There is only one virtue, justice; only one duty, to be happy; only one corollary, not to overvalue life and not to fear death.

All children are essentially criminal.

The arbitrary rule of a just and enlightened prince is always bad. His virtues are the most dangerous and the surest form of seduction: they lull a people imperceptibly into the habit of loving, respecting, and serving his successor, whoever that successor may be, no matter how wicked or stupid.

Anyone who takes it upon himself, on his private authority, to break a bad law, thereby authorizes everyone else to break the good ones.

I feel, I think, I judge; therefore, a part of organized matter like me is capable of feeling, thinking, and judging.

They mistake the first manifestations of a developing sexual nature for the voice of God calling them to Himself; and it is precisely when nature is inciting them that they embrace a fashion of life contrary to nature's wish.

It seems to me that if one had kept silence up to now regarding religion, people would still be submerged in the most grotesque and dangerous superstition ... regarding government, we would still be groaning under the bonds of feudal government ... regarding morals, we would still be having to learn what is virtue and what is vice. To forbid all these discussions, the only ones worthy of occupying a good mind, is to perpetuate the reign of ignorance and barbarism.