the original experience upon which his hope for unifying human knowledge was
                    based. The final sections of the Discourse and the essays (on dipotric, meteors,
                    and geometry) appended to it illustrate the consequences of employing this method.

                              A few years later, Descartes offered (in Latin) a more formal exposition of
                    his central tenets in Meditationes de Prima Philosophia (Meditations on First
                    Philosophy) (1641). After an expanded statement of the method of doubt, he
                    argued that even the most dire skepticism is overcome by the certainty of one's
                    own existence as a thinking thing. From this beginning, he believed it possible to
                    use our clear and distinct ideas to demonstrate the existence of god, to establish the
                    reliability of our reason generally despite the possibility of error, to deduce the
                    essence of body, and to prove that material things do exist. On these grounds,
                    Descartes defended a strict dualism, according to which the mind and body are
                    wholly distinct, even though it seems evident that they interact. The Meditations
                    were published together with an extensive set of objections (by Hobbes, Gassendi,
                    Arnauld, and others) and Descartes's replies. Descartes later attempted a more
                    systematic exposition of his views in the Principia Philosophiae (Principles of
                    Philosophy) (1644) and an explanation of human emotion in Les Passions de
                    L'Ame (The Passions of the Soul).