Nothing is divine but what is agreeable to reason.

Enlightenment is the liberation of man from his self-caused state of minority... Supere aude! Dare to use your own understanding!is thus the motto of the Enlightenment.

Suicide is not abominable because God prohibits it; God prohibits it because it is abominable.

In man (as the only rational creature on earth) those natural capacities which are directed to the use of his reason are to be fully developed only in the race, not in the individual.

Parents usually educate their children merely in such a manner than however bad the world may be, they may adapt themselves to its present conditions. But they ought to give them an education so much better than this, that a better condition of things may thereby be brought about by the future.

The enjoyment of power inevitably corrupts the judgment of reason, and perverts its liberty.

The more we come in contact with animals and observe their behaviour, the more we love them, for we see how great is their care of the young.