Men always fool themselves when they give up experience for systems born of the imagination. Man is the work of nature, he exists in nature, he is subject to its laws, he can not break free, he can not leave even in thought; it is in vain that his spirit wants to soar beyond the bounds of the visible world, he is always forced to return.

Savage and furious nations, perpetually at war, adore, under diverse names, some God, conformable to their ideas, that is to say, cruel, carnivorous, selfish, blood-thirsty.

The unhappiness of people is due to their ignorance of nature.

The universe, that vast assemblage of every thing that exists, presents only matter and motion: the whole offers to our contemplation, nothing but an immense, an uninterrupted succession of causes and effects.

Can theology give to the mind the ineffable boon of conceiving that which no man is in a capacity to comprehend? Can it procure to its agents the marvellous faculty of having precise ideas of a god composed of so many contradictory qualities?

If the ignorance of nature gave birth to gods, the knowledge of nature is calculated to destroy them.

Men always fool themselves when they give up experience for systems born of the imagination. Man is the work of nature, he exists in nature, he is subject to its laws, he can not break free, he can not leave even in thought; it is in vain that his spirit wants to soar beyond the bounds of the visible world, he is always forced to return.