Descartes

67. To a strong man, physically prepared for it, doubt liberates and strengthens. Doubt shatters the world so that he must rebuild it, must make decisions on how it is reengineered. It is a daunting task, and few men have the courage to doubt deeply enough and fewer still the strength for the rebuilding.

70. Descartes is exemplary of a doubt that cripples and sickens a weak and fearful man. Descartes doubted everything but then wanted his world to be exactly as it was before the doubts appeared. His fear of losing his world, his God, his comfortable life, led him to ridiculous flights of thinking to keep his world intact.

72. But an honest, strong, courageous man will doubt so deeply that the world is shattered and then he will rebuild it without regard to the whims of other men, or even his own security. If there is no place for God, then there is no place for Him. Perhaps there is no place for him either. So be it. But great efforts begin in great doubt.

77. Even worse than writing philosophy while sitting is writing it while lying down.