Divide each difficulty into as many parts as is feasible and necessary to resolve it. - René Descartes

Those in whom the faculty of reason is predominant, and who most skillfully dispose their thoughts with a view to render them clear and intelligible, are always the best able to persuade others of the truth of what they lay down, though they should speak only in the language of Lower Brittany, and be wholly ignorant of the rules of rhetoric; and those whose minds are stored with the most agreeable fancies, and who can give expression to them with the greatest embellishment and harmony, are still the best poets, though unacquainted with the art of poetry.

Αν όμως αφιερώνει κανείς πολύ χρόνο στα ταξίδια, τελικά αποξενώνεται από την ίδια του τη χώρα και όταν έχει υπερβολική περιέργεια για όσα συνηθίζονταν στους προηγούμενους αιώνες, συχνά έχει μεγάλη άγνοια για όσα συνηθίζονται σε αυτόν εδώ τον αιώνα.

El esquema de la demostración es el siguiente: la existencia es una perfección; Dios tiene todas las perfecciones; luego Dios tiene la existencia. Como se ve, Descartes considera la existencia de Dios tan segura y evidentemente demostrada como la propiedad del triángulo de tener tres ángulos.