I overheard the remark from a visiting Protestant, made after the Mass, about how difficult it is to attain unity among such diverse opinions in Christendom. That was the gist of it, at least, and I had to smile and sigh with some regret at the same time (where I was tucked away washing mugs). She is correct, it is difficult indeed if all we see are those diverse opinions, with no ground upon which to argue that Jesus was The Truth, not the ghostly image of diverse opinions on what is true. As a favourite author succinctly taught me in his writings many years ago, the principal question really boils down to this question: "Who do you say that I am?", as it contrast starkly against the question that preceded it: "Who do people say that I am?" The latter is about opinions. The former is not, and is not meant to be. Jesus Christ is so central to everything, and the Christian mission so important, that it stretches the imagination to suppose that he sent us off on a mission to proclaim our good opinions to the world.
A second look tells me that the above comes off as harsher than it should be. Let me point out that I do not know all, most or even enough of the crucial truths, but we have the Spirit of Truth among us (all Christians), so there is cause for hope, but also cause to work towards unity.