Rene Descartes 1596-1650 Rene Descartes 1596-1650

Criterion of Certainty:At the beginning of Meditation III Descartes come to a criterion of certainty:By examining the truths which he discovered in the course of his second meditation, hedecides that all of them have in common the proper ties of being clear and distinct.Therefore:"So, I now seem to be able to lay it down as a general rule that whatever I perceive veryclearly and distinctly is true."He notes an objection to this claim, which is that he had previously accepted as evidentthings which turned out to be doubtful.For example he saw the earth, the sky and the stars with the senses-clearly and distinctly. Heargues that what he in fact saw were the ideas of such things, and that he assumed withoutgood reason that there were things in the external world which caused such ideas. Thisreflection again adds to the store of things which Descartes knows for certain, for now thereare all of those ideas which clearly and distinctly appear before the mind. The only becomeswhether anything corresponds to and causes them.77