Ecumenism is the word that describes the historical movement for global church unity. I used to think of it as either a boring academic exercise in doctrinal compromise, or a winner-takes-all struggle to forge one monolithic superchurch.
After five years in the field (I work for a Lutheran ecumenical organization), I'm no longer dismissive. The quest for church unity is a wild, wondrous, and strange act of penitence for Christians' often callous disregard of that little word one in John 17 and the Nicene Creed. We confess that the Holy Spirit has called one church into being. But almost all the evidence points in the opposite direction. What does this mean? And how should we respond to it?
Coping with Division
Throughout church history, Christians have come up with many ingenious ways of explaining why the one church can be divided into many factions. The easiest, of course, is to say that everyone outside of a particular circle is not actually part of the church. That was how the church father Cyprian dealt with it: By definition the church is one, indivisible; so if there appear to be "divisions," the reality is simply the true church versus a wicked pretender. And outside the church, there is no salvation.
But this approach works only if the isolation is strictly maintained. What happens if Christians in one "church" encounter those of another "church" and are startled to find genuine faith, piety, and good works?
At this point the more generous but almost as problematic notion of the "invisible church" comes in. It's usually based on Jesus' parable about the wheat and the tares. The basic idea is that godliness describes only individuals, not ...