To Florus 5.59

The difference between possibility and necessity is as great as that between fullness and emptiness. A capacity is shown empty of the thing it can receive; if it were not empty, it could not receive it. Who would receive what he already had? Necessity, however, indicates not emptiness but fullness. It cannot receive as though empty what it already compels to exist as though full. Necessary things differ from possible things, therefore, as packed things from empty things. The capacity is protected from predetermination toward either quality, for which it is equally capable, precisely by receiving opposites. It possesses in nature the necessary good that reflects its maker’s honor: innocence naturally mixed with no evil, receptive of its own acts, both the distinct merit of good and the blame of evil.

A sinner can wound what comes to him from his own activity; he cannot discolor what he received from God’s work. The valuation of natural goodness therefore remains even in evil people. It will never be evil to have been capable of doing good and evil. But it will not benefit the person who, without actually condemning the institutions of his necessary nature, has compelled them to be of no benefit to himself. In a human being whose freedom is already developed, therefore, when he sins we assign evil to will, but nature to God its creator. If, however, an infant who has no exercise of will and displays nothing except nature’s institutions is said to be full of crime, possessing by necessity the evil another receives by possibility, the one accused as crime’s author is undoubtedly nature’s author.