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.

So act that anything you do may become universal law.

The arts of speech are rhetoric and poetry. Rhetoric is the art of transacting a serious business of the understanding as if it were a free play of the imagination; poetry that of conducting a free play of the imagination as if it were a serious business of the understanding.

Even a man's exact imitation of the song of the nightingale displeases us when we discover that it is a mimicry, and not the nightingale.

Enlightenment is man's leaving his self-caused immaturity. Immaturity is the incapacity to use one's intelligence without the guidance of another. Such immaturity is self-caused if it is not caused by lack of intelligence, but by lack of determination and courage to use one's intelligence without being guided by another. Sapere Aude! Have the courage to use your own intelligence! is therefore the motto of the enlightenment.

Happiness, though an indefinite concept, is the goal of all rational beings

Apart from moral conduct, all that man thinks himself able to do in order to become acceptable to God is mere superstition and religious folly.