And whereas the most peculiar characteristics of spiritual properties are two--one of them Setting in Motion (Impulsion), and the other Perception--it is incumbent upon us to show that to every moving body there is a [A]moving cause (ground, reason, motive, pretence). Then it will become evident to us therefrom that bodies moving in motions over and above the natural motions--an example of natural motions is the sinking of the heavy, and the rising of the light--have moving[B] causes, which we call souls or spiritual powers; and that we further show that any body, in so far as it shows signs (traces) that it is perceptive, such perception by it cannot be validly ascribed to its body, except because of powers (faculties) in it that are capable of perception. We now start by saying that not a shadow of doubt or perplexity hampers the mind, as to things, that some of them share some one thing in common, and differ in an other; and that that which is shared in common is other than that in which they differ. The mind encounters all bodies whatsoever as having this in common, viz. that they are bodies; and afterwards it encounters them as differing in that they move (in different ways); otherwise there would be no such thing as rest of a body, and not even such a thing as motion of a body, except along a circle, seeing that of motion in a straight line it is established by its very form that it will not proceed save from stoppings and to stoppings (resting-places to resting-places). Hence it is evident that bodies are not to be clothed with the attribute of motion because they are bodies, but for reasons (causes) above and beyond their corporeity, from which causes their motions proceed, like the resulting of the footprint from the walker (or, just as the effect proceeds from the agent).