All religious notions are uniformly founded on authority; all the religions of the world forbid examination, and are not disposed that men should reason upon them.

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?

Nature, you say, is totally inexplicable without a God. That is to say, to explain what you understand very little, you have need of a cause which you understand not at all.

All religions are ancient monuments to superstition, ignorance and ferocity.

These principles, universally recognized, are at fault when the question of the existence of God is considered; what has been said of Him is either unintelligible or perfectly contradictory; and for this reason must appear impossible to every man.

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

When we examine the opinions of men, we find that nothing is more uncommon, than common sense; or, in other words, they lack judgment to discover plain truths, or to reject absurdities, and palpable contradictions.