Finding the movement of the other kind of body which, being primary (awwal), must exist. In what manner must it exist? Is its mover a mover by nature or by will? 1

Undoubtedly, with regard to the other body, one may say that it must surround (gird dīgar) other bodies. This condition can be one of two kinds. We imagine that the elements of that body can either be indicated because of the nature of the body’s position or that such a reference cannot be made. ² If the latter were true, then the set of elements would not accompany the body in its place, or such a reference could not be made to such elements (juzw-hā). If reference to the elements of a body cannot be made with regard to the entire body, then the elements must have diverse natures. Consequently, such a body cannot be simple, being composed of elements having different natures. But if such a reference can be made, then the body in such a position will be receptive to motion. And we have asserted that whatever is receptive to motion must have a propensity (girājistan) for motion in its nature. Thus, there is such a propensity in the nature of such a body. It cannot have a propensity for straight (rectangular motion), for such a propensity would imply the existence of a direction prior to the body. ³ Hence, the propensity of the primary body must be circular in its own place. It should be noted that from a simple body of one nature circular movement cannot proceed from its nature nor from its will, for natural movement is seeking one’s nature and going from a condition that is true at the present time to another condition. If we assume that its nature is in its proper place, where it should be, then its nature will not require it to change its place at that moment at which it no longer seeks to separate itself from its actual state. If it moved, its movement would not then be in accord with its nature. The mobility of a body is the condition whereby it seeks to separate itself from its present state, a state which disagrees with its nature. ⁴ Moreover, since that condition which would remove it from the body is not in accord with its nature, and since the body will not aim for such motion or move towards it, the body will therefore not be induced to perform such a motion. Nevertheless, any condition which is taken away from a body by circular motion will return to it. Its removal represents a restoration to the body. Consequently, circular motion which is not external is due to free will – not to its nature alone. That kind of body having such a motion is therefore moved by will ( khwāst).