“[To think for oneself] is the maxim of a reason never passive. The tendency to such passivity, and therefore to heteronomy of reason, is called prejudice; and the greatest prejudice of all is to represent nature as not subject to the rules that the understanding places at its basis by means of its own essential law, i.e. is superstition. Deliverance from superstition is called enlightenment; because although this name belongs to deliverance from prejudices in general, yet superstition especially (in sensu eminenti) deserves to be called a prejudice. For the blindness in which superstition places us, which it even imposes on us as an obligation, makes the need of being guided by others, and the consequent passive state of our reason, peculiarly noticeable.”

“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.”

“I had therefore to remove knowledge, in order to make room for belief.”

“It is beyond a doubt that all our knowledge begins with experience.”

“Religion is the recognition of all our duties as divine commands.”

“Immaturity is the incapacity to use one's intelligence without the guidance of another.”

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

“Happiness is not an ideal of reason, but of imagination.”

“Morality is not the doctrine of how we may make ourselves happy, but how we may make ourselves worthy of happiness.”

“To be is to do.”

“Even philosophers will praise war as ennobling mankind, forgetting the Greek who said: 'War is bad in that it begets more evil than it kills.'”