“Morality is not properly the doctrine of how we may make ourselves happy, but how we may make ourselves worthy of happiness.”
“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?”
“All thought must, directly or indirectly, by way of certain characters, relate ultimately to intuitions, and therefore, with us, to sensibility, because in no other way can an object be given to us.”
“Nothing is divine but what is agreeable to reason.”
“By a lie, a man...annihilates his dignity as a man.”
“What can I know? What ought I to do? What can I hope?”
“Live your life as though your every act were to become a universal law.”
“So act that your principle of action might safely be made a law for the whole world.”
“From such crooked wood as that which man is made of, nothing straight can be fashioned.”
“It is not God's will merely that we should be happy, but that we should make ourselves happy”
“Act as if the maxim of your action were to become through your will a be general natural law.”
“Out of timber so crooked as that from which man is made nothing entirely straight can be carved.”
“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.”
“Two things fill me with constantly increasing admiration and awe, the longer and more earnestly I reflect on them: the starry heavens without and the moral law within.”
“Intuition and concepts constitute... the elements of all our knowledge, so that neither concepts without an intuition in some way corresponding to them, nor intuition without concepts, can yield knowledge.”
“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.”