6. There are spirits whose sole study is to acquire to themselves knowledges, because they are delighted only with knowledges. Therefore these spirits are permitted to wander about, and even to pass out of this solar system into others, and to procure for themselves knowledges. They have declared that there are earths inhabited by men, not only in this solar system, but also out of it in the starry heaven, to an immense number. These spirits are from the planet Mercury.