“An age cannot bind itself and ordain to put the succeeding one into such a condition that it cannot extend its (at best very occasional) knowledge , purify itself of errors, and progress in general enlightenment. That would be a crime against human nature, the proper destination of which lies precisely in this progress and the descendants would be fully justified in rejecting those decrees as having been made in an unwarranted and malicious manner.The touchstone of everything that can be concluded as a law for a people lies in the question whether the people could have imposed such a law on itself.”

“One age cannot bind itself, and thus conspire, to place a succeeding one in a condition whereby it would be impossible for the later age to expand its knowledge (particularly where it is so very important), to rid itself of errors, and generally to increase its enlightenment. That would be a crime against human nature, whose essential destiny lies precisely in such progress; subsequent generations are thus completely justified in dismissing such agreements as unauthorized and criminal. The criterion of everything that can be agreed upon as a law by a people lies in this question: Can a people impose such a law on itself?”

“All rational knowledge is either material, and concerns some objects, or formal, and is occupied only with the form of understanding and reason itself and with the universal rules of thinking, without regard to distinctions among objects. formal philosophy is called logic. Material philosophy, however, which has to do with definite object objects and the laws to which they are subject, is divided into two parts. This is because these laws are either laws of nature or laws of freedom. The science of the former is called physics, and that of the latter ethics. The former is also called theory of nature and the latter theory of morals.”

“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.”

“Enlightenment is man's emergence from his self-imposed nonage. Nonage is the inability to use one's own understanding without another's guidance. This nonage is self-imposed if its cause lies not in lack of understanding but in indecision and lack of courage to use one's own mind without another's guidance. Dare to know! (Sapere aude.) "Have the courage to use your own understanding," is therefore the motto of the enlightenment.”

“A categorical imperative would be one which represented an action as objectively necessary in itself, without reference to any other purpose.”

“True politics cannot take a single step without first paying homage to morals, and while politics itself is a difficult art, its combination with morals is no art at all; for morals cuts the Gordian knot which politics cannot solve as soon as the two are in conflict.”