Public judgment is constrained by this limit, and in its struggle to wrest the initiative from private judgment, it loses the ground of its authority if it succumbs to immodest pretensions. It is not only that there is more truth to be known than it can know; there is also more judgment to be given than it can give. Its work lies on the surface of things, and only anticipates the deep judgment of God by not pretending to forestall it. To the extent that it exceeds its limits it loses credibility as a community undertaking, and appears in the world as a prophetic, didactic, or ideological force, armed with an authority springing from beyond community discourse.
What, then, are the limits of practicability that constrain a judgment performed in public on the community’s behalf? They are three: (i) that not everything known can be publicly expressed or certified; (ii) that judgment has only certain modes of expression open to it; (iii) that it lacks final authority.
From The Ways of Judgment (Bampton Lectures) by Oliver O’Donovan, pages 27-28.