The formula of Chalcedon didn’t sit well with everyone. There were Eastern Christian for whom the official language of two natures (physis) in Christ was not acceptable. These Christians, known as Monophysites, sided with Cyril of Alexandria, and thought that the alternative two-nature Christology tended toward the heresy of Nestorius. They did not want to go there. Now it wasn’t that they had any issues with the full deity and full humanity of Jesus; they simply differed about how to talk about it. What compounded the problem was a bit of a language barrier, since some of these Eastern churches did not commonly use Greek. But their Christology was condemned by the majority in the West, and that was the end of that… or was it?
The streams of the Christian tradition that were deemed heretical – the Coptic, Syrian, and Armenian Orthodox Churches, primarily – did not fade away. They persist to this day, and they have an interesting but different take on those ancient theological conversations. In brief, they generally reject the term monophysite, used to describe their Christology. Rather, they insist, they use the term miaphysite, which refers not to one simple nature but one united or composite nature – both fully human and fully divine. They actually say that the charge leveled against them centuries ago is unfair, based on presumption and misunderstanding.
What is more, in recent years they have gained new prominence – facing anti-Christian persecution from Muslim fundamentalists in the East, and participating in the larger Christian community in the West, where they are interacting with other Christian groups (I even taught a couple of Coptic Orthodox priests at Tyndale Seminary in Toronto, the largest evangelical seminary in Canada, which I understand is an approved teaching site for Coptic Orthodox priests). My point is that longstanding theological formulations and terms, while not unimportant, do not afford us the opportunity to think of these ancient controversies as completely settled matters about which we no longer have to think. The best of our theological work may have considerable staying power, and we many not want to reopen old debates, but we ought not err too far in the other direction and bury consideration of those issues, never to see the light of day again.
Whatever one thinks of the Eastern Church traditions mentioned here, it should be a well-considered opinion (and not simply based on this one question, either). We need to continually bring theological work back to Scripture, and also evaluate it in light of the fruit it bears in the world as people live it out.