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.
Two things awe me most, the starry sky above me and the moral law within me.
Ingratitude is the essence of vileness.
Act that your principle of action might safely be made a law for the whole world.
Metaphysics is a dark ocean without shores or lighthouse, strewn with many a philosophic wreck.
Always recognize that human individuals are ends, and do not use them as means to your end.