This argument for the infinity seems to make against the personality of God. "An actuality that is in none," it will be said, is no one's actuality. If personality is some sort of limitation, how can the infinite be other than the impersonal? This ground is beset with formidable difficulties. See General Metaphysics, Stonyhurst Series, p. 282. Such reply as I can make is the following: I would rather call personality an exclusiveness than a limitation. Then I might observe that the three Persons of the Blessed Trinity, while having one and the same nature in common, are mutually exclusive of one another as Persons. But as this mystery lies beyond the ken of philosophy, I prefer to reply that the actuality of God is exclusive of absolutely everything that comes within our direct cognition: it is exclusive of the entire universe. So St Thomas, though not so the pantheistic school, who make their Absolute formally inclusive of all. Here surely is a great difference. God then, according to St Thomas, is not infinite in the sense of formally containing within His own being, as part of Himself, the being of this world. He is distinct with a real, physical distinction from the universe which He has created. He is infinite, not as being identified with the universe, but as being infinitely above it: and better than it, so far above it and so far better than it that the universe, as compared with His being, has in that comparison no being and no goodness at all. See last note in Chapter XVI. True, His actuality is "in none," but that is because it is complete and perfect in itself, individualised in itself, filling up the measure of divinity and identified with it, so that there can be no second God, and none could possibly be God but He who is God. Thus God can be called by no proper name, as Michael or John, applied to angel and to man, to distinguish one individual from his compeers. Is not this completeness and exclusiveness to be called personality? Personality, a distinguishing perfection of the highest of creatures, cannot well be denied to the most perfect of beings, their Creator.
Of God and His Creatures: 1.43