Leo Was Wrong: Jesus’ Divine and Human Activity and the Communicatio Idiomatum
As Christians who stand at the end of a long line of doctrinal development (or, perhaps, in our own ‘moment’ somewhere in the middle!) we should be careful to recognize the punctuated moments along the way for what they are — and not take them as fully fleshed-out, mature statements of that doctrine. This means that those who are rightly championed as heroes of the faith should not always be held up as offering a definitive statement of a given doctrine, even if they made important contributions.
Pope Leo I’s famous statement on the communicatio idiomatum (communication of attributes) is an important example of this. During the christological controversy of the mid-fifth century Leo famously sent a theological treatise (the Tome) from Rome to the east, where the Council of Chalcedon was to deliberate over the doctrine of Christ’s person and the way in which his divinity and humanity are related to one another. The degree to which Leo’s Tome was influential over the final formula is a matter of some scholarly debate, but the Tome itself was commended and circulated along with the Council’s official documents. It has since become an important snapshot from the history of the development of doctrine.
Leo’s work includes one of the most significant early statements on the communicatio, a doctrine with origins in the language of the New Testament that had found some earlier expression in Tertullian and had become particularly important in the debates between Cyril and Nestorius. Cyril suggested that the unity of divinity and humanity in Jesus meant that language that is proper to only one of these (for example “glory” on the one hand, and “suffering” on the other) could be predicated of the divine-human Jesus. Not only this, but this “communion of properties” in Jesus was realiter — it spoke of a real condition in the metaphysics of the incarnation. Nestorius, by contrast, looked at such New Testament statements as “they crucified the Lord of glory” (1 Cor. 2:8) and argued that the communicatio is merely figurative language. The two natures remain distinct, and the communicatio idiomatum would be a confusion of natures if it was taken to be metaphysically real.
The statements of Leo and the Council to this end are highly important in advancing beyond the Alexandrian-Antiochene dispute of the day. Leo wrote:
Each ‘form’ [nature] does the acts which belong to it, in communion with the other — the Word, that is, performing what belongs to the Word, and the flesh carrying out what belongs to the flesh. The one of these shines out in miracles, the other succumbs to injuries.
Leo is working out what it would mean for the church to confess that, in Jesus, two natures are united in one person. How are his actions (which is, after all, the narrative data we actually have in the gospels) to be described if Jesus lives ever in and through both complete divinity and complete humanity? What about those moments in the gospel stories when Jesus seems to be super-powered — the working of miracles, knowledge of the future, and supremely in defeating death itself? What do we make of Jesus’ humanity in these moments? On the other hand, what of those moments when Jesus seems just as mortal as you and me — his growth and development, ignorance of the day of his return, and supremely in suffering and dying? What do we make of Jesus’ divinity in these moments?
Leo’s solution was to maintain an operative distinction in the activity of the incarnate Word: the divine side (the person of the Word) does those things appropriate to divinity, such as miracles, while the human side (the flesh of Jesus) does those things appropriate to humanity, such as suffering. Their distinction is held together by a personal unity, however: each performs its acts “in communion with the other” (and not in some sort of metaphysical isolation, as if Jesus could push aside his human nature and actualize a healing without it).
This would be worked out with more (much needed) precision in subsequent generations. And it is a vital step forward in this long history of development — so Leo is rightly praised here for his contribution. But the statement of the Tome is far from decisive … and, in fact, is seen in the light of later development to be somewhat misleading.
If we are to preserve the distinction of the two natures, it seems as though we ought to say something like Leo has said: the divine Word does the acts that are divine, the human flesh does the acts that are human. What is wrong with that?
As the church continued to work out just what “divine” and “human” natures are, and what aspects of life they entail (e.g. the mind, soul, will, ‘energies’ by which the will is actualized, etc.), it came to see Leo’s statement as insufficient. Who, after all, is the one person who performs these acts in the gospel narratives? It is Jesus who acts — not the Word here, but the flesh there. And so by the seventh century we get language like “theandric” and “theanthropic” (literally “divine-human”) to describe Jesus’ person and activity in terms of the unity of these seemingly disparate natures. Though the natures remain distinct there is no metaphysical isolation of them from one another; whatever Jesus does, he does in and through both natures (the communicatio operationum).
We might say that Jesus’ activity, rather than divine-and-human, is always divine-human. When he changes water to wine or raises a dead girl to life, he is doing so in and through the unity of both natures. When he anguishes in the garden and surrenders his spirit to the grave, both of his natures are at work — each in their own proper way, as later theologians would attempt to describe with some specificity.
When we speak of Jesus’ suffering on the cross, then, we ought to say that he suffered by virtue of his humanity but not that he suffered strictly in his humanity. He suffered as a divine-human person, and like all that he does this is a theandric activity.
This is not only the necessary qualification to Leo’s fifth century statement about Jesus’ divine activities and human activities, but a thoroughgoing correction that ought to isolate the Tome to its own moment in doctrinal history more than it has. Leo’s rendition of the communication of attributes and the divine-and-human activity of Jesus seems to suggest that Jesus can act in one nature (in communion with the other) rather than theandrically — even that “the Word” does the divine things and “the flesh” does the human things. Judged by the standard of later orthodoxy, this is insufficient as an account of Jesus’ personal unity.