Reason tries historical religion by the standard furnished by natural religion, and distinguishes actual from asserted revelation by the harmony of its contents with reason: the deist believes in the Bible because of the reasonableness of its teachings; he does not hold these teachings true because they are found in the Bible.

If the moralist distinguishes between actions that are evil because they are forbidden, and those that are forbidden because they are evil, the libertine has a counter-distinction between those that are forbidden because they are pleasant, and those that are pleasant because they are forbidden.