Descartes: Selected Philosophical Writings

of rightly conducting one's reason and seeking the truth in the sciences

If this discourse seems too long to be read at a sitting you may divide it into six parts. In the first you will find various considerations regarding the sciences; in the second, the principal rules of the method which the author has sought; in the third, some of the moral rules he has derived from this method; in the fourth, the arguments by which he proves the existence of God and the human soul, which are the foundations of his metaphysics; in the fifth, the order of the questions in physics that he has investigated and, in particular, the explanation of the movement of the heart and of some other difficulties pertaining to medicine, and also the difference between our soul and that of the beasts; and in the last, the things he believes necessary in order to make further progress in the investigation of nature than he has made, and the reasons which made him write this discourse.

PART ONE

Good sense is the best distributed thing in the world: for everyone thinks himself so well endowed with it that even those who are the hardest to please in everything else do not usually desire more of it than they possess. In this it is unlikely that everyone is mistaken. It indicates rather that the power of judging well and of distinguishing the true from the false - which is what we properly call 'good sense' or 'reason' - is naturally equal in all men, and consequently that the diversity of our opinions does not arise because some of us are more reasonable than others but solely because we direct our thoughts along different paths and do not attend to the same things.