How could the human mind progress, while tormented with frightful phantoms, and guided by men, interested in perpetuating its ignorance and fears? Man has been forced to vegetate in his primitive stupidity: he has been taught stories about invisible powers upon whom his happiness was supposed to depend. Occupied solely by his fears, and by unintelligible reveries, he has always been at the mercy of priests, who have reserved to themselves the right of thinking for him, and of directing his actions.

The source of man's unhappiness is his ignorance of Nature.

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?

Suns are extinguished or become corrupted, planets perish and scatter across the wastes of the sky; other suns are kindled, new planets formed to make their revolutions or describe new orbits, and man, an infinitely minute part of a globe which itself is only an imperceptible point in the immense whole, believes that the universe is made for himself.

People have suffered and become insane for centuries by the thought of eternal punishment after death. Wouldn't it be better to depend on blind matter... than a god who puts out traps for people, invites them to sin, and allows them to sin and commit crimes he could prevent. Only to finally get the barbarian pleasure to punish them in an excessive way, of no use for himself, without them changing their ways and without their example preventing others from committing crimes.

It is thus religion infatuates man from his infancy, fills him with vanity and fanaticism: if he has a heated imagination it drives him on to fury; if he has activity, it makes him a madman, who is frequently as cruel to himself, as he is dangerous and incommodious to others: if, on the contrary, he be phlegmatic or of a slothful habit, he becomes melancholy and is useless to society.

In Nature nothing; is mean or contemptible, and it is only pride, originating in a false idea of our superiority, which causes our contempt for some of her productions. In the eyes of Nature, however, the oyster that vegetates at the bottom of the sea is as dear and perfect as the proud biped who devours it.