that comes into being. Rather, it requires others to cooperate with it and assist it, and even then it encounters opposing and obstructing forces. One of the greatest examples of this is the “starless ninth sphere.” Many metaphysical philosophers, astrologers, and others suppose that its motion causes all events, and their knowledge of the causes of events goes no further than this motion. They either regard it as known to the Necessary Existent through the mediation of an intellect or a soul, or without such mediation; or else they deny that it is an effect and regard it as necessarily existent in itself. This claim of theirs is among the most utterly unsound, although, despite their intelligence, they fail to recognize this, and many people do not know how to refute them on this point.
Anyone who looks at the sky knows that its motion is not the cause of all celestial motions. It is often said that, through its easterly motion, all the spheres within it move from east to west. Yet each sphere also has another motion peculiar to it, contrary to this motion: the sphere of the fixed stars, and the spheres of the sun, the moon, and the other celestial bodies that recede, run their courses, and disappear from view. These differing motions do not arise from that motion—they run counter to it—nor are their spheres effects of that ninth sphere. Even if we suppose that events are brought about by the motion of the heavenly bodies and the various configurations formed through trines, squares, sextiles, conjunctions, and the like, it is well known that those