 Besides perfection and necessity, immateriality, eternity, and immutability also seem to point to simplicity as their ground. Because God is simple, he cannot have parts and so cannot have material or temporal parts. And because God is simple, he cannot harbor any unrealized potentialities, and so must be immutable. The centrality of DDS to medieval philosophical theology is shown by its position in the order of topics in Aquinas’ Summa Theologica. It occurs as Question 3 right after Question 2 on the existence of God.