[A ruler is merely] the trustee of the rights of other men and he must always stand in dread of having in some way violated these rights.

Natural science physics contains in itself synthetical judgments a priori, as principles. ... Space then is a necessary representation a priori, which serves for the foundation of all external intuitions.

Most men use their knowledge only under guidance from others because they lack the courage to think independently using their own reasoning abilities. It takes intellectual daring to discover the truth.

Art does not want the representation of a beautiful thing, but the representation of something beautiful.

In the mere concept of one thing it cannot be found any character of its existence.

If you punish a child for being naughty, and reward him for being good, he will do right merely for the sake of the reward; and when he goes out into the world and finds that goodness is not always rewarded, nor wickedness always punished, he will grow into a man who only thinks about how he may get on in the world, and does right or wrong according as he finds advantage to himself.

Philosophy stands in need of a science which shall determine the possibility, principles, and extent of human knowledge à priori.