For the power which is prolific of energy is perfect. For it makes other things to be perfect through its own energies. That, however, which is perfective of other things is in a greater degree perfect, as being more self-perfect. But the power which is indigent of another that pre-exists in energy, according to which indigence it is something in capacity, is imperfect. For it is indigent of the perfection which is in another, in order that by participating of it, it may become perfect. Hence, such a power as this is of itself imperfect. So that the power of that which is in energy is perfect, being prolific of energy. But the power of that which is in capacity is imperfect, and obtains perfection from the power which is in energy. PROPOSITION LXXIX. Every thing which is generated, is generated from a two-fold power.[241] * * * * * For it is requisite that the thing generated should possess aptitude and an imperfect power. And that which makes being in energy[242] that which the thing generated is in capacity, antecedently comprehends a perfect power. For all energy proceeds from inherent power. For if that which makes did not possess power, how could it energize, and produce something else? And if that which is generated did not possess power according to aptitude, how could it be generated? For that which makes or acts, makes or acts in that which is able to suffer, but not in any casual thing, and which is not naturally adapted to suffer from the agent. PROPOSITION LXXX. Every body is naturally adapted of itself to suffer; but every thing incorporeal to act. And the former indeed is essentially inefficacious, but the latter is impassive. That which is incorporeal, however, suffers through its communion with body; just as bodies are able to act through the participation of incorporeals. * * * * * For body, so far as body, is alone divisible, and through this becomes passive, being entirely partible, and this to infinity. But that which is incorporeal, being simple, is impassive. For neither is that which is impartible, capable of being divided, nor can that be changed in quality which is not compounded. Either, therefore, nothing will be effective, or this must be affirmed of an incorporeal nature, since body, so far as body, does not act, because it is alone liable to be divided, and to suffer. For every thing which acts has an effective power; so that body, so far as it is body, will not act, but so far as it contains in itself a power of acting. Hence, when it acts, it acts through the participation of power. Moreover, incorporeal natures when they are inherent in bodies, participate of passions, being divided together with bodies, and enjoying their partible nature, though according to their own essence they are impartible. PROPOSITION LXXXI.