“Yet the Aristotelianism of Rome, with its idea of potentiality, offers, we are bound to think, a point of contact with the underlying philosophy of Dialecticism. Rome occupies an intermediary position.”
What has Basel to do with Rome? In the above quotation Van Til is making a startling point. On the one hand earlier on in the paragraph he acknowledges that Rome has way too much orthodoxy in it for there to be an easy alignment with “the theology of Crisis.” Nevertheless, Rome’s theology and the theology of Basel are not devoid of all commonalities.
So, when he speaks of “the Aristotelianism of Rome” he has in mind, of course, the theology of Thomas Aquinas. Van Til, rightly or wrongly, always associates Roman Catholicism with Thomism. But what is most important here for our purposes is to identify what he means by Rome’s “idea of potentiality.”
We need to be brief here (a fuller scholarly treatment of this subject is beyond our purview). But the idea of “potentiality” entails what some call a chain, or scale, of being. Potency is understood opposite of actuality. And every thing has potency, which means it has potential toward actualization. Only God is pure actuality, having no potency in himself. Everything else is on its way toward actualization. This idea is often connected with the idea of the analogia entis – or analogy of being. Things on the scale of being—God who is the greatest being, man as an actualizing agent—relate to one another analogically. While there is much dissimilarity between God and man—God is fully actualized, we are not—there is also a commonality as well: God and man are both beings. So, it is an analogy based on the fact of what God and man have in common: being. And while God and man differ quantitatively in their being they are not qualitatively different.
So, what has this to do with Barth (here Van Til uses the broader term “Dialecticism,” but he has primarily Barth in mind)? After all, does Van Til not know that Barth absolutely rejected the analogia entis (goes so far as associating it with the anti-Christ)? Does Van Til not know that Barth speaks about the “qualitative difference between eternity and time?” Where in the world could Van Til find common cause between Aquinas and Barth?
While it is true that Barth begins with the “qualitative difference between time and eternity” he does not stay there. Especially as his theology develops from the time of his Romans commentary, he recognizes that he cannot stop with the qualitative difference if God and man are ever to be reconciled. Somehow God and man, time and eternity, the Creator and creature must be brought together. At the same time his actualistic doctrine of God does not allow him to have a God who is eternal or timeless in the absolute sense. So he speaks about “God’s time.” For Barth God’s time is his time of grace in the eternal decree who is Jesus Christ. Jesus Christ is himself both the electing God and the elect man. With that, then, Jesus Christ is both the eternal God and the temporal man. And he is such in his eternal nature. There is for Barth no logos asarkos, that is a Christ who is ever understood as being without flesh and therefore without time. Jesus Christ is himself “God’s time for us.” That means that God and man, eternity and time, are co-terminus realities. The relationship between God and man is relative and not absolute. For God is forever and from all eternity this God who has time for us in Jesus Christ.
To be sure, this is not the same thing exactly as Thomas’ analogy of being. It is more like an analogy of God’s time. And while the construction differs, what remains as a common ground between Thomas and Barth are their commitment to placing God and man in a relative relationship rather than an absolute one.
Both Thomas and Barth then stand over against the Reformed understanding of how God and man relate. For the Reformed God and man relate covenantally. They both have a relationship in absolute distinction from the beginning. The way in which they relate, then, is not through some kind of ontological bond. Rather, the bond is covenantal. It is a relation established by God and guaranteed and sealed by divine fiat—not through bringing God and man in under a common ontological reality (being for Thomas, time for Barth).
But there is one last commonality between Thomas and Barth, and it is based on the commitment to their respective views of analogy. And that is they both stand in antithesis to the Reformed Faith. Reformed theology will not allow this common sharing or an ontological bond between God and man. For the problem between God and man is not ontology. The problem is a matter of hamartiology. And the solution is soteriological and covenantal. And therein lies the difference between the Reformed Faith on the one hand and Thomas and Barth on the other.
 Van Til, C. (1947). The new modernism: an appraisal of the theology of Barth and Brunner. The Presbyterian and Reformed Publishing Company: Philadelphia. P. 8.