What Christ does is precisely to give effect to reality. He affirms reality. And indeed He is Himself the real man and consequently the foundation of all human reality. And so formation in conformity with Christ has this double implication. The form of Christ remains one and the same, not as a general idea but in its own unique character as the Incarnate, crucified and risen God. And precisely for the sake of Christ’s form the form of the real man is preserved, and in this way the real man receives the form of Christ.
This leads us away from any kind of abstract ethic and towards an ethic which is entirely concrete. What can and must be is said is not what is good once and for all, but the way in which Christ takes form among us here and now. The attempt to define what is good once and for all has, in the nature of the case, always ended in failure.
Either the proposition was asserted in such general and formal terms that it retained no significance as regards the contents, or else one tried to include in it and elaborate the whole immense range of conceivable contents, and thus to say in advance what would be good in every single conceivable case; this led to a casuistic system so unmanageable that it could satisfy the demand neither of general validity nor of concreteness.
The concretely Christian ethic is beyond formalism and casuistry. Formalism and casuistry set out from the conflict between the good and the real, but the Christian ethic can take for its point of departure the reconciliation, already accomplished, of the world with God and the man Jesus Christ and the acceptance of the real man by God.
Dietrich Bonhoeffer, Ethics
Reflection – OK, a bit of heavy going here theologically, and if you read this a certain way, it sounds like Bonhoeffer is advocating a sort of moral relativism. I don’t think he is, and in fact I think he is quite in line with traditional Catholic moral teaching here. So let's have a little refresher course on all that.
It has always been understood in our tradition that, we can identify specific actions as intrinsically immoral, as failing in their very structure as actions to conform to the truth of humanity which is (as B. says here) only fully revealed in the person of Jesus Christ. But we cannot identify a specific action in itself to be an intrinsically good action. Certain courses of action may suggest themselves to be generally good, but there is no species of action that is always and at all times and universally ‘the good thing to do.’
For example, almsgiving is a good thing. But almsgiving done for a bad motivation (vainglory, or in service of some other evil end) or done in wrong circumstances (when it will beggar my family and cause real suffering to them, say) is not a good action. Preaching the Gospel of Christ may seem like a supremely good action, but again bad intentions (self-aggrandizement) or bad circumstances (preaching in the wrong place, to the wrong people, with the wrong words, and the wrong manner) makes it not good.
Good consequences may yet flow from these wrong acts—the alms are given, the Gospel is preached, after all—but we know that it is not the consequences that make an act good or evil, but the combination of goodness of object (the act itself), intention, and circumstances.
Formalism here refers to trying to set out the good in some theoretical fashion. ‘Do the greatest good for the greatest number,’ for example. As B. points out, this is vague to the point of being utterly useless in terms of actual practical decision making. Casuistry is, as he describes, the effort to game out every possible scenario in advance to lay out what the proper course of action would be. I would give casuistry a bit more value than he does. It is limited, but the benefit of properly done casuistry is not to provide answers in advance for every possible moral dilemma, but to demonstrate the process of moral reasoning in difficult and questionable circumstances.
But Bonhoeffer’s point is well taken. Granted that there are courses of action that are intrinsically against the moral law and cannot be considered, the consideration of what concrete course of action one should, in fact, take, is never at the level of some theory of ethics. It is the contemplation of the face of Christ, the crucified and risen one, who reveals God to man, and reveals man to man as well. We cannot know what is the good action apart from this contemplation.
Ultimately, (and this is going beyond B.’s intentions here) we cannot know in full what is the good and righteous action outside of the work of the Holy Spirit and the gifts operative in us through baptism. The moral law teaches us to avoid sin, but the concrete pursuit of virtue comes not from the law but from the Spirit at work in our hearts, conforming us to Christ, and establishing and confirming us in a living communion with Him, without which ‘[we] can do nothing’ (John 15:5).