I assert that, in any particular natural science, one encounters genuine scientific substance only to the extent that mathematics is present.

An action is essentially good if the motive of the agent be good, regardless of the consequences.

All our knowledge begins with the senses, proceeds then to the understanding, and ends with reason. There is nothing higher than reason.

One who makes himself a worm cannot complain afterwards if people step on him.

Each according to his own way of seeing things, seek one goal, that is gratification.

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.

Man's duty is to improve himself; to cultivate his mind; and, when he finds himself going astray, to bring the moral law to bear upon himself.