Divine Filiation and the Trinity in Thomas Aquinas: Reassessing Rahner’s Critique

The scholastic tradition is often criticized for starting from abstract principles or philosophical definitions. In this way, scholastic theology is frequently contrasted with post-conciliar theology, which is developed on the basis of the Paschal event, understood as the hermeneutical criterion for the whole of theology. Karl Rahner accuses Thomas Aquinas of “isolating” the Trinity from other areas of theology, such as soteriology, anthropology, moral theology, and spirituality. He also criticizes Aquinas for separating Christology from the Trinity, arguing that in the Thomistic account of the Incarnation it is not essential that the Son becomes incarnate, since any divine Person could, in principle, have done so. Rahner contends that this doctrine weakens the connection between God’s inner Trinitarian life and the missions. Consequently, our adoption as children of God would no longer be grounded in the Son’s own sonship, and what God reveals of himself in history would not truly express who he is as the Triune God. The purpose of this article is to show that such criticisms do not accurately represent Thomistic teaching and to present the doctrine of our divine filiation within a Trinitarian Christological framework. It will first examine the relationship between the immanent Trinity and the economic Trinity, then present the Thomistic doctrine of the divine missions and processions. Finally, it will address the role of the Holy Spirit and our adoptive divine filiation, all considered from a Thomistic perspective. Alongside the Summa theologiae, particular attention will be paid to Aquinas’s biblical commentaries, where he focuses on the Trinitarian economy and its implications for salvation, drawn directly from his reading of Scripture.