Vicarious representative action comes over time … to acquire a broader significance in Bonhoeffer’s theology. In Christ, humanity is always something shared and never solitary. Ontology and ethics are inseparable. Human beings live naturally in the ethical situation of encounter. They may, of course, seek to avoid this, by notionally reducing the ethical task to the selective application of certain fixed principles—and then “withdrawing from responsibility for the whole, to a purely private bourgeois existence, or even into the monastery”—but this simply betrays a false understanding of ethics, and a shallow appreciation of life. The isolationist approach, says Bonhoeffer, will always fail “due to the historicity [Geschichtlichkeit] of human existence.”
In Bonhoeffer’s Ethics, vicarious representative action is worldly, responsible action, freely undertaken by human beings out of love for other “real” human beings. And because all such action takes place necessarily within history, it will always entail risk, and a degree of moral ambiguity. Those who act responsibly “in their own freedom” must themselves weigh the merits of their actions and be responsible for their decisions. There are no formal, saving rules of the game to which they can appeal—for in this case “they would no longer be truly free”—just as there is no “ultimately dependable [human] knowledge of good and evil” in this God-reconciled, but still fallen, sicut deus world. The responsible actor must, therefore, surrender to God, at the very moment of execution, “[t]he deed that is done, after responsibly weighing all circumstances in light of God’s becoming human in Christ.”