6. I do not suppose there was a change in the substances; that is to me an obvious absurdity; what I say is that there was a change of the qualities, and I maintain that in respect of them God is a Creator. For just as we may say that a house is built of stones, but cannot say that, because the stones have become a house, they do not remain stones in substance: for I maintain that the house is built in virtue of the quality of arrangement, the former quality of the stones having been of course changed; so, it seems to me, God, while the substance remained the same, created a change of its qualities, and I maintain that this change justifies us in saying that God made the world.