I love the class and this topic has given us good conversation fodder for the past few weeks. Here is the beginning of my paper. Influential in the second paragraph is Mark Driscoll; I believe I first read him talking about this topic in Radical Reformission: Reaching Out Without Selling Out. I don't remember if these are the exact terms he uses or not.
The Importance of Defining an Irreducible Ecclesiological Minimum
The advantages of having a clear, minimalist definition of the church are multi-faceted. Simply phrased, the church planter can know what to start and what not to start. Without a clear goal, leaders lack direction. They will expel energy building something that may not be a healthy church. Perhaps most discouraging of all, church planters without a clear goal of what they are starting are not equipped to measure their progress or even know when or if their mission is complete. A driven, faithful planter could invest his blood, sweat, and tears into a community, only to wake up two years later and not know how to measure the fruit of his labor.
There are two extremes the planter should be aware of in knowing what not to start: 1) starting non-churches, and 2) expelling great energy attempting to create a church with the cultural artifacts of a different church in another culture. These two errors may be described as syncretism and Fundamentalism. The syncretistic church blends in so much with the culture that it neuters the Gospel and fails to even be a church. The Fundamentalist church fails to distinguish between the church and the culture as well – instead presuming that replicating aspects of the culture falls within the goal of starting new churches. Here the Gospel is added to, and the result is a crippled Gospel and irrelevance in the host culture. Thus neither the syncretistic nor the Fundamentalist approach to church planting generates a God-glorifying church that is reaching people in culture.
With the prize available to the planter in having a clear definition of a church and the pitfalls of failing to have a clear definition, one may move on to the task of defining an irreducible ecclesiological minimum (IEM).