The worst is that the very hardest thinking will not bring thoughts. They must come like good children of God and cry, "Here we are." You expend effort and energy thinking hard. Then, after you have given up, they come sauntering in with their hands in their pockets. If the effort had not been made to open the door, however, who knows when they could have come.

He who has art and science also has religion, but those who do not have them better have religion.

Mathematicians are like Frenchmen: whatever you say to them they translate into their own language and forthwith it is something entirely different.

Doubt grows with knowledge.

[W]hat counts is that one perceives excellence and dares to give it expression, which sounds little but is in fact a great deal.

Words express neither objects nor ourselves.

A person hears only what they understand.