The eternal mystery of the world is its comprehensibility.
Always recognize that human individuals are ends, and do not use them as means to your end.
Experience without theory is blind, but theory without experience is mere intellectual play.
To be is to do.
Happiness is not an ideal of reason, but of imagination.
Metaphysics is a dark ocean without shores or lighthouse, strewn with many a philosophic wreck.
It is not God's will merely that we should be happy, but that we should make ourselves happy.
Intuition and concepts constitute the elements of all our knowledge, so that neither concepts without an intuition in some way corresponding to them, nor intuition without concepts, can yield knowledge.
Two things fill the mind with ever new and increasing wonder and awe: the starry heavens 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.