Reading the Dogmatic Constitution Lumen Gentium (8), one could sympathise with Professor Hans Küng who was quoted by Dr Mobbs as saying that 'at least since Vatican II it is no longer admissible for a single confession (church) to pose as the one and only saving and true Church of Jesus Christ.'
Instead of stating that the Church of Christ is the Catholic Church - as Pope Pius XII did in his encyclical Mystici Corporis Christi (13) - Lumen Gentium says that 'the one Church of Christ 'subsists in' the Catholic Church, governed by the successors of Peter and by the Bishops in communion with him.
'Nevertheless, many elements of sanctification and of truth are found outside its visible confines. Since these are gifts belonging to the Church of Christ, they are forces impelling towards Catholic unity'.
Thus the Church of Christ seems to transcend the Catholic Church, and as the Declaration Dominus Jesus (16) states, while it exists fully in the Catholic Church, it is present and operative also in churches which lack full communion with the Catholic Church.
Cardinal Ratzinger warned that 'the Christian faithful are not permitted to imagine that the Church of Christ is nothing more than a collection of churches and ecclesial communities' and he said that the Christian faithful are required to profess that there is an historical continuity - rooted in the apostolic succession - between the Church founded by Christ and the Catholic Church (Dominus Jesus, 17).
But we are not clearly told, that by this very historical continuity, the Church of Christ is the Catholic Church.
The difficulty lies in the expression 'subsists in'. Cardinal Ratzinger explains that 'with this expression the Second Vatican Council sought to harmonise two doctrinal statements: on the one hand that the Church of Christ, despite the divisions which exist among Christians, continues to exist fully only in the Catholic Church, and on the other hand, that outside Her structure many elements can be found of Sanctification and Truth, that is in those churches and ecclesial communities which are not yet in full communion with the Catholic Church' (Dominus Jesus, 16).
Yes, I believe Christ has established one Church, and that Church is the Catholic Church, but for me, this truth has not been unambiguously stated by the Second Vatican Council.