Love is nothing but joy accompanied with the idea of an eternal cause.

In regard to intellect and true virtue, every nation is on a par with the rest, and God has not in these respects chosen one people rather than another.

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

The highest activity a human being can attain is learning for understanding, because to understand is to be free.

I make this chief distinction between religion and superstition, that the latter is founded on ignorance, the former on knowledge.

Philosophers conceive of the passions which harass us as vices into which men fall by their own fault, and, therefore, generally deride, bewail, or blame them, or execrate them, if they wish to seem unusually pious.

As though God had turned away from the wise, and written his decrees, not in the mind of man but in the entrails of beasts, or left them to be proclaimed by the inspiration and instinct of fools, madmen, and birds. Such is the unreason to which terror can drive mankind!