Live your life as though your every act were to become a universal law.
Act in such a way that you treat humanity, whether in your own person or in the person of any other, never merely as a means to an end, but always at the same time as an end.
Out of timber so crooked as that from which man is made nothing entirely straight can be carved.
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?
By a lie, a man... annihilates his dignity as a man.
Thoughts without content are empty, intuitions without concepts are blind.
Nothing is divine but what is agreeable to reason.
Have patience awhile slanders are not long-lived. Truth is the child of time erelong she shall appear to vindicate thee.
A categorical imperative would be one which represented an action as objectively necessary in itself, without reference to any other purpose.
Seek not the favor of the multitude; it is seldom got by honest and lawful means. But seek the testimony of few; and number not voices, but weigh them.
Morality is not the doctrine of how we may make ourselves happy, but how we may make ourselves worthy of happiness.
Freedom is independence of the compulsory will of another.