31. One can compare the spirits who have come to people the Earth to troops of emigrants of diverse origin who came to establish themselves on a virgin soil. They find there wood and stone with which to make habitations, and each one gives to his own a special seal, according to the degree of his knowledge and ingenuity. They group themselves by reason of analogy, of origin, and taste. These groups end in time by forming tribes, then nations, each having its own customs and characters.