As to the substantial form (which is the principle of activity), although it is said to have a kind of ubication on account of the matter to which it is terminated, nevertheless, of itself, it has no capability of formal ubication, as we have already shown. Hence the extent to which the active power of an element can be applied is not to be measured by the ubication of its matter; and although no cause can act where it is not virtually by its power, yet a cause can act where it is not present by its matter. The direct answer to the argument proposed would, therefore, be as follows: “A body cannot act where it is not present either by itself or by its power.” _Granted._ “But _actio in distans_ is an action which would be exerted where the body is not present by itself, as is evident.” _Granted._ “And where the body is not present by its power.” _False._ To the reason adduced, that “there is no medium of communication,” we simply reply that such a medium is not required, as the active power constitutes an indefinite sphere, and is already present after its own manner (that is, virtually) wherever it is to be exerted; and therefore it has no need of being transmitted through a medium. This is the radical solution of the difficulty proposed. But the notion of an indefinite sphere of activity, on which this solution is grounded, is, in the eyes of our opponents, only a whimsical invention, inconsistent, as they think, with the received principles of philosophy. We must therefore vindicate our preceding answer against their other objections. _A second objection._—A sphere of power, they say, is a mere absurdity. For how can the active power be there, where its matter is not? The matter is the first subject of its form; and therefore the form must be in the matter, and not outside of it. But in a primitive substance the active power is entitatively the same thing with the substantial form; accordingly, the active power of a primitive substance must be entirely in its matter, and not outside of it. And the same conclusion is to be applied to the powers of all material compounds; for in all cases the form must be supported by the matter. How is it, then, possible to admit a sphere of power outside of its matter, and so distant from its matter as is the sun from the planets?