We have already anticipated the objection arising from the consideration that the state resulting from a change is sometimes in its totality less perfect than the state which existed prior to the change. Even in such cases there results from the change a new actuality which was not in the prior state, and which cannot be conceived as a mere part or residue of the latter, or regarded as equivalently contained in the latter. Even granting, as we must, that the net result of such a change is a loss of actuality or perfection in the subject of change, still there is always a gain which is not accounted for by the loss; there is always a new actual state which, as such, was not in the original state. A more obvious objection to the principle arises from the consideration of vital action; but it is based on a misunderstanding of the principle under discussion. Living things, it is objected, move themselves: their _vital_ action is spontaneous and immanent: originating within themselves, it has its term too within themselves, resulting in their gradual development, growth, increase of actuality and perfection. Therefore it would appear that they move and perfect themselves; and hence the so-called “principle of change” is not true universally. In reply to all this we admit that vital action is immanent, remaining within the agent to perfect the latter; also that it is spontaneous, inasmuch as when the agent is actually exercising vital functions it need not be actually undergoing the causal influence of any other created agent, or actually dependent on any such agent. But it must, nevertheless, in such action, be dependent on, and influenced by, _some actual being other than itself_. And the reason is obvious: If by such action it increases its own actual perfection, and becomes actually other than it was before such action, then it cannot have given itself the actuality of this perfection, which it possessed before only potentially. No doubt, it is not merely passively potential in regard to such actual perfections, as is the case in non-vital change which results in the subject from the transitive action of some outside cause upon the latter. The living thing has the active power of causing or producing in itself these actual perfections: there is interaction between its vital parts: through one organ or faculty it acts upon another, thus educing an actuality, a new perfection, in this other, and thus developing and perfecting its own being. But even considered as active it cannot be the adequate cause of the actuality acquired through the change. If this actuality is something _really_ over and above the reality of its active and passive potential principles, then it remains true that change implies the influence of an actual being other than the subject changed: _Quid quid movetur, ab alio movetur_.