"We learn that our friend's land has been overrun by invaders or stricken by famine, or that our friend has died; or, much worse, we learn that our friend has forsaken the faith or has committed some moral offense that threatens death to his soul; and we learn all this impotently at the opposite end of the world. Anyone who has lived in one country and had friends or family in another knows what Augustine means: the very availability of communications crucifies us more perceptibly on the ineradicable fact of absense, which heightens the hiddenness that casts a shadow over the best of our social relations.
"Hiddenness is the root of the matter. No one, perhaps, before Kierkegaard was so vexed by the difficulties we experience in displaying our hearts to one another. It is this, rather than the pride of original sin, the dazzle of glory, the iron rod of power, or the lure of sensuality, which casts a shadow over all social relations. We may be deceived in one another. To follow Augustine to the fourth stage, the Universe, is to see how this inexorable law applies also in our relations with the spirits and demons which imprint their character upon the institutions of the earthly city. Empire, because it unifies us, tempts us to think that this constraint can be overcome; but. . . . It d[oes] not overcome the resistance of the human heart to mutual knowledge. . . . [Lucretia] sought death because 'she was unable to disclose the purity of her conscience to the world' ([City of God] 1.19).
"These chapters are a microcosm of Augustine's social thought. Either we find that they illumine the constraints of social existence as little else in Western literature can, or we shake our heads in bewilderment and ask, 'But why was he so gloomy?' If it does not trouble us that we are ignorant of what our children are thinking, that our spouse may be sleeping with our best friend, that many inmates of our prisons may be innocent of the crimes for which they are being punished, that foreign relations are built upon a capacity to repel sudden and unforseen attack; or if we think that there are alternative patterns of political life available which are not vulnerable to treachery, stupidity, or simple conflicts of view, then we will find Augustine's somber rhetoric merely perplexing. But in that case, Augustine will say to us, we are hardly fit to be citizens of the heavenly city, in which each will be transparent to all: patebunt cogitationes nostrae invicem nobis (22.29.6)."
Oliver O'Donovan, "The political thought of City of God," in Oliver O'Donovan and Joan Lockwood O'Donovan, Bonds of imperfection: Christian politics, past and present (Grand Rapids, MI: William B. Eerdmans Publishing Company, 2004), 71-72 (48-72), small caps mine. patebunt cogitationes nostrae invicem nobis: our thoughts will lie mutually open to us (one another).