Stubborn and ardent clinging to one's opinion is the best proof of stupidity.

• Age imprints more wrinkles in the mind than it does on the face.
• There is no pleasure to me without communication: there is not so much as a sprightly thought comes into my mind that it does not grieve me to have produced alone, and that I have no one to tell it to.
• My trade and art is to live.
• Stubborn and ardent clinging to one's opinion is the best proof of stupidity.
• Let us permit nature to have her way. She understands her business better than we do.
• There is no pleasure to me without communication: there is not so much as a sprightly thought comes into my mind that it does not grieve me to have produced alone, and that I have no one to tell it to.
• No pleasure has any savor for me without communication.
• Valor is stability, not of legs and arms, but of courage and the soul.
• The strangest, most generous, and proudest of all virtues is true courage.
• It is not death, it is dying that alarms me.