“If we affirm the Creator-creature distinction, we have to say that the issue of one and many must distinguish two levels. We have one and many in the Creator and one and many in creatures. In the Creator, one and many are equally ultimate. God always exists both in his unity as one God and in his plurality, consisting in the three persons of the Trinity. We must avoid saying that the oneness in God is more ultimate, so that the three persons of the Trinity somehow come about after one God exists, or that God is really one and that he merely appears to us as three when he interacts with us (the error of modalism). We must also avoid saying that the diversity in God is more ultimate, so that the three persons exist first and then somehow join together into a three-member society that agrees to act jointly (the error of tritheism). So we can see that God is both one and many, and neither can be reduced to the other.
Now what about the issue of one and many among creatures? God in speaking through his Word creates the universe with its own created unity and diversity. Both unity and diversity owe their reality to God’s speech, which expresses his character. God himself is one and many. He then expresses his inner unity and diversity in his speech. God the Father functions as speaker, God the Son as the Word, and God the Spirit as the breath of God’s speech.
Let us become more specific by considering what happens with horses. We have already observed that there are many horses, but they belong together because they are all horses. They belong to the same species. They share common characteristics. How does this one and many come about?
God has planned to create a universe with horses. The universe includes many horses in their diversity, and each particular horse in all its particularity comes into being according to God’s plan. Likewise, God planned a universe in which the distinct horses are united in belonging to one species, the species of horse. They have common characteristics because God planned their commonality. Their commonality or unity is no more ultimate than their diversity, because God’s plan includes both unity and diversity. His speech articulating his plan includes unity and diversity.
Thus, Christian thinking in terms of the Creator-creature distinction leads to a distinct approach to the issue of universals. The Christian position is not merely a realist position, because “horseness” is not prior to the particularities of individual horses. God’s plan is of course prior to the actualization of his plan in the creation of particular horses. It is also prior to the actualization of his plan in the creation of the species of horse within the world. God’s plan includes unity and diversity for the race of horses and for the particular horses. The execution of his plan in time and space manifests unity and diversity. We now have around us both a species, namely, the species of horse, and the particular horses. God’s plan includes both the generality, that is, the unity, and the particularities that show the diversity among living things.
Using the Creator-creature distinction, we naturally have to distinguish God’s knowledge of horses from our knowledge. God knows comprehensively and originally, while we know partially and derivatively. We do know about the existence and characteristics of particular horses, like Sally the palomino mare. We also recognize that, by God’s design, all horses belong together and share some characteristics. But we do not know everything that God knows about the particular mare Sally, nor do we know everything about horses in general. We can point to some characteristics that make us think that it is appropriate to classify Sally under the general term horse. But we could perhaps be fooled by some clever ruse, and we do not know everything that goes into God’s making Sally a horse.
It is worthwhile dwelling on the nature of God’s unity and diversity for a bit longer, because it is important as a foundation for creation and for logic.
The class God applies to all three persons of the Trinity. It is the general category. The persons are distinct; each one is fully God; each is an instantiation of God. Thus, within the Trinity we find a unity in the class and a diversity in the instantiations.
We can see a divine manifestation of generality and particularity at another level. When God the Son becomes incarnate, he is the unique manifestation of God on earth. Jesus says to Philip, “Whoever has seen me has seen the Father” (John 14:9). Jesus is the unique instantiation of God on earth in his incarnation. Thus the idea of instantiation, though applicable to all three persons, is especially seen in the person of Christ. What about the idea of class, the generality? The category God covers all three persons. God the Father is more often the most prominent representative in the Godhead, as when Jesus says that he is ascending to “my God and your God” (John 20:17). Thus we have reason to associate class or classification with the Father. Finally, the Holy Spirit represents the presence of God in believers, and unites us to Christ. He acts as the bond of association or relationship. So we can link the Holy Spirit to relationships—including even the relationship between the generality or classification (“God”) and the instantiation (Christ in his incarnation).
God is absolute and original. Hence classification, instantiation, and association have their origin in him. They also apply derivatively to created things. Each dog is an instantiation of the species of dogs, where the species is the classification. Each dog in its individuality has an association with the species to which it belongs, with the other instances of dogs, and with other kinds of creatures as well.”
(Poythress, Logic, 145-148)