"Is Jenson correct to suggest that Barth's binitarianism results from an inherent Western trinitarian deficiency? Do the filioque and the vinculum amoris necessarily lead to a mere modus? David Hart, from an Orthodox perspective, and Joseph Ratzinger, from a Catholic perspective, have commonly shown the depth of the personal reality of the Spirit according to the Western/Augustinian theology of the Spirit as the ineffabilis quidam complexus of Father and Son. Defending the Augustinian view, they have identified 'communio' itself as the crucial, personal mode of the Spirit, just as sonship and paternity are respectively the personal modes of the second and first persons. . . . From this, one can perhaps go further, arguing that the fully personal nature of the Spirit is most perfectly secured by the filioque--as, for example, Stratford Caldecott has argued in the context of a defense of Meister Eckhart's trinitarianism. Caldecott suggests that the Holy Spirit is only distinguished from the Father and Son by virtue of his 'dual origin': 'the filioque tradition permits us to distinguish the Persons purely as relations within the Trinity. The Orthodox allege that this undermines our sense of the Father as the sole principle of the Trinity. The Latins might reply that by rejecting the filioque the East reduces the distinctive 'spiration' of the Spirit to no more than another 'coming forth' from the Father. Some theologians have suggested that the dispute could be solved by agreeing to speak of the Spirit proceeding from the Father 'through' the Son. But this also has a disadvantage: it presents the Son as a mere way-station or tunnel. The metaphor of 'giving,' as distinct from 'generating' or 'proceeding,' helps us remember that God is no impersonal substance but only and forever personal. But then, if the Son is truly to be the image of his Father, he must also be a giver in his own right, and not just a transmitter of the Father's gift to himself. . . . The Father remains the sole principle, because the Son has nothing he has not received from this source. But the Trinity is asymmetrical reciprocity, not a symmetrical hierarchy proceeding from the Father. Its asymmetry is precisely the root of its dynamism as eternal Act, eternal perichoresis'".
Aaron Riches, "Church, Eucharist and predestination in Barth and De Lubac: convergence and divergence in communio," Communio: international Catholic review 35, no. 4 (Winter 2008): 574n34.