Live your life as though your every act were to become a universal law.
Immanuel Kant was a German philosopher who is a central figure in modern philosophy. Kant argues that the human mind creates the structure of human experience, that reason is the source of morality, that aesthetics arises from a faculty of disinterested judgment, that space and time are forms of human sensibility, and that the world as it is "in-itself" is independent of humanity's concepts of it. Kant took himself to have effected a "Copernican revolution" in philosophy, akin to Copernicus' reversal of the age-old belief that the sun revolves around the earth. Kant's beliefs continue to have a major influence on contemporary philosophy, especially the fields of metaphysics, epistemology, ethics, political theory, and aesthetics.