In the last chapter I was trying to indicate what Aquinas says about the Trinity considered in itself. In the jargon of modern theology, I was concerned with his teaching on the 'immanent Trinity'. But Aquinas also believes that the 'immanent Trinity' is the 'economic Trinity'. 1 For he thinks that God both acts in the world and is present in it. 2 That is why he holds that the Trinity matters to us. He does not see the doctrine of the Trinity as a complicated exercise in speculative celestial physics. He thinks of it as a wonderful truth which is full of implications for people. For he believes that the Trinity is 'economic' in and for humanity, and that its significance lies in the fact that we may come to share in its life.
Before we can appreciate why Aquinas thinks this, however, we will need to look further at his understanding of people. We have already seen something of what that amounts to, but the picture that has so far emerged still needs to be added to. Aquinas maintains that we share in the life of the Trinity as human beings, and to grasp the implications of that notion we must first know what he thinks human beings are.
Aquinas obviously thinks of people as created, and as part of a world held in existence by God. Because he thinks of them as having