Two things awe me most, the starry sky above me and the moral law within me.
In law a man is guilty when he violates the rights of others. In ethics he is guilty if he only thinks of doing so.
Metaphysics is a dark ocean without shores or lighthouse, strewn with many a philosophic wreck.
Live your life as though your every act were to become a universal law.
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.
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.