This comes in the context of a facebook discussion, where the issues of Barth being a modalist, his trinitarian theology and doctrine of election were brought up.
So the issue here basically gets into to very fundamental aspects of Barth’s theology, election and trinity. Barth locates his discussion of the trinity at the beginning of the Dogmatics, and he very quickly rejects the term ‘person’, because he doesn’t think its possible to define it in a way that doesn’t lead to tritheism. He opts for ‘modes of being’, instead, which is generally recognized as not being a very helpful definition since the first thing anyone thinks of is modalism. He uses this language because he sees it as a way to protect the one-ness of God while at the same time recognizing the other ‘modes of being’ – the Son and the Spirit.
Barth’s overall trinitarian theology follows his theology of revelation closely – there is the revealed, the revealer, and the revelation, which would map onto God, the Spirit, and Jesus. He thinks backwards from the given of God’s self-revealing – for this revealing to have taken place, what must be true of God? From there he arrives at the basic structure of his trintarian thought. Barth is also very big on perichoresis – the inter-relations of the Father, Son, and Spirit – as being constitutive of the being of the Trinity. This can be the source of confusion – since he rejects all the language of ‘persons’, it can look incoherent, as a lot of people seem to have thought.
Now, with regard to election. This is Barth’s most original contribution to modern theology (though there are anticipations of it in the early church) because he completely dissolves the classical problem of the ‘absolute decree’ and completely reverses the typical order of election. Instead of God electing some humans and sending Jesus to save them, God eternally elects Jesus. In Christ, we have the eternal will and grace of God. Jesus is election, predestination – and in him all humanity are elect. So, in a sense, the question of:
‘Does that not posit election of humanity as a necessary part for God to be Triune? ‘
…has a real grain of truth to it, but we have to quickly add this: God does elect humanity from all eternity in Christ. Christ is election, grace, and the will of God. There is no ‘God behind the back of Jesus’, no hidden decree, no secret will – there is Jesus. This election of grace, however, is *free* – a free movement of grace, which has its origin within God himself and is not conditioned, constrained, or obligated by anything outside Godself. It is not necessary but free in the deepest possible sense. There is room in Barth for more Hegelian interpretation – determining, becoming, event, etc – but I don’t personally buy into it, because it does lead to all sorts of things like creation being a necessary aspect of God’s becoming, which is quite problematic.