In The New Modernism Van Til identifies the Theology of Crisis with “dialectical theology.” But what is dialectical theology? Van Til explains that dialectical theology is “at bottom activistic and positivistic.” But what in the world does that mean? He explains: “God’s being and God’s work are said to be one and the same” (p. 3). In other words, Barth’s theology is actualistic. “Actualism” is a distinctly modern approach to metaphysics, or the study of the nature of reality. It is the question of being qua being. Metaphysics seeks to discover what the essence of something or someone is.
Standing over against dialectical theology—which Van Til equates with “modern theology” as a whole—is the Reformed Faith which is “non-activistic theology” (ibid). Continuing his thesis, dialectical theology (or, Crisis Theology) and Reformed Theology are opposed to one another. But how are they opposed?
In order to answer that question we have to explain why it is that Van Til associates dialectical theology with modern theology. Modern thought, going back at least to Kant, rejects the older metaphysical tradition. That tradition is characterized by the influence of Greek metaphysical thought, especially as it influenced Western theology through Thomas Aquinas. This mode of metaphysics adheres to the idea that everything has its own particular static nature (i.e., a nature that does not change). In this mode of thinking God was understood, according to modern thinkers, as a static and abstract nature, essence, or substance. An example of this would be in the traditional doctrine of God’s immutability. Modern thinking said that this makes God out to be aloof, cold, unfeeling and abstract. He cannot change or adjust to situations. In short, he has nothing to do with us here and now. Modern thought with its rejection of medieval metaphysics proposed instead for us to think about being or ontology in dynamic terms. In this way we understand God not in terms of an abstract substance, but rather as a concrete, dynamic and living act. This is the actualism (or, more commonly used is the term “activism”) of which Van Til speaks. God’s identity, his being, is understood only in terms of his acts relative to us his creatures.
Now, Van Til sees this approach to metaphysics, or ontology, as opposed to the older traditional approach. He says only in the Reformed Faith is God “wholly self-contained.” What does that mean? It means, in short, that God is in no way identified or understood as existing in a way that is dependent upon the creature or his acts relative to it. This is in keeping with the older theology proper which understood God as being a se. God in himself does not progress or become. He is himself perfect in his being, pure act with no potentiality. That means his interaction with the creature is completely unnecessary to who he is.
But standing over against this traditional view is Barth’s commitment to the terms for ontology set by modernity. Liberalism did not like the cold, aloof God of traditional theology. So they made God to draw near to man in an immanent relationship to the creature. Liberalism was committed to actualistic ontology, identifying God with his acts toward creature. Barth opposed liberalism and emphasized God’s transcendence. But—and this is Van Til’s great observation—while emphasizing God’s transcendence Barth at the same time refused to surrender the modern and liberal commitment to actualistic ontology. However, rather than God being identified with the creature in an immanent act, for Barth God is identified with his transcendent act of electing grace. For Barth God is necessarily gracious because in a transcendent act of his own freedom he chooses to always and everywhere be the God who forgives in Jesus Christ. Therefore, as I try to show in my book, God’s eternity is not a purely eternal attribute. But his eternity is simultaneously his time for us in Jesus Christ. In other words, God from all of eternity is not “self-contained” but has his being identified with his act of grace for us in Christ. And so here—no less than in liberalism—God is dependent on the creature for his being. Creation and redemption (not to mention revelation) for Barth are not contingent acts of God, but necessary acts which give identity to the question of who he is.
Actuality dictates ontology.
And for the older orthodox Reformed view that is a completely contrary starting point for understanding God. For the older view, God’s being (ontology) dictates the activity of God in time. God’s acts are consistent with and flow from who he is in and of himself. Only this way can we say in any true and meaningful way that God acts in perfect freedom. As the answer to the children’s catechism goes:
Can God do all things? Yes, God can do all his holy will.
In these simple—yet profound—words we discover the reason why Van Til is so clear: Dialectical Theology and Reformed Theology are—and must be—sworn enemies. There is no common ground between them.
 When Van Til speaks about “the Reformed Faith” that is representative shorthand for Reformed orthodoxy. Particularly as it comes to expression in great Reformed church creeds and confessions of the 16th and 17th centuries. It is certainly a legitimate criticism here that Van Til uses a term that is both too imprecise and narrow. To be sure, there is enough variety in the history of Reformed theology and Reformed confessions to say that “the Reformed faith” is not as monolithic as Van Til seems here to assume. While we may grant that point it is important to note that Van Til’s work is not so much concerned with historical theology and the nuances found in the Reformed tradition, rather his work is “frankly polemical” (p. 3). But the granted point need not detract us because despite all the variety that there is in the Reformed confessional tradition, one thing most certainly is not: actualistic ontology.
 See God’s Time For Us: Barth’s Reconciliation of Eternity and Time in Jesus Christ (Bellingham, WA: Lexham, 2016).