Once churches have begun to recognize each other by converging on certain topics, it is time for them to discuss in more detail what they have in common and what separates them. Consensus, the “second stage” of ecumenism, means coming to a new understanding about previous disagreements. Consensus is most often the result of bilateral dialogues between two churches only.
As a church moves through history, it weighs and tests opinions. Some are judged good and faithful. Other are judged false and dangerous. In a situation of division, one church often doesn’t know what kind of judgments another church has made. Perhaps my church has come to reject something that your church rejected long ago. Perhaps your church has come to accept something that you used to think was intolerable. Discovering these developments can open up the possibility of a new consensus between previously divided churches.
The goal is to create a state of what is called more technically called “differentiated consensus” or “unity in reconciled diversity.” The aim is not to iron out everyone’s confessional theology into one single mega-theology for the whole church, suppressing the differences of emphasis or concern. Such an attempt would impoverish the church, not to mention meeting with virulent resistance. The task instead is to establish the boundaries within which all Christians can coexist.
For example, all Christians are characterized by belief in the Holy Trinity: Father, Son, and Holy Spirit. Certain misinterpretations of this doctrine are inadmissible, like the ancient heresies of subordinationism, tritheism, or modalism. But within the right trinitarian doctrine established by the church councils, there are different emphases unique to various churches. They are not rejected, but they are not mandatory for all the other churches, either. In a differentiated consensus, the churches lay out the common ground they share and require of one another, but they also have the opportunity to specify the particular emphases that are important to their own tradition. The other church recognizes these items as legitimate and acceptable. Such differences do not destroy what Christians share in common and therefore are not church-dividing.