In proportion as we endeavor to live according to the guidance of reason, shall we strive as much as possible to depend less on hope, to liberate ourselves from fear, to rule fortune, and to direct our actions by the sure counsels of reason.

Hatred is increased by being reciprocated, and can on the other hand be destroyed by love.

Anyone who seeks for the true causes of miracles, and strives to understand natural phenomena as an intelligent being, and not to gaze at them like a fool, is set down and denounced as an impious heretic.

The most tyrannical of governments are those which make crimes of opinions, for everyone has an inalienable right to his thoughts.

The more a government strives to curtail freedom of speech, the more obstinately is it resisted; not indeed by the avaricious, ... but by those whom good education, sound morality, and virtue have rendered more free.

Sin cannot be conceived in a natural state, but only in a civil state, where it is decreed by common consent what is good or bad.

Superstition, then, is engendered, preserved, and fostered by fear.