That God is ‘self-existent’ is a doctrine often either taken for granted or wholly neglected in contemporary theology. Here Brian D. Asbill explores this theme and its larger dogmatic implications in the theology of Karl Barth, showing how God's aseity permeates Barth's understanding not only of the Trinity but also creation, revelation, and even redemption. On the other hand, because Barth believed that God's being is in activity (not only in se but ad extra), by virtue of God's love and freedom, divine aseity functions only with respect to God's ‘pronobeity’ – that in his very character God is for us. By virtue of election, the self-existence of God must be comprehended not as isolation and solitude but as that which grounds God's being for creatures in Jesus Christ.

Unfolding over nine chapters, Asbill's rigorous and thorough study begins with a sketch of the aseity doctrine in history and in theological context before turning to Barth's sometimes traditional, sometimes creative use. Part I examines the place of aseity in the earlier Göttingen Dogmatics, then finds signs of both continuity and genuine revision in the Church Dogmatics (focusing particularly on the knowledge and reality of God in volume II/1). Part II deftly navigates the love and freedom of God with respect to God's ‘personality’ (God's objectivity in his self-revealing) and aseity (God's subjectivity in God's life in himself). These two are ‘equally balanced’, paradoxically simultaneous and also sequential, so that neither one ultimately must be subordinated to the other (p. 97). Part III breaks down the ‘anatomy’ of the doctrine of aseity before rendering an expert summary of God's character as one who is self-sufficient and unconditioned, and who (not remaining content to be so) shares the abundance of God's life with creatures – even becoming conditioned by them (cf. CD II/1, pp. 313–15), freely putting himself ‘under an obligation’ to men and women (II/2, p. 101).

Key to Asbill's exposition is Barth's conviction that this relationship – between God's aseity and pronobeity, God's primary and secondary objectivity – is asymmetrical, moving necessarily only from God to the human creature. It is for this reason that Barth avoids a sort of Hegelian panentheism: God's self-involvement with creation is wholly free and gratuitous, and does not trespass upon God's inner life as Father, Son and Spirit. Conversely, just as the knowledge of God is impossible without divine action, so too human existence depends upon God's gracious extension of God's own life. ‘God simply is this trinitarian event of knowing and loving’ (p. 177), so that the life God has in himself is one directed towards an other.

Asbill shows himself a capable reader of Barth, demonstrating how God's life ad intra need not be affirmed at the expense of God's life ad extra – a temptation that contemporary Barth studies has not entirely escaped. Since aseity and freedom are tightly wound in Barth's thought, God's aseity simply cannot be understood apart from God's pronobeity; the two are dialectically ordered, so that ‘the teleology of God is God's pronobeity in aseity’ (p. 177). This work is a fine contribution to the field, as well as to the growing trinitarian resurgence and the recognition of Barth's place in it. Theologians working today who are about the ‘retrieval’ of medieval and post-Reformation scholastic thought would do well to maintain an open posture towards Barth's dialectical realism especially at points such as this – where he appropriates dogmatic abstractions critically, showing a willingness to subject them to revision in order that they not float free from the gospel event. The aseity of God need never be neglected, then, so long as the concept is made to serve the church's witness and not vice versa.