A man without passion is only a latent force, only a possibility, like a stone waiting for the blow from the iron to give forth sparks.

Our duty is to be useful, not according to our desires but according to our powers.

Sadness takes up the pen more readily than joy.

Emancipation from error is the condition of real knowledge.

Man is saved by love and duty, and by the hope that springs from duty, or rather from the moral facts of consciousness, as a flower springs from the soil.

Action is coarsened thought; thought becomes concrete, obscure, and unconscious.

Common sense is the measure of the possible; it is composed of experience and prevision; it is calculation applied to life.