"To be a good philosopher, one must be a good mathematician."

"The chief cause of human error is the confused nature of our perceptions."

"I am accustomed to take my sleep for granted, and I often imagine that I dream of the most important things, when after all I am only dreaming."

"It is a mark of a truly great mind to be able to make a great discovery with few means."

"The long chains of simple and easy reasonings by means of which geometers are accustomed to reach the conclusions of their most difficult demonstrations, had led me to imagine that all things, to the …"