For this Reading of the Week, I’ll let you be the judge, but it seems to me about 40 years before the emerging church began to redefine Christians according to a centered set model rather than as a bounded set, C.S. Lewis was already developing the same practical understanding! Just before the C.S. Lewis reading, let me clarify with this short description from Wikipedia:
[The emerging church movement] appropriates set theory as a means of understanding a basic change in the way the Christian church thinks about itself as a group. Set theory is a concept in mathematics that allows an understanding of what numbers belong to a group, or set. A bounded set would describe a group with clear "in" and "out" definitions of membership. The Christian church has largely organized itself as a bounded set, those who share the same beliefs and values are in the set and those who disagree are outside.
The centered set does not limit membership to pre-conceived boundaries. Instead a centered set is conditioned on a centered point. Membership is contingent on those who are moving toward that point. Elements moving toward a particular point are part of the set, but elements moving away from that point are not. As a centered-set Christian membership would be dependent on moving toward the central point of Jesus. A Christian is then defined by their focus and movement toward Christ rather than a limited set of shared beliefs and values.
Again, you be the judge: How does this emerging church understanding compare to our C.S. Lewis Reading of the Week, taken from Mere Christianity? (So enough from Ken Symes, let’s get on to C.S. Lewis!)
[The] situation in the actual world is much more complicated than that. The world does not consist of 100% Christians and 100% non-Christians. There are people (a great many of them) who are slowly ceasing to be Christians but who still call themselves by that name:
some of them are clergymen. There are other people who are slowly becoming Christians though they do not yet call themselves so. There are people who do not accept the full Christian doctrine about Christ but who are so strongly attracted by Him that they are His in a much deeper sense than they themselves understand…. And always, of course, there are a great many people who are just confused in mind and have a lot of inconsistent beliefs all jumbled up together. Consequently, it is not much use trying to make judgments about Christians and non-Christians in the mass. It is some use comparing cats and dogs, or even men and women, in the mass, because there one knows definitely which is which. Also, an animal does not turn (either slowly or suddenly) from a dog into a cat. But when we are comparing Christians in general with non-Christians in general, we are usually not thinking about real people whom we know at all, but only about two vague ideas which we have got from novels and newspapers. If you want to compare the bad Christian and the good Atheist, you must think about two real specimens whom you have actually met. Unless we come down to brass tacks in that way, we shall only be wasting time.
C.S. Lewis, Mere Christianity (1952; Harper Collins: 2001) 208-209.