In her contribution to ‘Theological Theology: Essays in Honour of John Webster‘, ‘The Sinlessness of Christ’, Katherine Sonderegger looks at a variety of ways of thinking about the doctrine non posse peccare. In its own right it’s a fantastic essay, focusing primarily on Aquinas, with a glance at liberation theology as well as patristic theology. She also sketches out her own approach which closely follows the classical accounts (namely, that Christ did not and could not sin), which she develops in light of and against Karl Barth and Edward Irving’s understanding of Christ’s assumption of fallen human flesh. It seems to me, though, that her own approach is marred by a serious misreading of Barth, and it’s on this specific aspect of her essay that I want to focus on.
Sonderegger gets a good deal of Barth right. However, the misstep occurs when she equates the assumption of fallen flesh, as Barth conceives it, with the possibility of sinning, even though Christ didn’t in fact sin. Sonderegger pegs this idea as disrupting the unity of the hypostatic union, which is a serious error for any christological doctrine to commit, especially for a christology so relentlessly committed to the hypostatic union as Barth’s. I’ll quote her at length:
‘Should we assume this new maxim of our day, that Christ could have sinned – indeed as a child of Adam bore sin in his flesh – but in fact did not…Christ cannot sin because the bare possibility of it – posse peccare – is the possibility, ex hypothesi – of the human nature of Christ going its own way, seeking its own end, joining in the rebellion against God. The personal unity of such a Christ can only mirror the obedience of Adam and Eve: it is good, we might say, as far as it goes. But we do not seek an amalgam of this sort in Christology! What we can break apart is fragile, whether riven apart in the end or no.’ (pp. 274-275)
The logic appears to go something like this: (1) Christ assumed fallen flesh (2) to assume fallen flesh to assume the possibility of either sinning or not sinning (3) Christ either could have sinned or not sinned (4) thus the unity of the person of Christ is threatened, even if it in fact did not occur. The correction she offers is after the manner of Cyril of Alexandria: Sonderegger argues that Christ experienced suffering perfectly, and was born into a perfect reconciliation with God, instead of, as she sees Barth, healing and redeeming and reconciling the humanity over the whole course of his life.
Sonderegger’s logic is tight enough so far as it goes, except that Barth says nearly the exact opposite when it comes to Christ’s sinlessness. There’s a lot of material on this in the Church Dogmatics, but to my mind the most immediately applicable text is from IV.2, which I’ll quote (again, at length):
‘We may indeed say that the grace of the origin of Jesus Christ means the basic exaltation of His human freedom to its truth, i.e., obedience in whose exercise it is not super-human but true human freedom.
From this point it can be understood as the grace of the sinlessness of His human essence. This, too, is a grace – a determination of the human essence of the Son of God from the fact that it has existence in Him alone, that it is actual only in the Son of Man.
“Without sin” means that in our human and sinful existence as a man He did not sin. He did not become guilty of the transgression which we in our human essence commit. He bore an alien guilt, the guilt of all men, without any guilt of His own. He made our human essence His own even in its corruption, but He did not repeat or affirm its inward contradiction. He opposed to it a superior contradiction. He overcame it in His own person when He became man. And we can and must say that He overcame it at the deepest level by not refusing to accomplish the humiliation of the Son of God to be not only a creature but a sinful creature…the sinlessness of Jesus was not a condition of His being as a man, but the human act of His life working itself out in this way from its human origin.
He did not sin, because from this origin He lived as a man in this true human freedom – the freedom for obedience – not knowing any other freedom…Because and as He was man only as Son of God, it was excluded from the choice of his acts. In virtue of this origin of His being, He was unable to choose it. Therefore He did not choose it. And He did not do it…it is not really of necessity, but only in fact, that human nature wills to sin, and does sin, and therefore can sin. We are in self-contradiction in this capacity, in our posse peccare. It is not our genuine freedom, our liberum, but only our servum arbitrium, that we choose evil…we do not act freely but only as those “possessed”, when we do wrong…thus the man Jesus does not transcend the limits of the humanity common to Him and us, or become alien to us, when in His acceptance of human essence even in its perversion He does not repeat the perversion or do wrong, when in virtue of His origin He cannot will or do it. He is just what we are and how we are. The only difference is that He is it in genuine human freedom.’ (pp. 92-93)
When Barth is taken on his own terms, the force of Sonderegger’s criticism all but evaporates. Barth’s own logic is far more subtle than Sonderegger’s on this point, since (and the enhypostatic/anhypostatic distinction is surely in play here implicitly) for Barth, it is because of the hypostatic union that Christ is unable to sin. It is not a case of two natures, one divine and one human, each with the possibility of ‘doing their own thing’. He truly is human, and to be truly and humanly free is to be unable to sin, since that it is only out of its origin in the Son of Man and not out of its own being that the human essence of Christ has any being at all. Far from rendering the unity of the person of Christ a frail construct, Barth is seen to have, on the basis of the unity, affirmed a strong doctrine of the non posse peccare.