Live your life as though your every act were to become a universal law.

Experience without theory is blind, but theory without experience is mere intellectual play.

Marriage...is the union of two people of different sexes with a view to the mutual possession of each other's sexual attributes for the duration of their lives.

Human reason has the peculiar fate in one species of its cognitions that it is burdened with questions which it cannot dismiss, since they are given to it as problems by the nature of reason itself, but which it also cannot answer, since they transcend every capacity of human reason.

All the interests of my reason, speculative as well as practical, combine in the three following questions: 1. What can I know? 2. What ought I to do? 3. What may I hope?

The wise man can change his mind; the stubborn one, never.

If man makes himself a worm he must not complain when he is trodden on.