ABSTRACT
Descartes's father was a councillor of the Parlement of Brittany and possessed a moderate amount of landed property. In mechanics, Descartes accepts the first law of motion, according to which a body left to itself will move with constant velocity in a straight line. Descartes's proofs of the existence of God are not very original; in the main they come from scholastic philosophy. The method of critical doubt, though Descartes himself applied it only half-heartedly, was of great philosophic importance. Descartes himself allowed small exception: a human soul could, by volition, alter the direction though not the quantity of the motion of the vital spirits. Descartes was a philosopher, a mathematician, and a man of science. In philosophy and mathematics, his work was of supreme importance; in science, though creditable, it was not so good as that of some of his contemporaries.
