What Does It Mean That the Church of Christ 'Subsists In' the Catholic Church?

Two Small Words

Few phrases from the Second Vatican Council have been argued over more than two small Latin words: subsistit in.

In its Dogmatic Constitution on the Church, Lumen Gentium, the Council wrote that the one Church of Christ, which we profess in the Creed as one, holy, catholic and apostolic, “subsists in the Catholic Church, which is governed by the successor of Peter and by the bishops in communion with him” (Lumen Gentium 8).

An earlier draft had said that the Church of Christ simply is the Catholic Church. The Council changed “is” to “subsists in.” Why? And did it mean that the Church of Christ might be found somewhere else as well?

(For the four marks themselves, see What Are the Four Marks of the Church?)

What the Church Had Said Before

Before the Council, the Church’s teaching was expressed most clearly by Pope Pius XII. In his encyclical Mystici Corporis (1943), he taught that the Mystical Body of Christ and the Roman Catholic Church are one and the same thing. He repeated this in Humani Generis (1950).

This identification was not new. It expressed the Church’s conviction that Christ founded one Church, visible and structured, and that this Church continues in the Catholic Church in communion with the Pope.

So when the Council changed “is” to “subsists in,” some concluded that it had softened or even abandoned that teaching. Others insisted it had done nothing of the kind.

Why the Wording Changed

The Council itself explained the change in the text that follows. Lumen Gentium 8 continues:

…although many elements of sanctification and of truth are found outside of its visible structure. These elements, as gifts belonging to the Church of Christ, are forces impelling toward catholic unity.

This was the point. The Council wanted to say two things together:

The one Church of Christ is found, fully and concretely, in the Catholic Church.
Real elements of that Church (Baptism, the Scriptures, faith in Christ, the life of grace, and in some cases valid sacraments and bishops) also exist outside the Catholic Church’s visible boundaries.

A flat “is” seemed to imply that outside the Catholic Church there was simply nothing of the Church at all. That would contradict the obvious reality of other Christians’ faith and holiness, which the Church had always in some way recognised (she has always accepted the validity of Baptism administered by other Christians, for example). “Subsists in” allowed the Council to keep the identification while acknowledging those elements.

What “Subsists” Means

In ordinary English, “subsists” sounds weak, as in “subsisting on a low income.” In theological Latin it is a strong word. To subsist is to exist as a complete, concrete reality in its own right.

In 2007 the Congregation for the Doctrine of the Faith issued official responses to questions about this phrase. It explained that “subsistence” means the perduring, historical continuity and permanence of all the elements instituted by Christ in the Catholic Church, in which the Church of Christ is concretely found on this earth.

The Congregation was clear on two further points:

The change from “is” to “subsists in” did not change the Church’s earlier teaching.
The Church of Christ subsists only in the Catholic Church. Other Christian communities contain real elements of the Church, but not its full reality.

Put simply: the Church of Christ is not a vague invisible federation of which the Catholic Church is one branch among many. It exists, whole and entire, in the Catholic Church. Elsewhere, parts of it are found.

Churches and Ecclesial Communities

This leads to a distinction that sometimes causes offence but is meant precisely.

In Dominus Iesus (2000), the Congregation for the Doctrine of the Faith distinguished between two kinds of Christian communities not in full communion with Rome.

Churches in the proper sense, such as the Orthodox Churches, have preserved apostolic succession and a valid Eucharist. They are “true particular Churches,” united to the Catholic Church by very close bonds, though lacking full communion with the Pope.

Ecclesial communities, such as most Protestant bodies, have not preserved a valid episcopate and the full reality of the Eucharist. The Church therefore does not call them Churches “in the proper sense.” She still recognises that their members are baptised into Christ, that they are in a certain, though imperfect, communion with the Church, and that the Holy Spirit uses their communities as means of salvation (Unitatis Redintegratio 3; CCC 819).

This language is not an insult. It is an attempt to describe accurately the different degrees of communion that exist among Christians.

Why It Matters for Ecumenism

The subsistit in teaching makes Catholic ecumenism possible, and it also shapes it.

Because elements of the Church exist outside her visible boundaries, the Catholic Church can recognise other Christians as brothers and sisters in Christ, pray with them, and work with them. The Council called these elements “forces impelling toward catholic unity”: they naturally tend towards the fullness from which they come.

But because the Church of Christ subsists only in the Catholic Church, Catholic ecumenism is not a search for a new Church that does not yet exist, assembled from the pieces of existing ones. It is a search for the full unity of all Christians in the one Church that Christ founded and that still exists.

Continuity, Not Rupture

The debate over subsistit in is a good example of how the Second Vatican Council should be read. Pope Benedict XVI called this the “hermeneutic of reform in continuity”: interpreting the Council in harmony with the Church’s earlier teaching, not as a break from it.

Read in that light, the phrase says what the Church has always believed, while saying more clearly something she had always known: that Christ’s grace is not confined to the visible boundaries of His Church, even though His Church is found in its fullness in only one place.