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Who’s With Me!?, Pt. 3: Following Jesus as a Centered Set

January 2, 2023

by Greg Henson, CEO Kairos University; President of Sioux Falls Seminary and David Williams, Kairos Executive Partner; President of Taylor Seminary


A few weeks ago, we noted that “we are called to follow Jesus into the world, by the power of the Spirit, to the Glory of God the Father. And we are invited to do so in community.” That begs the question, who is in that community or, at least, what does it mean to be in that community. Paul Hiebert began this conversation over 40 years ago by providing a few frames for how we might answer these questions. Last week, we looked at his description of bounded sets. Today, we are discussing centered sets. Some, including Hiebert himself, have raised up centered sets as a potentially better means by which to think about or envision a Christian community. Like with bounded sets, Hiebert eventually referred to them using different terminology (e.g., well-formed extrinsic sets). For our purposes, we will refer to them as centered sets.

Centered sets, like bounded sets, have well-formed boundaries. The key difference, however, is that they are not created by drawing such boundaries. That is to say membership in a centered set is determined by one’s relationship to a particular reference point (i.e., the center). Whereas membership in a bounded set could be determined by the intrinsic attributes of each person, one’s inclusion in a centered set requires boundaries but, more importantly, a reference point. Alan Hirsch and Michael Frost illustrated the concept of a centered set by referring to how livestock might be raised in Australia. They noted that a bounded set approach would be to put a fence around the cattle (which they suggest might be common in the United States). In Australia, they noted, a ranch might put a water well in the center of the field. The cows in the set, therefore, are those who return to the well.

One of the best and most succinct summaries of Hiebert’s “centered set” theory is in a paper titled, “Understanding Christian Identity in Terms of Bounded and Centered Set Theory in the Writings of Paul G. Hiebert.” It was co-authored by Michael Yoder, Michael Lee, Jonathan Ro, and Robert Priest. In that essay, they offer the following summary:

Centered Sets

  • The category is created by defining a center or reference point and the relationship of things to that center
  • Members are things that move toward, or are in relationship to, a common center or reference point (although they may vary in distance from the center)
  • While centered sets are not created by drawing boundaries, they do have well-formed boundaries that separate things inside the set from those outside it
  • Centered sets have two types of change inherent in their structure: entry or exit from the set (based on relationship to the center), and movement toward or away from the center

It is important to note the existence of boundaries within the concept of centered sets. Many have written books and articles describing centered sets as something with fuzzy or unclear boundaries. That is not true (Hiebert eventually referred to those as fuzzy sets, and we will discuss those next week). Rather, a centered set has boundaries but inclusion is based on direction, orientation, or relationship with the center. For example, a remote villager in India (the example used by Hiebert) could choose to follow Jesus, which means he is oriented toward the center and therefore included in the set. His inclusion is connected to his entry into the set (i.e., choosing to follow Jesus) and his orientation toward Jesus. He is included in the set even though he doesn’t yet display all of the other markers of being a Christian (e.g., participation in a local community of faith, cognitive understanding and coherent articulation of orthodox beliefs, etc.). Centered sets are still binary (i.e., either – or) in their construction because a person is either in the set or out of it. The boundaries still exist.

Hiebert and several other missiologists have a tendency to prefer the centered set approach to identifying the Body of Christ. Several voices within the missional theology movement share this propensity for centered set thinking. Generally speaking, their assertion is that it allows the Body of Christ and even local communities of faith to spend less time policing the boundaries and more time inviting people to move in the direction of Jesus.

Hiebert helpfully noted that this approach can be difficult in “American” cultures given their affinity for binary definitions for many types of categories. Due to the exportation of western theological education, we would suggest that the western academic tradition also tends to prefer the clarity that comes from binary definitions. In practice, this means that centered set approaches can be difficult to embrace for many churches or traditions around the world, even if they are not “American” or “Western.”

As a result, the centered set approach has been both hailed and scorned. Some believe it is the best (perhaps only) way to envision the Body of Christ while others will say it does not give enough weight to the required characteristics of being a Christian. As Hiebert continued his writing on the topic, he began to notice that some approaches to categorization didn’t have clear boundaries (i.e., they were not well-formed like bounded and centered sets). That led him to describe fuzzy sets, which is our topic for next week.

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