Rene Descartes is often considered the founding father of modern philosophy. A true Renaissance man, he studied Scholastic philosophy and physics as a student, spent time as a volunteer soldier and traveler throughout Europe, studied mathematics, appreciated the arts, and became a noted correspondent with royals and intellectual figures throughout the continent. He died in Sweden while on assignment as tutor to the Queen, Christiana.
Descartes 'Discourse on Method' is a fascinating text, combining the newly-invented form of essay (Descartes was familiar with the Essays of Montaigne) with the same kind of autobiographical impulse that underpins Augustine's Confessions. Descartes writes about his own form of mystical experience, seeing this as almost a kind of revelation that all past knowledge would be superseded, and all problems would eventually be solved by human intellect.
In the Discourse, Descartes formulates logical principles based on reason (which makes it somewhat ironic that this came to him almost as a revelation). Descartes had some appreciation for thinkers such as Francis Bacon and Thomas Hobbes, but he thought that Bacon depended too much upon empirical data, and with Hobbes he disagreed on what would be the criteria for ascertaining certainty.
Descartes was a mathematician at heart, and perhaps had a carry-over of Pythagorean mystical attachment to mathematics, for his sense of reason led him to impute an absolute quality to mathematics; this has major implications for metaphysics and epistemology. Descartes method was a continuation in many ways of the ideas of Plato, Aristotle and the medieval thinkers, for they all tended toward thinking in absolute, universal terms in some degree.
Descartes in his first section discounts much of Scholasticism, stating that the only real absolutes are theology and mathematics; because theology is based upon revelation, it is therefore beyond reason, and thus, mathematics becomes the only rational truth. Descartes develops this idea further with rules of method, which include ideas of intuition, analysis and deduction. He uses some of his method to come up with his greatest proposition:
Cogito ergo sum - - I think, therefore I am
'The Cogito is a first principle from which Descartes will now deduce all that follows.' This permits Descartes to deal both with rational elements and empirical data.
This is an important text, one that I read the summer before I went to college, and makes a good study for those who wish to see the personal element in the development of philosophy.