An action, to have moral worth, must be done from duty.

Heaven has given human beings three things to balance the odds of life: hope, sleep, and laughter.

Man desired concord; but nature knows better what is good for his species; she desires discord. Man wants to live easy and content; but nature compels him to leave ease... and throw himself into roils and labors.

Ours is an age of criticism, to which everything must be subjected. The sacredness of religion, and the authority of legislation, are by many regarded as grounds for exemption from the examination by this tribunal, But, if they are exempted, and cannot lay claim to sincere respect, which reason accords only to that which has stood the test of a free and public examination.

If justice perishes, human life on Earth has lost its meaning.

Act so as to use humanity, yourself and others, always as an end and never as a means to an end.

Freedom in the practical sense is the independence of the power of choice from necessitation by impulses of sensibility