The most brilliant flashes of wit come from a clouded mind, as lightning leaps only from an obscure firmament.
Galileo called doubt the father of invention; it is certainly the pioneer.
The great artist is a slave to his ideals.
Courage enlarges, cowardice diminishes resources.
Enthusiasm is the inspiration of everything great. Without it no man is to be feared, and with it none despised.
Cheerfulness is an offshoot of goodness and of wisdom.