Immanuel Kant

"Act only according to that maxim whereby you can at the same time will that it should become a universal law."

"Sapere aude! Dare to know! Have courage to use your own understanding."

"Two things awe me most, the starry sky above and the moral law within."

"Immaturity is the incapacity to use one's intelligence without guidance from another."

"Out of the crooked timber of humanity, no straight thing was ever made."

"The only thing that could be called good without qualification is a good will."

"I am never content to take your word for it. I do not believe it on authority."

"Duty! Thou sublime and mighty name."

"The existence of God is not provable by reason, but neither is it disprovable."

"Enlightenment is humanity's emergence from self-imposed immaturity."

"Space and time are not conditions of things in themselves, but conditions of our intuition of things."

"Man can become free only through love."

"What can I know? What should I do? What may I hope? What is man?"

"Treat humanity always as an end in itself, never merely as a means."

"The practical reason is the highest faculty of human beings."

"We cannot deny our reason without destroying our very nature."

"A categorical imperative would be one which represented an action as necessary of itself."

"The starry heavens fill me with wonder; the moral law fills me with awe."

"Happiness is not an ideal of reason but of imagination."

"Lying is a violation of duty to others; it is intrinsically wrong."

"Everything that happens has a cause; nothing occurs by chance."

"The human mind will never be satisfied with mere appearance."

"Freedom is the only unoriginated birthright of all humans."

"Patience is a virtue that allows all other virtues to take root."

"The desire for knowledge is the first step toward wisdom."

"Our duties toward ourselves are more fundamental than those toward others."

"Beauty is purposiveness without purpose."

"A kingdom of ends is possible only through moral law."

"The person who makes no mistakes makes no progress."

"All our knowledge begins with the senses, proceeds to the understanding."