I did not imitate the skeptics who doubt only for doubting's sake, and pretend to be always undecided; on the contrary, my whole intention was to arrive at a certainty, and to dig away the drift and the sand until I reached the rock or the clay beneath.
Rene DescartesThere is a great difference between mind and body insomuch as body is by nature always divisible, and the mind is entirely indivisible.
Rene DescartesBut I cannot forget that, at other times I have been deceived in sleep by similar illusions; and, attentively considering those cases, I perceive so clearly that there exist no certain marks by which the state of waking can ever be distinguished from sleep, that I feel greatly astonished; and in amazement I almost persuade myself that I am now dreaming.
Rene DescartesThe greatest minds are capable of the greatest vices as well as of the greatest virtues.
Rene Descartes