The question here arises, not only in reference to vital agents, but to _all finite, created causes_: Does the active cause of change (together with the passive potentiality of the subject of change, whether this subject be the agent itself as in immanent activity, or something other than the agent as in transitive activity),—does this active power account _adequately_ for the new actuality educed in the change? It obviously does not; for the actuality acquired in the change is, as such, a new entity, a new perfection, in some degree positively surpassing the total reality of the combined active powers and passive potentialities which it replaces. In other words, if the actuality resulting from the change is not to be found in the immediate active and passive antecedents of the change, then we are inevitably referred, for an adequate explanation of this actuality, to some actual being above and beyond these antecedents. And to what sort of actual being are we referred? To a being in which the actuality of the effect resides only in the same way as it resides in the immediate active and passive antecedents of the change, that is _potentially_? No; for this would be useless, merely pushing the difficulty one step farther back. We are obliged rather to infer the existence of an Actual Being in whom the actuality of the said effect resides _actually_: not formally, of course, as it exists in itself when it is produced through the change; but eminently, _eminenter_, in such a way that its actualization outside Himself and under His influence does not involve in Him any loss of perfection, any increase of perfection, or any manner of change whatsoever. We are compelled in this way to infer, from the existence of change in the universe of our direct experience, the existence of a transcendent Immovable Prime Mover, a _Primum Movens Immobile_. All the active causes or principles of change which fall under our notice in the universe of direct experience are themselves subject to change. None of them causes change in any other thing without itself undergoing change. The active power of finite causes is itself finite. By educing the potentiality of other things into actuality they gradually use up their own energy; they diminish and lose their active power of producing effects: this belongs to the very nature of finite causes as such. Moreover, they are themselves passive as well as active; interaction is universal among the finite causes which constitute the universe of our direct experience: they all alike have passive potentiality and undergo change. Now, if any one finite cause in this system cannot adequately account for the new actuality evolved from the potential in any single process of change, neither can the whole system adequately account for it. What is true of them