There is only one morality, as there is only one geometry.

Nothing can be more contrary to religion and the clergy than reason and common sense.

Pleasantry is never good on serious points, because it always regards subjects in that point of view in which it is not the purpose to consider them.

The most amazing and effective inventions are not those which do most honour to the human genius.

He who can lead you to believe an absurdity can lead you to commit an atrocity.

Monsieur l'abbé, I detest what you write, but I would give my life to make it possible for you to continue to write.

Men appear to prefer ruining one another's fortunes, and cutting each other's throats about a few paltry villages, to extending the grand means of human happiness.