We must have our hearts and souls in the right place to engage in ecumenism, but that’s not quite enough. We must also devote the best of our minds to this work. Ecumenism requires careful biblical exegesis, probing historical investigations, philosophical clarity about our terms and definitions, and theological precision. There is a good reason bilateral dialogues always take place in teams—lots of people, with specialties in many different areas, are needed to keep the balance and make sure all important points, including the range within each denominational family, receive due attention. In addition to this specialized work, Christians not directly involved in the dialogues are needed to study the results, reflect on them, and build on them.
To that end, ecumenists have developed certain concepts that help them accomplish their tasks. These concepts give a framework for how to go about their dialogues and understand the various churches better; they also help to identify the difficult areas and map out the way toward a new future together. Since these terms have a habit of coming up quite often in ecumenical circles, it’s good to have some basic familiarity with them. All of them serve to help Christians to discern what is and what is not church-dividing. Identifying that line between unity and separation is essential to moving the churches to a new relationship with each other that better reflects God’s will.
The first thing to figure out in a dialogue is who exactly the partner is. In ecumenical dialogue, we’re talking to other Christians. That’s pretty straightforward, though not quite as straightforward as you might think. This is because different churches make different kinds of claims about themselves, and that itself is one of the differences that must be worked out in ecumenism.
For instance, the Orthodox regard themselves as being nothing other than the church of the apostles two thousand years later, in perfect and unbroken continuity; in addition, they don’t believe any other churches qualify under this description. Roman Catholics believe that the church that they confess in the Creed “subsists” in the Catholic Church (Lumen Gentium §9). “Elements” of the true church may exist outside the Catholic fold, though never with the same completeness or perfection as inside the Catholic Church (Unitatis Redintegratio §3). Various smaller Protestant churches also claim to be the one true church; many of them think that the true church more or less vanished from the early Middle Ages until the Reformation or even afterward. Most Anglican, Lutheran, and mainline Protestant churches do not consider themselves to be the only true church, but certainly a true church, and they reject other churches’ claims for exclusivity even if they don’t make such a claim for themselves.
None of this should come as a surprise; if it weren’t the case, we’d have no need for ecumenism at all! But what it does imply for our dialogues is that every church has to respect the other church’s self-description, even if it doesn’t agree with that description. Each church is allowed to say what it thinks about itself without being immediately criticized. For some churches, this will mean associating with communities that don’t qualify as churches, in their view. For others, this will mean associating with churches that claim far too much, in their view. But it is a necessary exercise in respect that leads us forward.