To be is to do.
Immanuel Kant

What can I know? What ought I to do? What can I hope?
Immanuel Kant

It is beyond a doubt that all our knowledge that begins with experience.
Immanuel Kant

He who is cruel to animals becomes hard also in his dealings with men. We can judge the heart of a man by his treatment of animals.
Immanuel Kant

Always recognize that human individuals are ends, and do not use them as means to your end.
Immanuel Kant

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

All our knowledge begins with the senses, proceeds then to the understanding, and ends with reason. There is nothing higher than reason.
Immanuel Kant