"As with all human language applied to God, the use of the term communion [(κοινονία)] theologically has carried with it the dangers of shaping our conceptions of God in a way that comes to mirror our social assumptions and hopes: God ends up looking like a multiethnic society, a congress, a church council, a congregation, and on and on. What we require for our understanding of 'communion,' which is a human and social construct, is that its meaning be informed by God's reality, not the other way around. If God is never called a 'communion' in Scripture, God is clearly called 'one.' And hence, God's 'oneness' is what needs to inform the Church's 'communion': 'that they may be one even as we are one' (John 17:22 RSV; cf. vv. 21, 13). The 'oneness' that is God's, however, is, in this prayer, identified as something peculiar: 'as we are one,' in Jesus' words. How is God one? Do we know what this means? Here some eristological nuance will be helpful. . . ."
Ephraim Radner, A brutal unity: the spiritual politics of the Christian church (Waco, TX: Baylor University Press, 2012), 8. "Eristology . . . is the study of hostility in its disordering forms and forces" (4-5). This critique of social trinitarianism begins on p. 7, with an appreciative reference to Paul Fletcher, Disciplining the divine: toward an (im)political theology (Farnham, UK: Ashgate, 2009).