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.
It is not God's will merely that we should be happy, but that we should make ourselves happy.
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 our knowledge begins with the senses, proceeds then to the understanding, and ends with reason. There is nothing higher than reason.
Act that your principle of action might safely be made a law for the whole world.
A categorical imperative would be one which represented an action as objectively necessary in itself, without reference to any other purpose.
By a lie, a man... annihilates his dignity as a man.
Thoughts without content are empty, intuitions without concepts are blind.
What can I know? What ought I to do? What can I hope?
The only objects of practical reason are therefore those of good and evil. For by the former is meant an object necessarily desired according to a principle of reason; by the latter one necessarily shunned, also according to a principle of reason.
So act that your principle of action might safely be made a law for the whole world.
Science is organized knowledge. Wisdom is organized life.
Live your life as though your every act were to become a universal law.
Out of timber so crooked as that from which man is made nothing entirely straight can be carved.
Metaphysics is a dark ocean without shores or lighthouse, strewn with many a philosophic wreck.