Riches ennoble a man's circumstances, but not himself.

It is by his activities and not by enjoyment that man feels he is alive. In idleness we not only feel that life is fleeting, but we also feel lifeless.

Animals... are there merely as a means to an end. That end is man.

Freedom is the alone unoriginated birthright of man, and belongs to him by force of his humanity; and is independence on the will and co-action of every other in so far as this consists with every other person's freedom.

If a man is often the subject of conversation he soon becomes the subject of criticism.

Nature has willed that man should, by himself, produce everything that goes beyond the mechanical ordering of his animal existence, and that he should partake of no other happiness or perfection than that which he himself, independently of instinct, has created by his own reason.

Two things strike me dumb: the infinite starry heavens, and the sense of right and wrong in man.

Man relates to material things through direct insight rather than reason.

[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.