We find that the more a cultivated reason devotes itself to the aim of enjoying life and happiness, the further does man get away from true contentment.

For how is it possible, says that acute man, that when a concept is given me, I can go beyond it and connect with it another which is not contained in it, in such a manner as if that latter necessarily belonged to the former?

Ingratitude is the essence of vileness.

Out of the crooked timber of humanity, no straight thing was ever made.

Enlightenment is the liberation of man from his self-caused state of minority... Supere aude! Dare to use your own understanding!is thus the motto of the Enlightenment.

The ultimate destiny of the human race is the greatest moral perfection, provided that it is achieved through human freedom, whereby alone man is capable of the greatest happiness.

There is something splendid about innocence; but what is bad about it, in turn, is that it cannot protect itself very well and is easily seduced.