The question of causality in both theology and philosophy (not to mention the sciences) is definitely a thorny one. Much ink (and blood) has been spilled in controversy over this very point. Is God sovereign over all things? If so, how? Does God’s sovereignty mean that creaturely freedom is an illusion? If creaturely freedom is not an illusion, is God’s sovereignty thereby limited? What about prayer? If God is sovereign, then what good will prayer do? How can we possibly expect to have an effect on God’s ways and works if he has already planned everything out from before creation? Or if prayer is effectual, does that mean then that God really isn’t totally sovereign?
These are the kinds of difficult questions that arise in relation to question of causality. On the surface, it may seem somewhat of an abstract and abstruse discussion. Yet when we begin to think about it, we come to realize that the way we understand causality, both divine and human, has a massive impact on our lives, from prayer to evangelism to finances to suffering.
I have personally found Karl Barth helpful in working through these questions. As most readers of Barth know, however, he can sometimes be difficult to follow through all the twists and turns and heights and depths of his thought, especially when it comes to issues like causality and concursus (that is, the relation between divine and human action). Christopher Green helps to illuminate our journey with Barth just a little bit when he writes:
While Barth avoids the traditional use of the causal terminology, he still adopts it for his own nuanced reasons. In the Spirit, God works something that is rightly called “causality” in divine providence because he and his covenantal partner (i.e., the creature) mysteriously “condition” each other. God’s Spirit makes this “conditioning” possible on each side, and the irreducible mystery of providential causality is grounded within God’s own life. For this reason, the question of the “causality” of the Spirit in the created world is an incontrovertible enigma:
The divine pattern must be normative on both sides. In His procession from the Father and the Son, the Spirit is a particular Spirit, the Holy Spirit. He is always a Spirit of love and peace and order, but now He is the Spirit of the love and peace and order which according to the eternal mystery of the unity of Father and Son will always be a mystery in the ways and works of the Spirit in the created order, and therefore in Christian existence. The Spirit can never be observed or imprisoned by the creature, and therefore by the Christian, but in all His majesty He will always be a free Spirit and—therefore the Holy Spirit.
This element of pneumatic mystery in concursus opens a door for Barth to talk about causality without thinking of it as a “mechanical” causality. The Spirit is the effect of Jesus Christ’s action in providence, and this is a conditioning of his partner, the creature. Due to the fact that Christ’s action takes place in the Spirit, his action on the creature transpires in such a way that it is causal and yet, ineffably nonmechanical. Christ’s providential action is “causal” because it is a “conditioning” of the creature, but this is not a “mechanical” conditioning.
Barth’s appropriation of “causal” language refers to a kind of covenantal “conditioning” that is meaningful in two ways: First, and in the light of the importance that is placed on the atonement in §49.1, it may be more accurate to say that God’s work in providence is “causal” in the sense that it is a soteriological “conditioning.” Barth’s way of soteriologically adopting the term causa should not be a surprise on account of his “radical correction.” Since Barth’s doctrine of election is elevated above his doctrine of providence, the traditional terminology is not only placed in a soteriological context, it is retained so that it can be meaningfully redefined. Second, and regardless of the way that Barth’s soteriology qualifies his account of the appropriate use of causal terminology, divine and human agents do have a real impact on each other due to this soteriological context. God may even be said to be “determined” by the creature in the act of prayer. This happens, furthermore, because God allows this exchange to occur mysteriously in the Spirit. The Holy Spirit is the “Lord of our hearing” in such a way that “no method” can approach him on the side of the creature.
For Barth, this solution will only satisfy the theologian if the “cause” question originates within the context of a prayerful commending of the Word. That is, the question of God’s ongoing relation with the creature in concursus can only be properly raised when this is done from the standpoint of Barth’s soteriology. The creature will only pray in the context of providence when this also occurs in the context of reconciliation. Creation cannot be isolated and investigated here. All too often, however, the “cause” question is motivated by a need to safeguard the doctrine of divine omnipotence with a conceptual apparatus and, therefore, the theologian attempts to gain knowledge of creation apart from reconciliation, that is, apart from prayer. Attempting to gain knowledge of creation in se and apart from reconciliation is characterized by Barth in §49.2 as motivated by fear. However, a practical knowledge of the divine concursus that arises out of prayer is satisfied with the irreducible mystery of the Spirit’s action, which embraces both creation and reconciliation as mutually supportive contexts. I will elaborate on this version of causality more fully in the following three chapters. However, at this point it suffices to say that the prayer that the Spirit encourages is one that jettisons dissatisfaction and suspicion from theology, and therefore, the motive that traditionally encourages the use of causa.
Barth makes it clear in §49.2, and especially in his discussion of succurrit, that Christ is certainly omnipotent over all things. However, for Barth, Jesus Christ is the King who enacts the omnipotent rule of God because the Spirit that enacts this causality in the created world is “His Holy Spirit.” The Holy Spirit is a predicate of Christ’s action in providence that not only safeguards the inexplicability of the mysterious relation between reconciliation and providence, but conceals the historical effect of his power in practice.143 The Spirit is “a subjectivisation of the objective Word of God.” In other words, only in the context of faithful prayer can the creature come to apprehend what it means that she is the “partner” of God. Just as Christ possesses the Spirit, he possesses the creature’s prayer and directs it to apprehend this mystery analogically, without grasping it fully. This also offers a clue for understanding what Barth means when he speaks of human freedom in §49.2.
As a predicate of Christ’s work, the Spirit is God’s action that guarantees the origin, execution, and effect of every event in history. Therefore, this leaves us with one final implication: that the act of the creature is truly free because the Spirit is the mystery of God’s empowering love in Jesus Christ: “Where the Word and Spirit are at work unconditionally and irresistibly, the effect of their operation is not bondage but freedom.” At once, in the Holy Spirit, divine providence is incomprehensible, but is also faithful to the Creator’s purpose for the creature—that she should be free. The ongoing freedom of the creature in divine concursus is guaranteed in Christ’s action on account of the mystery of the Spirit’s mediation.
Now this may leave us with just as many questions (if not more!) than before. There is certainly mystery here, and I doubt that we will ever fully comprehend the ways and works of God, especially with what pertains to our own role as human beings in relation to them. What we can learn, however, is that we must not reduce God’s sovereign and providential activity, especially the mysterious “blowing of the Spirit wherever he wills”, in mechanistic or logico-causal terms. God is not a machine (neither are we for that matter!), nor does he operate like one. The ineffability of the Spirit means that all of our explanations will ultimately fall short of the reality to which they point.
In the end, Barth and Green help us to see that however we may understand this mystery, it is only in prayer that we can actually begin to grasp it – not necessarily in systematic or explicable categories, but in the kind of knowledge that we can only acquire by participation in the reality of which we speak. This is indeed why Barth often stressed that apart from prayer, all theological work is done in vain.
 Green, C.C., 2011. Doxological Theology: Karl Barth on Divine Providence, Evil, and the Angels J. Webster, I. A. McFarland, & I. Davidson, eds., London; New York: T&T Clark. pp.87-90. For citations of Barth, see Green.