Act as if the maxim of your action were to become through your will a be general natural law.

Happiness

It is not God's will merely that we should be happy, but that we should make ourselves happy

Instinct

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.

Philosophers and Philosophy

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 !. What may I hope?