Quote by Rene Descartes (1596-1650)

• I think; therefore I am.

• The only secure knowledge is that I exist.

• If you would be a real seeker after truth, it is necessary that at least once in your life you doubt, as far as possible, all things.

• The greatest minds are capable of the greatest vices as well as of the greatest virtues.

• I am a thing that thinks, that is to say, a thing that doubts, affrims, denies, understands a few things, is ignorant of many things, wills, refrains from willing, and also imagines and senses.

• It is not enough to have a good mind. The main thing is to use it well.