The last chapter sketched the ideal of the Church and her essential mission. The realization of that ideal in the existing Church, visibly embodied here in earth is extremely fragmentary and imperfect. The Church that is one, and holy, and apostolic, and catholic, the brotherhood in Christ of all mankind, knit into unity by the fellowship of the Holy Spirit, remains a vision of the future, though a vision which, once seen, mankind will never relinquish until it be accomplished. "I believe in the Holy Catholic Church," it has been said, "but I regret that she does not as yet exist." What does exist is a bewildering multiplicity of competing "denominations," whose points of difference are to the plain man obscure, but whose mutual separation is in his eyes an obvious scandal and an offence both against charity and against common sense. Why cannot they agree to sink their differences, and to unite upon the broad basis of a common loyalty to Christ? To what purpose is this overlapping and conflict? The reluctant tribute of the ancient sceptic--"See how these Christians love one another"--has become the modern worldling's cynical and familiar jibe; and when to the spectacle of Christian disunion is added the observation that professing Christians of all denominations appear to differ from other men, for the most part, "solely in their opinions" and not in their lives, the impulse to cry "A plague upon all your Churches" may seem all but irresistible. Yet the problem is not susceptible of any cheap or hasty solution. Unity is the Church's goal; but the Church cannot arrive at unity by mere elimination of differences. Agreement to differ is not unity: an agreement to pretend that the differences were not there would not even be honest. What is needed is a sympathetic study of the divergent traditions and principles which lie behind existing differences, with a view to discovering which are really differences of principle, and which rest merely upon prejudice. Unity, when it comes, can only be based upon mutual understanding and synthesis. The task will not be easy, and the time is not yet.