Intro
Seems to me there are two sorts of "unity" often confused and thought of as one. We want Christians to be united with each other and for the divisions among Christians to end. This is, I take it, what the Pope in some recent remarks meant by "full visible union...". But he also asked the rhetorical question: "Is Christ divided?" Christ is one and His Church is one because it is His body. But the oneness or unity of the Church is not the same as the oneness or unity of Christians whose divisions, let us suppose, have ended.
This difference is, then, very important to understanding the following paradox: Christ's Church cannot be divided but members within it and some of those professing to be members are, amongst each other, divided.
So how do we solve this paradox?