Thus, on the one hand, the falsest judgments, whether based on isolated facts or only on appearances, always embrace some truths whose sphere, whether large or small, affords room for a certain number of inferences, beyond which we fall into absurdity. The ideas of St. Augustine, for example, contained the following truths: that bodies fall towards the earth, that they fall in a straight line, that either the sun or the earth moves, that either the sky or the earth turns, &c. These general facts always have been true; our science has added nothing to them. But, on the other hand, it being necessary to account for every thing, we are obliged to seek for principles more and more comprehensive: that is why we have had to abandon successively, first the opinion that the world was flat, then the theory which regards it as the stationary centre of the universe, &c. If we pass now from physical nature to the moral world, we still find ourselves subject to the same deceptions of appearance, to the same influences of spontaneity and habit. But the distinguishing feature of this second division of our knowledge is, on the one hand, the good or the evil which we derive from our opinions; and, on the other, the obstinacy with which we defend the prejudice which is tormenting and killing us. Whatever theory we embrace in regard to the shape of the earth and the cause of its weight, the physics of the globe does not suffer; and, as for us, our social economy can derive therefrom neither profit nor damage. But it is in us and through us that the laws of our moral nature work; now, these laws cannot be executed without our deliberate aid, and, consequently, unless we know them. If, then, our science of moral laws is false, it is evident that, while desiring our own good, we are accomplishing our own evil; if it is only incomplete, it may suffice for a time for our social progress, but in the long run it will lead us into a wrong road, and will finally precipitate us into an abyss of calamities.