separate from matter and are not bodies, there remained no way for beings of this nature to move bodies except by commanding them to move. Hence, in their view, the celestial bodies must be living, rational beings that understand themselves and the principles that move them by commanding them.

Since it had been established in On the Soul that there is no difference between knowledge and the effect, except that the object known exists in matter whereas knowledge does not, it follows that, if beings exist that are not in matter, their substance must be knowledge, intellect, or whatever one wishes to call it.

They also held it established that these principles are separate from matter because they impart to the celestial bodies perpetual motion in which neither weariness nor fatigue overtakes them; that whatever imparts perpetual motion of this kind is neither a body nor a power within a body; and that a celestial body derives its continued existence solely from beings separate from matter. They further held it established that the existence of these principles separate from matter