Descartes opens by asserting that everyone is equally well endowed with reason. Following scholastic philosophy, he claims that we are essentially rational animals, and while we may differ with respect to our accidental, or non-essential, properties, we must all share the same form, or essential properties. Since we are all equally human, we must all be equally rational. People have different opinions and arrive at the truth with varying degrees of success not because some people are better equipped with reason than others but because different people apply their reason in different ways.
Descartes proposes to share a method that he discovered in his youth that he believes has helped him increase his knowledge to the greatest possible extent given his own limitations. While he does not feel his reason is any better than anyone else's he does feel he's discovered a very effective method of applying it. Some people may not find this method useful, but he proposes to put it forth not as a guideline that all must follow, but merely as a description of the path he has followed in the hope that some might similarly profit from it.
Because his method is so tied up with the manner in which he's lived, his account is of necessity autobiographical. He begins with his youth, growing up in one of the finest schools in Europe. The education he gained there, he was told, would provide him with certain knowledge of everything useful in life. But at the end of his education he only found himself riddled with doubts, feeling he'd learnt nothing but an awareness of his own ignorance. He had been a strong student at one of the finest schools in one of the most enlightened ages in history, so he doubts that his disappointment was a result of not learning this certain knowledge that he'd been promised. Rather, he suggests, there was no such knowledge to be learned.
He did not discard the works he had learned in school, but he resolved not to study any further. He lauds the virtues of studying ancient texts, fables, history, oratory, poetry, mathematics, morality, theology, philosophy, and the other sciences, but also explains why they do not prove ultimately satisfying. Too many texts from or about other times can distance one from one's own time, while oratory and poetry seem to rely on innate skill rather than careful study. He deeply admired mathematics, but did not perceive its higher uses since it was mostly applied in engineering. Morality was usually poorly reasoned and studying theology was not likely to unlock the secrets of heaven. Philosophy has been disputed over for millennia without any real agreements, and Descartes doubts that he could settle what the greatest minds of past generations have failed to achieve. Lastly, the sciences are built upon the premises of philosophy and so are as uncertain as their foundations.
Instead, Descartes decided to abandon his books and see what he could learn in traveling the world. He learnt that people have all sorts of different customs, and what might seem strange in his native France is well accepted in great nations abroad. This helped him to mistrust anything that he had learned simply through custom and example and to trust his reason above all. One day, Descartes resolved to pursue studies within himself rather than in the world, to look inward and see what he could dig out by means of his reason. In this study, he feels he has had far greater success than anything he has learned from books or traveling.
Descartes was educated at the Jesuit college of La Fleche—considered one of the finest schools of the age—from the age of ten to eighteen or nineteen. He then took a doctorate in law at the University of Poitiers. The travels he describes after his years of study took place mostly in Holland and Germany, serving in the armies of Maurice of Nassau and then Maximilian of Bavaria. He left France in 1618, at the age of twenty-two, and returned in 1622.