The parts of the whole, everything, I mean, which is naturally comprehended in the universe, must of necessity perish; but let this be understood in this sense, that they must undergo change. But if this is naturally both an evil and a necessity for the parts, the whole would not continue to exist in a good condition, the parts being subject to change and constituted so as to perish in various ways. For whether did nature herself design to do evil to the things which are parts of herself, and to make them subject to evil and of necessity fall into evil, or have such results happened without her knowing it? Both these suppositions, indeed, are incredible. But if a man should even drop the term Nature [as an efficient power], and should speak of these things as natural, even then it would be ridiculous to affirm at the same time that the parts of the whole are in their nature subject to change, and at the same time to be surprised or vexed as if something were happening contrary to nature, particularly as the dissolution of things is into those things of which each thing is composed.