CHAPTER XXI—That Things aim at Likeness to God in being Causes of other Things

A THING must be first perfect in itself before it can cause another thing. The last perfection to supervene upon a thing is its becoming the cause of other things. While then a creature tends by many ways to the likeness of God, the last way left open to it is to seek the divine likeness by being the cause of other things, according to what the Apostle says, We are God’s coadjutors (1 Cor. iii, 9).⁵⁴⁵⁵⁴⁵In chapter XXII it is argued that the movement of the heavenly spheres goes to engender things on earth (motio ipsius coeli ordinatur ad generationem). In chapter XXIII it is argued that the movements of the heavenly spheres are not done mechanically, but are set up and kept going by intelligence, the star-bearing spheres being either all moved by God, or all by angels at His bidding, or all by the primum mobile, the primum mobile itself being either moved by God, or by an angel, or having a soul of its own, but in any case obeying God. “It makes no difference,” says St Thomas, “to our present purpose, whether the heavenly sphere is moved by a subsistent intelligence united with it as a soul, or by an intelligence subsisting apart; and whether each of the heavenly spheres is moved by God, or whether none of them is moved by Him immediately, but they are moved mediately through created spirits; or whether the first alone is moved immediately by God, and the others through the medium of created spirits; provided it be held that the movement of the heavens is the work of spirit.”